JIALINGBO

A novel strategy to neutralize charged point defects in organic‐inorganic hybrid perovskite materials is proposed for highly efficient and stable perovskite solar cells by using a zwitterionic L‐alanine additive, which can be passivated simultaneously with both positively and negatively charged defects because it contains both anion and cation functional groups in one molecule.

Abstract

Ionic defects (e.g., organic cations and halide anions), preferably residing along grain boundaries (GBs) and on perovskite film surfaces, are known to be a major source of the notorious environmental instability of perovskite solar cells (PeSCs). Although passivating ionic defects is desirable, previous approaches using Lewis base or acid molecules as additives suppress only the negatively or positively charged defects, thus leaving oppositely charged defects. In this work, both the cationic and anionic defects inside methyl ammonium lead tri‐iodide (MAPbI₃) are simultaneously passivated by introducing a zwitterionic form of the amino acid, L‐alanine, into the precursor solution as an additive. L‐alanine has both positive (NH₃ ⁺) and negative (COO⁻) functional groups at a specific solvent pH, thereby passivating both the cation and anion defects in MAPbI₃. The addition of L‐alanine increases the grain size of the perovskite crystals and lengthens the charge carrier lifetime (τ > 1 µs), leading to improved power conversion efficiencies (PCEs) of 20.3% (from 18.3% without an additive) for small‐area (4.64 mm²) devices and 15.6% (from 13.5%) for large‐area submodules (9.06 cm²). More importantly, the authors’ approach also significantly enhances the shelf storage and photoirradiation stabilities of PeSCs.

Three new dithieno[2,3‐d;2ʹ,3ʹ‐dʹ]benzo[1,2‐b;4,5‐bʹ]dithiophene based small‐molecule donors with different branching points for alkyl side chains are designed and synthesized for all small molecular organic solar cells. Modifying the branching points tunes the properties in the aggregation state, and an optimal nanofiber‐based hierarchical morphology for efficient charge separation and transport is successfully demonstrated.

Abstract

The optimization of bulk heterojunction morphology is one of the most challenging topics in all‐small‐molecule organic solar cells. Herein, three small molecular donors based on dithieno[2,3‐d;2′,3′‐d′]benzo[1,2‐b;4,5‐b′]dithiophene (DTBDT) unit by systematically moving the branching point of the alkyl chain have been designed, synthesized, and applied in organic solar cells. Modifying the branching points enables the properties of the aggregation state to be tuned, and an efficient nanofiber‐based hierarchical morphology is successfully demonstrated by combining with different nonfullerene acceptors. The molecules with far branching points can form nanofibers in active layers, and theses nanofibers help the charge separation and charge transport in a large donor‐rich or acceptor‐rich domain of approximately 100 nm. Using nonfullerrene Y6 as an acceptor, the highest power conversion efficiency of 14.78% is obtained, which is one of the highest efficiencies in all‐small‐molecule organic solar cells. The strategy of modification of alkyl side chain branching points can be a practical way to actualize crystallinity control and active layer morphology for improving the performance of all‐small‐molecule organic solar cells.

The T2‐CNORH organic passivation layer (OPL) is used to obtain low energy loss organic photovoltaics. The T2‐CNORH‐deposited PM6:Y6 device exhibits a power conversion efficiency (PCE) of 15.5% with low non‐radiative energy loss (0.203 eV). Furthermore, the OPL improves various photoactive layer systems with a best PCE of 16.4% for the PM6:Y7 system.

Abstract

Despite the tremendous development of various high‐performing photoactive layers in organic photovoltaic (OPVs) cells, improving their performance remains the most important challenge in the field. Here, an effective and compatible strategy (i.e., the concept of vacuum deposition of an organic passivation layer (OPL) on the photoactive layer) is presented to enhance the efficiency of the state‐of‐the‐art photoactive systems, where easy‐deposition processable T2‐ORH and T2‐CNORH OPLs are used. After the deposition process, T2‐ORH forms 2D‐like edge‐on crystalline structure, and the 3D‐like face‐on crystalline growth is induced in T2‐CNORH. Resulting from its relatively higher crystalline features and increased wettability with the cathode interfacial material, the performance of T2‐CNORH‐deposited OPVs with both small and the scaled‐up areas surpass devices without OPL and with T2‐ORH. Experimental studies are conducted linking conductivity, electroluminescence quantum efficiency, carrier transport, and recombination dynamics to find the reasons for the performance difference. Furthermore, by applying the T2‐CNORH to other photoactive platforms, the efficiencies are enhanced by 4.4–9.0% relative to those of the corresponding control devices; an optimal 16.4% efficiency is achieved, which validates its great applicability for photoactive layers that will be developed in the near future.

The impact of SnF₂ on FA_{0 . 83}Cs_{0 . 17}Sn _x Pb_{1− x} I₃ perovskite thin films is examined for additive amounts varying between 0.1% and 20%. Structural distortion from lattice strain is reduced by SnF₂ addition. Lower background hole doping, longer photoluminescence lifetimes, and higher charge‐carrier mobilities are observed with as little as 1% SnF₂ added. Larger quantities of the additive introduce defects alongside these beneficial effects.

Abstract

Mixed tin‐lead halide perovskites are promising low‐bandgap absorbers for all‐perovskite tandem solar cells that offer higher efficiencies than single‐junction devices. A significant barrier to higher performance and stability is the ready oxidation of tin, commonly mitigated by various additives whose impact is still poorly understood for mixed tin‐lead perovskites. Here, the effects of the commonly used SnF₂ additive are revealed for FA_{0 . 83}Cs_{0 . 17}Sn _x Pb_{1− x} I₃ perovskites across the full compositional lead‐tin range and SnF₂ percentages of 0.1–20% of precursor tin content. SnF₂ addition causes a significant reduction in the background hole density associated with tin vacancies, yielding longer photoluminescence lifetimes, decreased energetic disorder, reduced Burstein–Moss shifts, and higher charge‐carrier mobilities. Such effects are optimized for SnF₂ addition of 1%, while for 5% SnF₂ and above, additional nonradiative recombination pathways begin to appear. It is further found that the addition of SnF₂ reduces a tetragonal distortion in the perovskite structure deriving from the presence of tin vacancies that cause strain, particularly for high tin content. The optical phonon response associated with inorganic lattice vibrations is further explored, exhibiting a shift to higher frequency and significant broadening with increasing tin fraction, in accordance with lower effective atomic metal masses and shorter phonon lifetimes.

In the structure of perovskite solar cells, N‐type semiconductor AgBiS₂ and dimethyl sulfoxide solvent mixed polyethylene glycol are used for perovskite film treatment. Finally, the perovskite solar cells with dual‐interfacial modification exhibite a remarkable improvement of power conversion efficiency from 18.58% to 21.19%, as well as show the excellent long‐term and moisture stability.

Although the research on perovskite solar cells (PSCs) has achieved rapid progress, its efficiency and stability still need to be further improved to meet the industrial requirements. The defects located inside the cells, on the surfaces, interfaces, or grain boundaries, will primarily affect carrier transportation through the formation of nonradiative recombination centers and hinder the further enhancement of the power conversion efficiency (PCE). Herein, a straightforward and simple defect passivation method is developed to increase the PCE and stability of PSCs. In the device, the N‐type semiconductor AgBiS₂ is introduced by thermal evaporation as a modified layer between the perovskite films and electron transport layer, which can improve the charge transport characteristic and bandgap optimization of PSCs. Simultaneously, dimethyl sulfoxide (DMSO) solvent mixed polyethylene glycol (PEG) is used for solvent annealing treatment, which can further improve the quality of perovskite film and reduce the trap density by increasing grain size and enhancing the crystallinity. As a result, the PSCs with dual‐interfacial modification exhibit a remarkable improvement in PCE from 18.58% to 21.19% with exceptional long‐term and moisture stability. This work provides an innovative insight for fabricating the stable and efficient PSCs toward the industrialization.

Herein, a one‐step solution‐processing of [MA_0.9Cs_0.1Pb(I_0.6Br_0.4)₃] wide‐bandgap perovskite using phenylhydrazine iodide with amino groups to successfully passivate the trap density within grain boundaries and increase the perovskite grain size is demonstrated. The reinforced morphology and grain boundaries treatment considerably enhance the power conversion efficiency from 12.16% for pristine to 14.63% for the treated devices.

Due to the attraction of fabricating highly efficient tandem solar cells, wide‐bandgap perovskite solar cells (PSCs) have attracted substantial interest in recent years. However, polycrystalline perovskite thin‐films show the existence of trap states at grain boundaries which diminish the optoelectronic properties of the perovskite and thus remains a challenge. Here, a one‐step solution‐processing of [ MA0.9Cs0.1Pb(I0.6Br0.4)3] wide‐bandgap perovskite using phenylhydrazine iodide with amino groups is demonstrated to successfully passivate the trap density within grain boundaries and increase the perovskite grain size. The reinforced morphology and grain boundaries treatment considerably enhanced the power conversion efficiency (PCE) from 12.16% for pristine to 14.63% for the treated devices. This strategy can be easily adopted to other perovskites and help realize highly efficient perovskite solar cells.

An interfacial layer of triphenylamine–polystyrene blend is used between the perovskite layer and charge‐transporting layer to concurrently suppress energy loss and improve device stability. The energy loss is reduced from 0.49 to 0.35 eV, along with a large open‐circuit voltage of 1.18 V and a high power conversion efficiency of 22.1% in air‐stable perovskite solar cells.

Energy loss induced by nonradiative recombinations plays a critical role in determining power conversion efficiencies in perovskite solar cells, whereas device stability impacts their long‐time reliability in the ambient environment. It is an important challenge to suppress energy loss and improve device stability simultaneously. Herein, an interfacial layer of triphenylamine (TPA):polystyrene (PS) blend coated on the hybrid perovskite layer to concurrently suppress energy loss and improve device stability is reported. The energy loss is suppressed from 0.49 to 0.35 eV by passivating surface defects in hybrid perovskites via Lewis acid–base interactions with the combination of electron‐donating aromatic nucleus in PS and tertiary amine in TPA, leading to perovskite solar cells with a high open‐circuit voltage of 1.18 V, a fill factor of about 80%, and a power conversion efficiency of 22.1%. Meanwhile, the device stability in the ambient environment is improved significantly by the TPA:PS blend due to its superior hydrophobicity which is suggested by its high contact angle of 91.1° as compared to 64.0° for the pristine perovskite film. Herein, an efficient interfacial engineering approach with the TPA:PS blend to suppress energy loss and improve device stability simultaneously towards realistic applications is demonstrated.

Half‐mixed Pb‐Sn perovskite solar cells with significantly improved performance and stability are prepared by introducing an ionic imidazolium tetrafluoroborate additive. The synergistic effects of IM cation and tetrafluoroborate anion enable efficient defect passivation at grain boundaries, reducing leakage current, and enlargement in grain size with relaxed lattice strain simultaneously, thereby exerting a remarkable impact on device performance and stability.

Abstract

Narrow‐bandgap mixed Pb‐Sn perovskite solar cells (PSCs) have great feasibility for constructing efficient all‐perovskite tandem solar cells, in combination with wide‐bandgap lead halide PSCs. However, the power conversion efficiency of mixed Pb‐Sn PSCs still lags behind lead‐based counterparts. Here, additive engineering using ionic imidazolium tetrafluoroborate (IMBF₄) is proposed, where the imidazolium (IM) cation and tetrafluoroborate (BF₄) anion efficiently passivate defects at grain boundaries and improve crystallinity, simultaneously relaxing lattice strain, respectively. Defect passivation is achieved by the chemical interaction between the IM cation and the positively charged under‐coordinated Pb²⁺ or Sn²⁺ ions, and lattice strain relaxation is realized by lattice expansion with the intercalation of BF₄ anions into the perovskite lattice. As a result, the synergistic effects of the cation and anion in the IMBF₄ additive greatly enhance the optoelectronic performance of half‐mixed Pb‐Sn perovskites, leading to much longer carrier lifetimes. The best‐performing half‐mixed Pb‐Sn PSC shows an efficiency above 19% with negligible hysteresis, while retaining over 90% of its initial efficiency after 1000 h in a nitrogen‐filled glovebox and showing a lifetime to 80% degradation of 53.5 h under continuous illumination.

Publication date: April 2021

Source: Nano Energy, Volume 82

Author(s): Boer Tan, Sonia R. Raga, Kevin James Rietwyk, Jianfeng Lu, Sebastian O. Fürer, James C. Griffith, Yi-Bing Cheng, Udo Bach

Publication date: April 2021

Source: Nano Energy, Volume 82

Author(s): Narges Yaghoobi Nia, Mahmoud Zendehdel, Mojtaba Abdi-Jalebi, Luigi Angelo Castriotta, Felix U. Kosasih, Enrico Lamanna, Mohammad Mahdi Abolhasani, Zhaoxiang Zheng, Zahra Andaji-Garmaroudi, Kamal Asadi, Giorgio Divitini, Caterina Ducati, Richard H. Friend, Aldo Di Carlo

Publication date: April 2021

Source: Nano Energy, Volume 82

Author(s): Xinyu Yu, Zhen Li, Xianglang Sun, Cheng Zhong, Zonglong Zhu, Zhong’an Li, Alex K.-Y. Jen

Passive attack: The α‐FAPbI₃ perovskite layer in a solar cell is stabilized without deteriorating the spectral features by passivating with 2,3,4,5,6‐pentafluorobenzyl phosphonic acid (PFBPA). High‐quality perovskite solar cells with an improved efficiency of 22.25 % was achieved with excellent moisture stability maintaining >90 % of its initial efficiency at high humidity levels.

Abstract

Perovskite solar cells (PSCs) have shown great promise for photovoltaic applications, owing to their low‐cost assembly, exceptional performance, and low‐temperature solution processing. However, the advancement of PSCs towards commercialization requires improvements in efficiency and long‐term stability. The surface and grain boundaries of perovskite layer, as well as interfaces, are critical factors in determining the performance of the assembled cells. Defects, which are mainly located at perovskite surfaces, can trigger hysteresis, carrier recombination, and degradation, which diminish the power conversion efficiencies (PCEs) of the resultant cells. This study concerns the stabilization of the α‐FAPbI₃ perovskite phase without negatively affecting the spectral features by using 2,3,4,5,6‐pentafluorobenzyl phosphonic acid (PFBPA) as a passivation agent. Accordingly, high‐quality PSCs are attained with an improved PCE of 22.25 % and respectable cell parameters compared to the pristine cells without the passivation layer. The thin PFBPA passivation layer effectively protects the perovskite layer from moisture, resulting in better long‐term stability for unsealed PSCs, which maintain >90 % of the original efficiency under different humidity levels (40–75 %) after 600 h. PFBPA passivation is found to have a considerable impact in obtaining high‐quality and stable FAPbI₃ films to benefit both the efficiency and the stability of PSCs.

A novel strategy to neutralize charged point defects in organic‐inorganic hybrid perovskite materials is proposed for highly efficient and stable perovskite solar cells by using a zwitterionic L‐alanine additive, which can be passivated simultaneously with both positively and negatively charged defects because it contains both anion and cation functional groups in one molecule.

Abstract

Ionic defects (e.g., organic cations and halide anions), preferably residing along grain boundaries (GBs) and on perovskite film surfaces, are known to be a major source of the notorious environmental instability of perovskite solar cells (PeSCs). Although passivating ionic defects is desirable, previous approaches using Lewis base or acid molecules as additives suppress only the negatively or positively charged defects, thus leaving oppositely charged defects. In this work, both the cationic and anionic defects inside methyl ammonium lead tri‐iodide (MAPbI₃) are simultaneously passivated by introducing a zwitterionic form of the amino acid, L‐alanine, into the precursor solution as an additive. L‐alanine has both positive (NH₃ ⁺) and negative (COO⁻) functional groups at a specific solvent pH, thereby passivating both the cation and anion defects in MAPbI₃. The addition of L‐alanine increases the grain size of the perovskite crystals and lengthens the charge carrier lifetime (τ > 1 µs), leading to improved power conversion efficiencies (PCEs) of 20.3% (from 18.3% without an additive) for small‐area (4.64 mm²) devices and 15.6% (from 13.5%) for large‐area submodules (9.06 cm²). More importantly, the authors’ approach also significantly enhances the shelf storage and photoirradiation stabilities of PeSCs.

The moisture instability and unscalable fabrication protocols are still unsolved and blocking FACs‐based perovskite solar cells’ further applications. Here, high‐quality FACsPbI₃ films are fabricated by crown ether tailoring (which chelated with Cs⁺/Pb²⁺ ions) to inhibit the moisture invasion and stabilize the α‐phase FACsPbI₃, producing large‐area perovskite films and improving solar module performance.

Abstract

FACs‐based (FA⁺, formamidinium and Cs⁺, cesium) perovskite solar cells have gained great attention due to their remarkable light and thermal stabilities toward practical application of perovskite modules. However, the moisture instability and difficulty in scalable fabrication are still the main obstacles blocking their photovoltaic applications in current status. Here, the employment of novel interaction between crown ether with metal cations is introduced to tailor the uniform growth and inhibit moisture invasion during the crystallization of α‐phase FACsPbI₃, yielding the successful synthesis of high‐quality perovskite films in a large scale. Consequently, perovskite solar cells (PSC) modules in the total area of 4 × 4 and 10 × 10 cm² are readily fabricated with respective champion efficiencies of 16.69% and 13.84% and excellent stability over 1000 h. This facile scaling‐up strategy assisted by crown ether has shown great promise for pursuing efficient and highly stable large‐area PSC modules.

Bridge‐jointed 2D nanosheets are inserted between the methylammonium‐free perovskite and the dopant‐free hole transport layer (HTL) to form a scalable heterostructure, which preserves p‐type semiconduction of HTL and suppresses nonradiative‐recombination. Further, a perovskite solar module with an area of 35.80 cm² shows a certified efficiency of 15.3% and encapsulated modules retain over 91% of initial efficiency after damp heat test for 1000 h.

Abstract

Perovskite solar cell (PSC) modules employing a hole transport layer (HTL) without unstable dopants possess high potential for improving operational stability. However, the low efficiencies of the devices greatly limit their commercial applications owing to the lower efficacy of the dopant‐free HTL, introduced by the unintentional n‐doping effect of volatile ions from the halide‐rich perovskite surface. Here, a scalable heterostructure integrated by a methylammonium‐free perovskite film with an iodide‐rich surface, an ultrathin interlayer of bridge‐jointed graphene oxide nanosheets (BJ‐GO), and an HTL without additional ionic dopants is developed. In this heterostructure, the iodide ions are physically immobilized by the compact 2D network, and lead defects are chemically passivated by multiple coordination bonds. Moreover, the BJ‐GO with tunable surface energy enables a highly ordered HTL a considerably improved carrier mobility by an order of magnitude. Finally, the PSC module with an area of 35.80 cm² employing this heterostructure shows a certified efficiency of 15.3%. The encapsulated PSC modules retain over 91% of initial efficiency after the damp heat test at 85 °C and ≈85% relative humidity for 1000 h, while maintaining 90% of the initial value for 1000 h at the maximum power point under continuous 1‐Sun illumination at 60 °C.

We disclosed a key finding to modulate the crystallization kinetics of FASnI₃ through a non‐classical nucleation mechanism based on pre‐nucleation clusters. A direct link between the colloids in the perovskite precursor solution and final optoelectronic quality of the perovskite films was established. Finally, power conversion efficiency of 11.39 % was obtained for FASnI₃‐based perovskite solar cells.

Abstract

Tin halide perovskites are rising as promising materials for lead‐free perovskite solar cells (PSCs). However, the crystallization rate of tin halide perovskites is much faster than the lead‐based analogs, leading to more rampant trap states and lower efficiency. Here, we disclose a key finding to modulate the crystallization kinetics of FASnI₃ through a non‐classical nucleation mechanism based on pre‐nucleation clusters (PNCs). By introducing piperazine dihydriodide to tune the colloidal chemistry of the FASnI₃ perovskite precursor solution, stable clusters could be readily formed in the solution before nucleation. These pre‐nucleation clusters act as intermediate phase and thus can reduce the energy barrier for the perovskite nucleation, resulting in a high‐quality perovskite film with lower defect density. This PNCs‐based method has led to a conspicuous photovoltaic performance improvement for FASnI₃‐based PSCs, delivering an impressive efficiency of 11.39 % plus improved stability.

Metal (titanium or Ti) nanopillar arrays (NaPAs), vertically protruding on a TiO₂ compact layer, function as an electron transporting layer in perovskite solar cells. Ti NaPA has highly hydrophilic surfaces passivated with TiO₂, high electron mobility, and low work function; hence it compensates the loss of light harvesting in perovskite and leads to highly efficient, antiaging photovoltaic performance.

Abstract

Electron transporting layers (ETLs), required to be optically transparent in perovskite solar cells (PSCs) having regular structures, possess a determinant effect on electron extraction and collection. Metal oxides (e.g., TiO₂) have overwhelmingly served as ETLs, but usually have low electron mobility (μ_e < 10⁻² cm² V⁻¹ s⁻¹) not favorable for photovoltaic conversion. Here, metal oxides are replaced with metals (e.g., Ti with μ_e ≈ 294 cm² V⁻¹ s⁻¹) that are sculptured via glancing angle deposition to be a close‐packed nanopillar array (NaPA), which vertically protrudes on a transparent electrode to obtain sufficient optical transmission for light harvesting in perovskite. Ti NaPAs, whose rough surfaces are passivated with 5 nm thick TiO₂ (i.e., Ti NaPAs@TiO₂) to suppress exciton recombination, lead to the champion power conversion efficiency (PCE) of 18.89% that is superior to that of MAPbI₃ PSCs without Ti NaPAs@TiO₂ or containing TiO₂ NaPAs@TiO₂, owing to high surface wettability, high μ_e, and relatively low work function of Ti. Furthermore, Ti NaPAs@TiO₂ effectively prevents the decomposition of MAPbI₃ to achieve long‐term shelf stability whereby 50‐day aging only causes 15% PCE degradation. This work paves the way toward widening the material spectrum, from semiconductors to metals, to generate a diverse range of ETLs for producing efficient optoelectronic devices with long‐term shelf stability.

High‐quality and all‐inorganic CsPbI₂Br perovskite film with lower defects and improved hydrophobicity is prepared via a facile additive engineering with trace S₈, resulting in inverted solar cells with improved efficiency and stability.

Though prized for excellent thermal stability, inorganic perovskites are still behind organic/inorganic hybrid perovskites due to their high‐density defects and poor hydrophobicity. Herein, trace hydrophobic S₈ is used as additive to optimize the solution‐processed CsPbI₂Br perovskite film. A series of characterizations reveal that S₈ additive not only leads to retarded crystallization of α‐CsPbI₂Br perovskite at low temperature (<150 °C) via self‐formed Pb(S₈) _x ²⁺ intermediate but also induces efficient grain‐boundary passivation via distinctive PbS coordination interaction and reduced wettability on perovskite surface, which all point to the formation of the perovskite film with reduced defects and improved hydrophobicity. As a result, the inverted perovskite solar cells (PSCs) based on the optimized all‐inorganic perovskite of CsPbI₂Br:S₈ deliver an increased power conversion efficiency (PCE) from 12.76% to 14.46% as well as remarkably enhanced device stability under thermal or ambient condition. This work thus provides a simple way as well as new insights for boosting the performance of solution‐processed all‐inorganic perovskite.

Strain widely exists in metal–halide perovskites (MHPs), and the presence of the residual strain greatly influences the optoelectronic properties of MHP film. Recently, many studies have reported the key role of strain engineering in improving the photovoltaic performance of perovskite solar cells (PSCs). Herein, current understanding and advanced strategies of strain engineering in PSCs are systematically summarized.

Due to the impressive optoelectronic properties, metal–halide perovskites (MHPs) have drawn much attention in the field of next‐generation photovoltaics, and perovskite solar cells (PSCs) based on MHPs as light absorbers have reached a certified power conversion efficiency (PCE) of 25.5% in 2020. Despite the great progress, it is still challenging to fabricate high‐quality MHP films. Due to the “soft” ionic nature of MHPs, their polycrystalline films suffer from inevitable residual strain, which is found to not only be fatal to photovoltaic performance of PSCs, but also seriously accelerate the degradation of MHP film. As a result, understanding of strain in MHPs and the key role of strain engineering in improving the photovoltaic performance of PSCs have recently been extensively investigated. Herein, the recent progress of strain engineering in MHPs and their PSCs is systematically summarized. First, the origin of strain in MHPs and the impact of strain on the optoelectronic characteristics of MHPs are carefully discussed. Thereafter, the up‐to‐date studies focusing on strain engineering in PSCs are comprehensively reviewed. At last, the current challenges and future prospects in this field are highlighted.

Perovskite solar cells (PSCs) have debuted as the photovoltaic devices with the most potential and progress is being made at an unprecedented pace. Meanwhile, additive engineering is continuously pushing the power conversion efficiency (PCE) and device stability to higher levels by passivating defects and regulating crystallization behaviors. Considering the scalable fabrication of PSCs in the following stage, seeking green additives for optimizing perovskites is extremely valuable and paramount. Herein, we pioneer a green additive engineering method using fumaric acid (FMAC) to optimize the three‐cation perovskites in order to obtain highly efficient PSCs. FMAC not only optimizes crystallization behaviors to endow the perovskite films with large grain size and few grain boundaries, but also forms a strong interaction with Pb²⁺/I⁻ of the perovskites, thereby stabilizing the [PbI₆]⁴⁻ octahedral framework of the perovskite crystal lattices and effectively passivating the surface defects. On this basis, FMAC improves the photoelectric properties of perovskites and in particular, suppresses the non‐radiative recombination. Consequently, the PCE of PSCs incorporating FMAC rises to 20.48%, exceeding that (19.18%) of the pristine device. In addition, FMAC also enhances the stability of PSCs. Therefore, we provide a significant strategy using a green additive to enhance the photovoltaic performance of PSCs.

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