JIALINGBO

Multifunctional additive 4-amino-5-bromo nicotinic acid (ABrNA) is used to improve the performance of perovskite solar cells. Due to its multifunctionality, ABrNA can function as a universal additive, applicable to both MA-free and MA-containing perovskites, with bandgaps ranging from 1.53 to 1.73 eV. The versatility of the additive is further confirmed for perovskite modules in both p-i-n and n-i-p architectures.

Abstract

The performance of perovskite solar cells has significantly improved over the years in part due to defect passivation in the bulk and at the interfaces. While many additive molecules have been reported in the literature, they are commonly applicable only to one particular perovskite composition. Here we investigate a multifunctional additive, 4-amino-5-bromo nicotinic acid (ABrNA), for use in both methylammonium (MA)-free perovskites with different Br content (bandgaps ranging from 1.53 to 1.73 eV) as well as MA-containing perovskites. Significant performance improvements are obtained for all compositions, which can be attributed to the presence of multiple functional groups capable of modifying the crystallization of the perovskite as well as passivating defects. Exceptional features of ABrNA make it a promising universal passivator, which leads to a PCE increase from 23.9% to 25.0% for CsFAMA solar cells, and from 22.0% to 23.0% for MA-free solar cells. The ABrNA passivated MA-free devices also exhibit exceptional operational stability, with T₉₀ exceeding 1000 h under ISOS-L-1 testing conditions. In addition, significant performance improvement is observed with ABrNA for modules in both conventional and inverted device architectures, further confirming the universality of ABrNA additive.

A chlorine-substituted aromatic polycyclic compound is introduced into perovskite solar cells to regulate perovskite crystallization, passivate various defects, and enhance hole transport at the HTL/perovskite interface. This approach achieved high efficiencies of 25.04% for 1 cm² cells and 22.81% for 12 cm² modules, with excellent stability (maintaining 80% of initial efficiency after 2500 h of MPP tracking under ISOS-L-1 standards).

Abstract

Film morphology and surface/interface defect density play a critical role in determining the efficiency and stability of perovskite solar cells (PSCs). Here, a chlorine-substituted aromatic polycyclic derivative (BNCl) is reported, which shows strong interaction with both lead iodide and dimethyl sulfoxide, to regulate the crystallization of perovskite, along with effective passivation of grain boundaries and surface. In addition, the extruded BNCl molecule at the hole transport layer (HTL)/perovskite interface can facilitate the hole transport, leading to better charge transfer. As a result, certified power conversion efficiencies (PCEs) of 25.04% and 22.81% are achieved for PSCs and minimodules with aperture areas of 1 cm² and 12 cm² respectively. In addition, the device maintained 80% of its initial efficiency after 2500 h of maximum power point (MPP) tracking under ISOS-L-1 standard.

A multifunctional additive, 1,4-bis(3-mercaptobutyryloxy)butane (BD1), significantly enhances inkjet-printed perovskite quantum dot light-emitting diodes by simultaneously optimizing ink rheology, enabling defect passivation through dithiol and carbonyl interactions, and promoting cross-linking via thiol groups. These synergistic effects lead to the formation of robust and stable quantum dot film networks, resulting in a record-high external quantum efficiency of 21.73%, highlighting BD1’s potential for high-performance quantum dot display applications.

Abstract

Inkjet printing provides a scalable, cost-effective approach for fabricating perovskite quantum dot light-emitting diodes (Pe-QLEDs), particularly suited for high-resolution display applications. However, challenges such as poor ink printability and limited stability of perovskite quantum dots (Pe-QD) inks have impeded its widespread adoption. To overcome these limitations, 1,4-bis(3-mercaptobutyryloxy)butane (BD1), a dithiol-based cross-linkable additive is introduced to enable high-performance inkjet-printed Pe-QLEDs. BD1 serves three critical functions: i) it optimizes the rheological properties of the ink, promoting uniform droplet formation and adaptable inkjet printing process; ii) its thiol groups coordinate with under-coordinated Pb²⁺ sites on the QD surface, mitigating ligand loss during ink formulation and deposition, thus reducing defect density and enhancing optical quality; and iii) it participates in a thiol-ene click reaction with oleic acid ligands, forming robust crosslinked networks that improve film integrity and device stability. By leveraging these synergistic effects, BD1-enabled Pe-QLEDs achieve a record-high external quantum efficiency (EQE) of 21.73%, a peak luminance of 30,637.82 cd m^{− 2}, and an enhanced operational lifetime. This additive engineering strategy also demonstrates versatility across red and blue Pe-QLEDs, highlighting its broad applicability. Collectively, the findings position BD1 as a highly effective multifunctional additive for stabilizing and optimizing Pe-QD inks, paving the way for scalable production of high-resolution, full-color Pe-QLED displays and other printed optoelectronic devices.

By incorporating SbCl3 into phenylethylammonium iodide (PEAI)-based 2D perovskites, n-type doping is achieved and implemented in 3D/2D perovskite heterojunction devices. This strategy yields a 33.10% (certified 32.56%) PCE for the perovskite-silicon tandem solar cells, with improved operational stability.

Benzamidinium chloride (BMCl) is used to homogenize vertical strain in wide-band-gap perovskite films, suppressing ion migration and defect formation. This strategy strengthens lattice stability, enabling 4T perovskite/silicon tandem solar cells with record efficiency (33.4%) and improved outdoor operational stability, demonstrating a scalable approach for durable, high-performance tandem photovoltaics.

Introducing MCC into Me-4PACz-based SAMs enhances interface uniformity and reduces non-radiative recombination, thereby improving carrier transport and device stability. The PCE of the inverted PSCs based on 1.53 and 1.67 eV perovskites is achieved at 26.78% (certified 26.65% for steady state) and 23.78%, respectively, with excellent thermal stability and operational stability. This strategy has been successfully scaled to bifacial modules, offering a versatile approach for high-performance PSCs.

Abstract

Interface engineering remains a critical bottleneck in advancing the performance and operational stability of inverted perovskite solar cells (PSCs). Here, a molecular doping strategy is presented by incorporating methyl 3-chlorosulfonyl-2-thiophenecarboxylate (MCC) into [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) self-assembled monolayers (SAMs). This approach significantly enhances molecular packing, film uniformity, and interfacial passivation. The multifunctional MCC molecule, with its π-conjugated thiophene, sulfonyl chloride, and ester groups, enables dipolar alignment, chemical coordination with Pb²⁺, and improved wettability—collectively promoting superior perovskite crystallization and suppressed non-radiative recombination. Devices based on MCC-doped SAMs achieve outstanding power conversion efficiencies of 26.78% (certified 300s steady-state 26.65%) and 23.78% for PSCs based on 1.53 and 1.67 eV perovskite absorbers, respectively, with remarkable operational stability exceeding 2000 h. Notably, the strategy is successfully extended to large-area, bifacial semi-transparent PSC modules, demonstrating the double-sided efficiencies of 15.51% and 14.64%, respectively, which exhibit strong potential for application in building-integrated photovoltaics (BIPV) in the future. This work establishes a scalable and generalizable strategy for buried interface regulation, offering a compelling pathway toward highly efficient, stable, and manufacturable inverted PSCs.

A fluorine-containing hyperbranched polymer is developed to guide oriented crystallization and construct a cross-linked hydrophobic network, enabling the formation of high-quality perovskite films with enhanced environmental stability. The resulting devices deliver a PCE of 26.05% (0.04 cm²) and 22.43% (16.1 cm²), while maintaining 97% of their initial efficiency after 1500 h of unencapsulated operation at 50–55 °C under continuous illumination.

Abstract

Solution-processed perovskite solar cells have significant potential for large-scale manufacture, but the production of perovskite film with high crystallinity over large areas remains a major challenge. Here, a fluorine-containing hyperbranched polymer is shown for meticulous control of the perovskite film crystallization. Synergistic coordination of functional fluorine groups and perovskite species constrains the complex intermediate phases and facilitates the formation of spatially oriented perovskite films with high crystallinity and phase purity. Simultaneously, the thermal radical polymerization during the annealing process creates a cross-linked hydrophobic network, which enhances resistance to moisture. This results in efficient regular planar perovskite solar cells with a remarkable power conversion efficiency of 26.05% for small devices (active area 0.04 cm²) and 22.43% for large devices (active area 16.1 cm²) under simulated AM 1.5G sunlight (100 mW cm⁻²). Moreover, the unencapsulated devices exhibit excellent operating stability, with 97% of initial efficiency remaining at the maximum power point tracking for 1500 h under continuous illumination (one sunlight intensity) at 50–55 °C.

The ─SO₃ ⁻ and C═O interact with uncoordinated Pb²⁺ ions on the perovskite surface. K⁺ ions occupy interstitial sites within the crystal lattice, thereby suppressing halide phase segregation. Owing to the dual-anchoring effect, a single-junction WBG PSC, achieves a PCE of 22.95% and a V_OC of 1.26 V. Furthermore, a PSTSC exhibits a PCE of 31.20% and a V_OC of 1.950 V.

Abstract

The efficiency and stability of wide bandgap (WBG) perovskite solar cells (PSCs) are constrained by photo-induced halide segregation and severe non-radiative recombination, which significantly impedes the advancement of high-efficiency and stable perovskite/silicon tandem solar cells (PSTSCs). In this work, a potassium 4-sulfonic-1,8-naphthalic anhydride salt (4S-NAPS), featuring dual-anchoring sites, is incorporated into the perovskite precursor. The sulfonic group (─SO₃ ⁻) and carbonyl group (C═O) interact with uncoordinated Pb²⁺ ions on the perovskite surface. In addition, K⁺ ions occupy interstitial sites within the crystal lattice, thereby effectively enhancing the ion migration barrier and suppressing halide phase separation. Owing to the dual-anchoring effect of 4S-NAPS, a single-junction WBG PSC (1.68 eV) delivers a power conversion efficiency (PCE) of 22.95% and an open-circuit voltage (V_OC) of 1.26 V, representing one of the highest efficiencies reported for WBG PSCs. Moreover, the unencapsulated modified devices retain 90% of initial efficiency after 3000 h in a nitrogen atmosphere, demonstrating remarkable operational stability. Notably, the fabricated monolithic PSTSC achieves a PCE of 31.20%, a V_OC of 1.950 V, and exhibits negligible hysteresis. This dual-anchoring strategy provides a promising avenue for fabricating highly efficient and stable WBG PSCs and offers new insights into achieving superior performance in PSTSCs.

A metal–organic salt, potassium perfluorohexylethanesulfonate (PPFES) is introduced to modulate the perovskite/electron transport layer interface, concurrently passivating perovskite surface defects, enhancing charge extraction, and bolstering moisture resistance at the interface. Consequently, PPFES-modified perovskite solar cells deliver a champion power conversion efficiency of 25.32%, featuring an ultrahigh fill factor of 86.39%.

Abstract

Interfacial non-radiative recombination in inverted (p-i-n) perovskite solar cells (PSCs) critically limits both efficiency and stability of the devices. To address this challenge, a metal–organic salt, potassium perfluorohexyl ethyl sulfonate (PPFES), featuring a multidentate sulfonate (SO₃ ⁻) moiety and a hydrophobic perfluoroalkyl tail, is introduced to regulate the perovskite/electron transport layer (ETL) interface. Comprehensive theoretical and experimental analyses reveal that PPFES modulation synergistically passivates the surface defects of perovskite via sulfonate-Pb chelation, shields the perovskite against moisture ingress, and optimizes the energy band alignment at the perovskite/ETL interface. As a consequence, the PPFES-tailored PSCs deliver a champion power conversion efficiency (PCE) as high as 25.32%, with an ultra-high fill factor of 86.39%, reaching 95.6% of the Shockley-Queisser limit at a bandgap of 1.55 eV. Moreover, the devices retain 90% and 88% of their initial PCEs after 1200 h of storage in air with 60% relative humidity and 1300 h of maximum power point tracking under AM 1.5G illumination at 35 °C in ambient, respectively. This work establishes a multi-effect interfacial engineering paradigm that concurrently achieves defect passivation and stability enhancement in PSCs.

In this review, the chemical origins of defects at the top interface of perovskites are systematically examined and summarize the recent progress toward top-interface passivation strategies for IPSCs from molecular-perspective insights.

Abstract

Inverted perovskite solar cells (IPSCs) have emerged as a promising research focus in photovoltaics due to their outstanding optoelectronic properties. However, the further development of IPSCs on efficiency and stability is still limited by the rich defects of perovskites, especially at the top interface of the film. To address the challenge of defects, researchers have demonstrated various studies to suppress the defect effects and enhance the device performance of IPSCs. This review systematically examines the chemical origins of defects at the perovskite top interface and summarizes recent progress in interfacial passivation strategies. Specifically, first various top interface defects and the mechanisms of them influence the perovskite film and device performance are analyzed. Second, this review critically evaluates the efficacy of state-of-the-art passivation strategies, including organic amine halides for 2D/3D heterostructure engineering and tailored molecular structures, Lewis acid and Lewis base passivation, multifunctional group synergistic passivation, and other passivation strategies. The evaluation criteria integrate molecular-level design rationality, interface engineering, and in situ characterization strategies. Finally, this review concludes and establishes fundamental design principles for high-stability passivation materials and critically evaluates their scalability potential, aiming to provide theoretical guidance for the development of highly efficient and stable IPSCs.

Self-assembled naphthalimide-based molecular layers unlock high-efficiency electron-selective contacts in perovskite solar cells. Systematic tuning of substituents and linker lengths reveals key structure–function relationships, achieving up to 20.6% PCE without charge-selective metal oxide layers. This work sets a new benchmark for SAM-based interfaces, advancing scalable, efficient perovskite photovoltaics through precise molecular engineering.

Abstract

Charge-selective contacts critically influence carrier dynamics and overall performance in halide perovskite solar cells (PSCs). Self-assembled monolayers (SAMs) have emerged as a powerful strategy for precise interfacial engineering, enabling tailored energy level alignment and interfacial interactions to enhance charge extraction. Despite their promise, clear structure–function relationships for SAMs—particularly as electron-selective contacts (ESCs)—remain poorly developed. Here, a series of naphthalimide (NI)-based SAMs functionalized with cyano, bromo, or methoxy groups and varying alkyl linker lengths are systematically evaluated as ESCs in n-i-p PSCs. Devices incorporating these SAMs exhibit power conversion efficiencies (PCEs) ranging from 5.8% to 20.6%, depending on molecular structure. The highest PCE is achieved using a SAM with a strongly electron-withdrawing cyano group and a short ethyl linker, attributed to deep LUMO alignment and efficient charge transport at the interface. In contrast, SAMs with longer linkers or higher energy levels yield inferior performance. These results reveal critical design principles for high-performance SAM-based ESCs and establish a new PCE benchmark for PSCs employing standalone SAMs, without auxiliary metal oxide layers. Overall, this work underscores the potential of molecularly engineered SAMs to enable scalable, efficient, and commercially viable perovskite photovoltaics through optimized interfacial control.

Surface passivation treatments are critical for enhancing the power conversion efficiency of perovskite/c-Si tandem solar cells. However, different postsurface treatment methods exhibit variations in passivation efficiency for film defects and conformal deposition on textured surfaces. This work reports the implementation of molecular passivation and heterojunction passivation in high-efficiency tandem devices. Furthermore, it compares the passivation performance differences on textured surfaces among various techniques, including solution processing and vacuum deposition.

As the pursuit for cost reduction of photovoltaic technologies goes on, the interest in high-efficiency Si-tandem solar cells has been strongly increasing, among which perovskite/silicon has demonstrated impressive results and prospects for further enhancements. However, the existence of deleterious defects at the surface of wide-bandgap perovskite films in the top solar cells dramatically impedes the potential industrial applications of perovskite/silicon tandem solar cells. In this review, begin by summarizing the various types of defects and the passivation mechanisms to provide guidance for the passivation protocols. Then, it highlights the reasons for device performance enhancement of the most widely used passivation strategy, chemical bonding passivation, which works by either assembling a thin molecular layer (molecular passivation) or inducing the formation of a low-dimensional perovskite (heterojunction passivation) at the 3D perovskite surface. Next, an overview of the passivating treatments for perovskite films deposited on crystalline silicon and their fabrication requirements is presented. Finally, the challenges and knowledge gaps for breaking bottlenecks in the commercialization of perovskite/silicon tandem solar cells are proposed.

The residual PbI₂ was made to form stable metal-organic complexes at the grain boundaries by 2-iodoimidazole (2-IM). The inverted 1.66 eV PSCs achieved a PCE of 24.12%. This strategy has good universality and achieved an efficient 1.53 eV PSCs with a PCE of 26.84%. Inverted wide bandgap PSCs maintained 94% of their initial efficiency after continuous operation for 1000 hours at the maximum power point.

Abstract

The grain boundaries (GBs) instability induced by photodecomposition of residual PbI₂ is long-standing challenge for further simultaneous improvement of stability and power conversion efficiency (PCE) of perovskite solar cells (PSCs). Herein, a novel GB stabilization strategy through managing unstable residual PbI₂ within perovskite films is reported, which is realized by incorporating 2-iodoimidazole (2-IM) into perovskite precursor solution. The 2-IM can in situ convert unstable residual PbI₂ at GBs into robust metallo-organic complex 2-IMPbI₂ exhibiting an orderly hexagonal layered crystal structure. 2-IMPbI₂ is uncovered to have much better defect passivation effect and stability than PbI₂. The formed 2-IMPbI₂ facilitates perovskite crystallization, passivates GB defect, suppresses ion migration, mitigates phase segregation, and promotes carrier transport, contributing to simultaneously enhanced PCE and stability. Owing to the ingenious GB modulation strategy, the inverted 1.66 eV PSCs achieve a PCE of 24.12%, which is among the highest PCEs ever reported for 1.66 eV PSCs. This strategy demonstrates good universality by accomplishing efficient 1.53 eV PSCs with a PCE of 26.84%. Moreover, the inverted wide-bandgap PSCs with 2-IMPbI₂ maintain 94% and 90% of their initial efficiencies after 1000 h of continuous maximum power point operation and after 500 h of thermal stress at 85 °C, respectively.

A mixed-halide perovskite film with initially homogeneous phase distribution is obtained by using 3-amino-5-fluorobenzamide additive, which selectively suppresses bromide precipitation during crystallization to mitigate halide phase segregation while demonstrating weak size dependence. The resulting 1.004-cm² perovskite/organic tandem solar cells achieved a remarkable 25.21% power conversion efficiency, coupled with impressive operational stability maintaining ≈90% initial performance over 1500 h.

Abstract

Mixed halide wide-bandgap (WBG) perovskites, used in high-performance perovskite/organic tandem solar cells (TSCs), are prone to phase segregation under light irradiation. Particularly, the initial inhomogeneous halide phase distribution in WBG perovskites can accelerate the phase segregation under operational stressors, thus hindering scaling of TSCs that require high phase homogeneity. Here, a selective delayed crystallization strategy is proposed in which a functional agent (3-amino-5-fluorobenzamide; AFBA) is used to regulate the initial halide phase distribution. The -NH₂ of AFBA, with a low electron-cloud density, shows a higher binding affinity with bromide than with iodide, thus selectively delaying the rapid crystallization of bromide; this phenomenon induces a homogeneous halide distribution across the film. The initial homogeneous film is phase-stable under operational stressors. As a result, the square-centimeter WBG perovskite front cell achieves a high efficiency of 18.61%. When stacked with organic subcells, the square-centimeter perovskite/organic TSC exhibits a remarkable efficiency of 25.21%, showing a weak-dependence of efficiency on size from 0.062 to 2.000 cm², as well as a prolonged operational lifetime with a T ₉₀ of 1500 h. Perovskite/organic TSCs are also connected in series with electrochromic devices to dynamically monitor the TSC performance via the color variation, providing insights for their future applications.

A systematic interfacial passivation strategy employing alkylammonium iodide salts with tunable carbon chain lengths (C1–C12) dramatically enhances efficiency and stability in perovskite solar cells. Optimal passivation with dodecylammonium iodide achieves a power conversion efficiency of 24.6%, highlighting improved open-circuit voltage, fill factor, and remarkable operational stability under ambient and thermal conditions.

Power conversion efficiency (PCE) improvements in perovskite solar cells (PSCs) are increasingly constrained by nonradiative recombination at interfacial defects. In this study, we demonstrate a systematic interface engineering strategy using alkylammonium iodide salts with varying chain lengths from methylammonium (C1) to dodecylammonium (C12) to modulate the interface between the mixed-cation perovskite absorber (FAPbI₃)_0.97(MAPbBr₃)_0.03 and the hole-transport layer. Surface treatment with these salts significantly reduces interfacial recombination, as evidenced by enhanced photoluminescence and a strong chain-length-dependent increase in open-circuit voltage (V _OC) and fill factor (FF). Our champion device, passivated with dodecylammonium iodide, achieves a PCE of 24.6% with V _OC = 1.166 V and FF = 81.5%, marking a > 12% relative increase over the untreated control. Structural, optical, and electrical (J–V, SCAPS modeling) analyses collectively reveal that longer-chain cations form ultrathin 2D interfacial layers that suppress defect-mediated recombination without impeding charge transport. Additionally, these passivation layers impart enhanced stability under continuous illumination, ambient air exposure, and elevated temperature, with DDAI-treated devices maintaining over 88% of their initial performance after thermal aging at 65°C for 500 h. This work establishes alkylammonium chain length as a powerful tuning parameter for optimizing PSC interfaces and advancing high-efficiency, stable perovskite photovoltaics.

We developed a synergistic self-assembled monolayer (syn-SAM) strategy by blending a non-planar molecule ABT with the commonly used Me-4PACz SAM. 1.56 eV single-junction PSCs achieved a maximum PCE of 25.75% (certified 25.45%). This approach is also beneficial for monolithic perovskite/silicon tandem solar cells based on fully textured HJT silicon bottom cells, achieving record PCEs of 31.56% (area: 1.07 cm²) and 26.57% (area: 20.06 cm²).

Abstract

Carbazole-based self-assembled monolayers (SAMs) have been commonly used as a single-component hole transport layer (HTL) in inverted perovskite solar cells (PSCs), but suffer from facile π-π stacking and self-aggregations in solution and consequently poor anchoring ability with the atop perovskite layer. Herein, we developed a synergistic SAM (syn-SAM) strategy through blending a non-planar molecule 3,3-(4-amino-4H-1,2,4-triazole-3,5-diyl)-dibenzo acid (ABT) bearing multiple anchoring sites with the commonly used Me-4PACz SAM. The coexistence of these two components leverages π-π interactions and hydrogen bonding to mitigate aggregation effects, affording dense and uniform SAM, thereby enhancing anchoring at the perovskite buried interface and alleviating interfacial charge recombination. ABT incorporation further helps to mitigating tensile strain in perovskite film. Additionally, this strategy offers advantages of multi-device compatibility. The single-junction champion inverted PSC devices based on syn-SAM deliver power conversion efficiencies (PCEs) of 25.75% (certified 25.45%) and 22.76% (area: 0.105 cm²) for 1.56  and 1.68 eV bandgap perovskites, respectively. Moreover, this approach is beneficial for the monolithic perovskite/silicon tandem solar cells based on fully textured surfaces of heterojunction (HJT) silicon bottom cells, affording PCEs of 31.56% (area: 1.07 cm²) and 26.57% (area: 20.06 cm²). All devices exhibit excellent long-term storage and thermal stability even under non-encapsulated conditions.

Publication date: October 2025

Source: Nano Energy, Volume 143

Author(s): Yanjie Wu, Anudari Dolgormaa, Yichi Zhang, Liu Yang, Bing Yao, Hongmei Zhan, Yanxiang Cheng, Lixiang Wang, Chuanjiang Qin

A perfluorination strategy using perfluorotriethylamine (PFTEA) enables simultaneous surface defect passivation and lead immobilization in inverted perovskite solar cells. This approach yields a certified efficiency of 26.65% and excellent long-term operational stability, offering a promising route toward high-performance and environmentally sustainable perovskite photovoltaics.

Abstract

The intrinsic instability and nonradiative recombination induced by surface defects hinder the further development of p-i-n inverted perovskite solar cells (PSCs). Simultaneously, the commercial application of inverted PSCs is limited by environmental unfriendliness resulting from lead leakage. Herein, a universal perfluorination strategy is reported to immobilize lead and passivate surface defects of perovskite films in inverted PSCs. It is demonstrated that perfluorinated perfluorotriethylamine (PFTEA) can form PFTEA·PbI₂ complex with PbI₂ via a strong coordination bond, which is favorable for suppressing lead leakage and promoting defect passivation. Due to much reduced surface nonradiative recombination, the PFTEA-modulated inverted PSCs deliver a fascinating certified stabilized power conversion efficiency (PCE) of 26.65%, a record efficiency value reported for PSCs using the vacuum flash evaporation technique. Moreover, the PFTEA-modulated devices maintain 92% of their initial PCE after 1000 h of continuous maximum power point tracking. This work provides a simple and effective avenue to advance the sustainable development of inverted photovoltaic technology through a perfluorination strategy.

A novel π-conjugated SAM molecule, namely PAInCz, which combines the indeno[1,2-b]carbazole terminal with a flexible butyl linker, has proven to be particularly effective. It can promote strong ITO anchoring as well as favorable perovskite interfacial contact. The optimized inverted PSCs based on PAInCz have achieved a PCE of 25.51% and exhibit excellent operational stability.

Abstract

Terminal π-extension is crucial for fabricating highly ordered self-assembled monolayers (SAMs) that facilitate efficient hole transport in perovskite solar cells (PSCs). However, π-expanded conjugation may compromise SAM film quality and ultimately degrading interfacial properties in p–i–n PSCs. To resolve this trade-off, SAMs incorporating an indenocarbazole (InCz) terminal group are designed, which simultaneously addresses both molecular ordering and film formation challenges. The InCz-terminated PAInCz demonstrates optimal balance through: 1) strengthened π-interactions enabling dense, ordered molecular stacking, and 2) dimethyl steric hindrance enhancing film quality. Notably, while PAInCz exhibits superior performance-including enhanced perovskite interfacial contact, robust ITO substrate anchoring, and favorable energy alignment, its π-extended counterpart Ph-PAInCz (featuring both extended terminal and linker groups) showed diminished device performance. This contrast highlights the importance of controlled π-conjugation in SAM design. The optimized PAInCz-based inverted PSCs achieved a champion power conversion efficiency of 25.51% with exceptional operational stability, maintaining > 85% of initial PCE after 500 h of continuous light soaking (AM1.5G) and thermal stress testing (65 °C). These findings provide fundamental insights into how the π-extension terminal and linker of SAMs influence the performance of perovskite solar cells.

Amphiphilic block copolymer micelles serve as templates to precisely control the formation, size, and stability of CsPbBr₃ perovskite nanocrystals by modulating the reaction kinetics of precursors within the micelles.

Abstract

Metal halide perovskite nanocrystals (PNCs) have attracted significant research interest owing to their exceptional photovoltaic properties and their potential applications in photovoltaics and light-emitting devices. However, stabilizing individual PNCs while maintaining their intrinsic properties remains a great challenge. In this study, a facile yet robust approach is introduced by utilizing polystyrene-block-poly(4-vinyl pyridine) (PS-b-P4VP) block copolymer micelles as templates to precisely control the formation, size, and stability of CsPbBr₃ PNCs. Interestingly, the reaction kinetics of PNC precursors in the micelles can be modulated by stacking of polymer chains via crosslinking of P4VP cores or collapsing of micelle templates, enabling facile control over the geometry of PNCs inside the micelles. By tuning the molecular weight of P4VP, precise size control of the CsPbBr₃ PNCs can be achieved. Most importantly, the hydrophobic PS shell enhances the stability of PNCs against moisture and polar solvents (e.g., methanol, ethanol, dichloromethane, etc.) without interference in ion exchange processes. The approach enables the in situ growth of monodisperse CsPbBr₃ PNCs, offering a straightforward and scalable method for fabricating highly stable, size-controlled PNCs suitable for optoelectronic applications.

A novel bidentate-anchored superwetting aromatic self-assembled monolayer is employed as a hole-selective layer (HSL) in inverted wide-bandgap PSCs. The reversely substituted carbazole approach is crucial in promoting the formation of a robust HSL, improving hole extraction efficiency. The optimized wide-bandgap PSCs attain a power conversion efficiency (PCE) of 22.83%, and the fabricated P/S-TSCs achieve an impressive efficiency of 32.19% (certified 31.54%) while maintaining excellent photostability.

Abstract

The inhomogeneity of hole-selective self-assembled molecular layers (SAMLs) often arises from the insufficient bonding between anchors and metal oxide, particularly on textured silicon surfaces when fabricating monolithic perovskite/silicon tandem solar cells (P/S-TSCs) and the hydrophobic carbazole complicates the fabrication of high-quality perovskite films. To address this, we developed a novel bidentate-anchored superwetting aromatic SAM based on an upside-down carbazole core as a hole-selective layer (HSL), denoted as ((9H-carbazole-3,6-diyl)bis(4,1-phenylene))bis(phosphonic acid) (2PhPA-CzH). The bisphosphonate-anchored exhibited enhanced adsorption capabilities and efficient hole extraction/transport, and the reversely substituted carbazole ring contributed a friendly super wetting underlayer that enabled high-quality perovskite films with minimized energetic mismatches, which 2PhPA-CzH played a pivotal role in dual interfacial energy regulation. Through these advancements, the optimized wide-bandgap (1.68 eV) PSCs demonstrated an improved PCE of 22.83% and excellent stability with T₉₀ exceeding 1000 h under damp-heat conditions (ISOS-D-3, 85% RH, 85 °C), representing one of the best performances for SAMs as HSL-based PSCs. Notably, 2PhPA-CzH-functionalized recombination layers extended to submicron-pyramid texture SHJ to fabricate P/S-TSCs, achieving an impressive efficiency of 32.19% at an active area of 1 cm² (certified 31.54%) while maintaining excellent photostability. This work offers guidance for designing multidentate-anchored SAMs to realize record PCE and excellent stability in P/S-TSCs.

Nature Energy, Published online: 04 June 2025; doi:10.1038/s41560-025-01781-1

Seo et al. present an approach to regulate the formation and optoelectronic quality of the SnO2 electrodes, improving electroluminescence and efficiency in perovskite solar cells.

3-(N, N-Dimethyloctylammonio) propananesulfonate inner salt (DOPS) as an ionic surfactant additive is utilized in large-area wide-bandgap (WBG) perovskite film preparation. The well-designed interaction between DOPS and WBG compositions effectively regulates the crystallization process and passivates the uncoordinated Pb²⁺. These improvements enable champion efficiencies of 16.38% and 23.41% for WBG and all-perovskite tandem solar modules.

Abstract

The development of scalable all-perovskite tandem solar cells offers a promising pathway for perovskite photovoltaic commercialization. However, the certified efficiency of all-perovskite tandem mini-modules still lags much behind their small-area (≈0.1 cm²) counterparts. This performance gap primarily stems from inhomogeneities and inferior crystallinity in wide-bandgap (WBG) perovskite solar cells (PSCs) when scaling up. In this work, we introduced 3-(N, N-Dimethyloctylammonio) propananesulfonate inner salt (DOPS) as an ionic surfactant additive to suppress pinhole formation and enhance the uniformity of large-area perovskite films. The well-designed interaction between DOPS and WBG compositions effectively regulates the crystallization process and passivates the uncoordinated Pb²⁺, resulting in a uniform and high-quality WBG perovskite film with suppressed non-radiative recombination. These improvements enable champion efficiencies of 19.57% and 16.38% for WBG PSCs with aperture areas of 1.0 and 20.07 cm², respectively. Furthermore, when integrating this optimized WBG device into all-perovskite tandem solar cells, it yields impressive PCEs of 27.82% (1.0 cm²) and 23.41% (20.07 cm²). Overall, these findings present an effective strategy for enhancing large-area uniformity via the surfactant synergistic effect of crystallization regulation and defect passivation.

The effects of alkylammonium acetates with varying dipole moments on the interface between the perovskite and the hole transport layer are compared. Both theoretical and experimental analyses indicate that hexylammonium acetate provides the optimal energy level arrangement and effective defect passivation. As a result, perovskite solar cells achieve an efficiency of 25.06%, along with enhanced mechanical stability in flexible devices.

Abstract

Interface modification with the ability to passivate defects and regulate interface energy level is an important method to maximize the photovoltaic performance of perovskite solar cells (PSCs). Herein, through modifying the interface between perovskite and hole transport layer via different alkylammonium acetate ionic liquid molecules with varied dipole moments, efficient and stable PSCs are achieved. Especially, hexylammonium acetate (HAAc) with high dipole moment can reduce the energy difference between perovskite and hole transport layer to facilitate hole extraction and reduce energy loss. In addition, HAAc has a strong chemical binding ability to both acceptor and donor defects on perovskite surfaces through synergistic passivation of HA⁺ cation and Ac⁻ anion, thereby reducing defect-assisted recombination. The combined effects of energy level modulation and defect suppression lead to an overall enhancement in device performance. The best HAAc-passivated device reaches an efficiency of up to 25.06% and maintains > 97.30% initial efficiency for 1000 h in air with 30 ± 10% humidity. In addition, the flexible perovskite solar cells exhibit excellent mechanical stability, with efficiency remaining above 71% of the initial value after 10 000 bending cycles at a small bending radius of 5 mm.

A multifunctional interfacial molecular bridging strategy is proposed, for the first time, to address the upper interfacial issues of inverted PSCs by stabilizing the upper interface between perovskites and PCBM electron transport layer (ETL), passivating interfacial defects, and improving the energy band alignment.

Abstract

Interface engineering in inverted perovskite solar cells (PSCs) faces critical challenges arising from nonideal interfacial contact, defect accumulation, impeded carrier transport, and energy-level misalignment between the perovskite and electron transport layer, for example, phenyl-C61-butyric acid methyl ester (PCBM). These interfacial deficiencies collectively induce nonradiative recombination and degrade device stability. Herein, a multifunctional interfacial molecular bridging strategy using (benzhydrylthio)acetic acid (DSA) addresses the upper interfacial issues of inverted PSCs, achieving three synergistic roles. 1) Interfacial stabilization. A stable molecular-bridging layer is constructed with DSA at the perovskite/PCBM interface through carboxylate–Pb²⁺ coordination bonds, along with π–π stacking interactions between DSA and PCBM. 2) Defect passivation. Multiple active sites in DSA molecules, such as thioether and carboxylic acid groups, can synchronously achieve chemical passivation with undercoordinated Pb²⁺ sites. 3) Energy band alignment: DSA induces n-type band bending through electron donation by the thioether, reducing the work function and enhancing the electron-extraction kinetics. As a result, DSA-treated devices achieve a champion power conversion efficiency of 26.08% along with an open-circuit voltage loss of only 53 mV. Finally, the DSA-treated devices demonstrate remarkable operational stability, retaining 96% of the initial efficiency after being tracked at the maximum power point for 2000 h.

A doping strategy of incorporating Bis(trifluoroacetoxy)iodo)benzene (BTFIB) additive in 1.67 eV WBG perovskite precursor has been proposed to passivate uncoordinated lead ions and iodide vacancies and retard the crystallization of perovskite. Finally, BTFIB-based perovskite solar cells yielded a champion efficiency of 23.05% (certified 22.21%) and enabled a four-terminal perovskite/Si tandem cell with a PCE of 31.20% and excellent long-term stability.

Abstract

Wide-bandgap (WBG) perovskite solar cells (PSCs, E_g > 1.6 eV), serving as the top cell in perovskite/silicon tandem solar cells (PSTSCs), play an indispensable role in absorbing high energy photons and increasing overall efficiency. However, WBG PSCs often suffer from severe light-induced phase segregation and significant non-radiative recombination losses due to uncontrolled rapid crystallization. Here, polyfluoride molecular additives are designed and incorporated via (diacetoxyiodo)benzene into WBG perovskite, to regulate crystallization process of perovskite films and thereby reduce defects. (Bis(trifluoroacetoxy)iodo)benzene (BTFIB) can passivate uncoordinated lead ions and iodide vacancies, thereby inhibiting phase separation caused by iodide migration and reducing non-radiative recombination loss during charge transport. Moreover, the introduction of BTFIB can effectively moderate the film formation process and confer excellent hydrophobic properties to the films. Consequently, BTFIB-based 1.67 eV-WBG perovskite devices yield a champion efficiency of 23.05% (certified efficiency of 22.21%), enabling a 31.20% efficiency in four-terminal PSTSCs, along with excellent open-circuit voltage of 1.246 V and fill factor of 85.34%. After 2500 h of aging in a glovebox, the device retained 80% of its initial efficiency.

Elemental iodine (I₂) is used to create an iodine-rich environment for inhibiting the formation of iodine vacancy defects. This strategy also modifies the perovskite's surface energy, regulating its crystallization kinetics and resulting in a more well-crystallized perovskite with a preferred (001)-orientation. Consequently, PeLEDs with efficiencies of 32.5% for deep-red (678 nm) and 29.5% for pure-red (649 nm) have been achieved.

Abstract

Perovskite light-emitting diodes (PeLEDs) face a tough challenge that halogen vacancy defects limit device performance, while the introduction of additional agents to passivate defects may potentially compromise the stability of the structure and increase the complexity of the system. Here, elemental iodine (I₂) is employed as an additive, utilizing its ability to create an iodine-rich condition and to transform into I⁻ ions for passivating iodine vacancy defects, while its volatile nature ensures no residue and avoids the introduction of extraneous elements. This approach also alters the perovskite's surface energy and subsequently regulates its crystallization kinetics, which results in a more well-crystallized perovskite with vertically-aligned organic spacer layers, in turn promoting the transport of charge carriers. On the basis of this strategy, PeLEDs with efficiencies of 32.5% and 29.5% for deep-red (678 nm) and pure-red (649 nm) have been achieved, respectively.

The combination of two self-assembled monolayers (SAMs), aka co-SAM, provides an effective way to further improve the performance of perovskite solar cells (PSCs). Herein, the sequential deposition process of co-SAM is optimized in detail. It is discovered that the wettability of co-SAM is mainly determined by the first step, while the energy level can be modulate by the second step. Based on the precisely optimized co-SAM, blade-coated PSC achieves a high efficiency of 25.01% and excellent stability.

Abstract

Self-assembled monolayers (SAMs) have achieved remarkable success in the realm of inverted perovskite solar cells (PSCs). The integration of two distinct SAMs, referred to as co-SAM, significantly broadens the diversity within the SAM family and propels the enhancement of PSC performance. In this study, a co-SAM consisting of [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl] phosphonic acid (MeO-4PACz) and  [2-(3,6-dimethyl-9H-carbazol-9-yl) ethyl] phosphonic acid (Me-2PACz) is sequentially deposited to achieve a precisely controlled nanostructure. It is unveiled that the initial deposition step governs the surface wettability, whereas the subsequent step dictates the energy level alignment. Leveraging this meticulously regulated co-SAM, the blade-coated PSC attains an impressive efficiency of 25.01%, retains 95.4% of its efficiency after 2500 h under illumination, and maintains 86.7% of its efficiency after ≈2000 h at 85 °C. This research delineates a novel pathway to facilitate the large-scale manufacturing of PSCs.

The quasi-2D perovskite intermediate phase induced by propylphenylammonium chloride (PPACl) promotes directional crystallization toward 3D perovskites. This process improves film quality and increases open-circuit voltage, leading to enhanced device performance. This study achieves an efficiency of 21.42%, representing one of the highest reported values for Cs-rich wide-bandgap perovskite solar cells.

Abstract

Cesium lead triiodide (CsPbI₃) perovskitesare promising candidates for top cells in tandem solar cells owing to their superior thermal and photostability. However, their practical application is hindered by poor phase stability, as CsPbI₃ readily converts from the perovskite phase to the non-perovskite phase. To improve both phase stability and efficiency without significantly altering the bandgap, some fraction of formamidinium (FA⁺) is introduced into CsPbI₃. This study demonstrates that a quasi-2D perovskite intermediate effectively modulates the crystallization process and improves the film quality of Cs-rich, pure-iodide wide-bandgap perovskites, leading to a significant enhancement in open-circuit voltage (V_OC). Propylphenylammonium chloride (PPACl) facilitates the formation of a quasi-2D PPA₂(Cs_xFA_1-x)_n−1Pb_nI_3n+1 phase, which acts as a scaffold to promote the oriented crystallization of 3D perovskites. This quasi-2D intermediate can mitigate structural distortion in the perovskite lattice by alleviating lattice mismatch, typically associated with the dimethylammonium lead triiodide (DMAPbI₃) to final α-phase transition. Thus, the approach enhances crystallinity and morphology, reducing defect density and V_OC loss in the 3D perovskite. Consequently, the optimized Cs_0.7FA_0.3PbI₃ perovskite solar cells (PSCs) achieve a power conversion efficiency of 21.42%, marking one of the highest efficiencies reported for Cs-rich wide-bandgap PSCs under standard AM 1.5 G illumination.

In this report, the internal strain affecting the stability of FAPbI₃ perovskite is addressed through the design of additives in the precursor solution. Instead of conventional methylammonium chloride, a triple-additive approach is employed, leading to improved phase stability and reduced strain gradient. The strategy results in enhanced durability and efficiency, with power conversion efficiency retention of 95% after 8000 h under the ISOS-D-1 condition and a maximum PCE of 24.50%.

Abstract

The stability of the FAPbI₃ perovskite phase is significantly affected by internal strain. In this report, additives in the perovskite precursor solution are designed to prevent local lattice mismatch of the resulting perovskite layer. Instead of using a conventional methylammonium chloride (Control), triple additives (Target) are introduced by considering ion association and formation energy. The out-of-plane orientation for the (100) plane is less pronounced by the triple additives compared to the Control film with a highly enhanced preferred orientation, which reduces the strain gradient and the Pb─I bond distance. Moreover, the anisotropic atomic-level lattice strain along (111) plane, associated with the α-to-δ phase transition, is more uniformly distributed by the triple additives. The triple-additive strategy demonstrates exceptional phase stability under relative humidity as high as 90% and the International Summit on Organic Photovoltaic Stability (ISOS)-L-2 protocol. The device lifetime measured under the ISOS-D-1 condition shows that the Target perovskite solar cell (PSC) maintains 95% of its initial power conversion efficiency (PCE) for over 8000 h, and the best PCE of 24.50% is achieved.