Chen Weijie

Publication date: September 2024

Source: Journal of Energy Chemistry, Volume 96

Author(s): Hang Yang, Tao Zhou, Haoyu Cai, Wenjian Shen, Hao Chen, Yongjun Liu, Juan Zhao, Yi-Bing Cheng, Jie Zhong

In the mixed phase of quasi-2D perovskite, formamidinium (FA) prefers to incorporate into the larger n value phases nearby the film surface compared to the smaller n value phases in the bulk, resulting in a narrow bandgap and gradient structure within the film. Based on this, the power conversion efficiency of the device reaches 18.58% after the introduction of 10% FA ions.

Abstract

Quasi-2D perovskites have attracted much attention in perovskite photovoltaics due to their excellent stability. However, their photoelectric conversion efficiency (PCE) still lags 3D counterparts, particularly with high short-circuit current (J _SC) loss. The quantum confinement effect is pointed out to be the sole reason, which introduces widened bandgap and poor exciton dissociation, and undermines the light capture and charge transport. Here, the gradient incorporation of formamidinium (FA) cations into quasi-2D perovskite is proposed to address this issue. It is observed that FA prefers to incorporate into the larger n value phases near the film surface compared to the smaller n value phases in the bulk, resulting in a narrow bandgap and gradient structure within the film. Through charge dynamic analysis using in situ light-dark Kelvin probe force microscopy and transient absorption spectroscopy, it is demonstrated that incorporating 10% FA significantly facilitates efficient charge transfer between low n-value phases in the bulk and high n-value nearby film surface, leading to reduced charge accumulation. Ultimately, the device based on (AA)₂(MA_0.9FA_0.1)₄Pb₅I₁₆, where AA represents n-amylamine renowned for its exceptional environmental stability as a bulky organic ligand, achieves an impressive power conversion efficiency (PCE) of 18.58% and demonstrates enhanced illumination and thermal stability.

Herein, an inorganic-based cesium (Cs) dopant is introduced to modify the SnO₂ ETL and to investigate its impact in curing interfacial defects, and charge-carrier dynamics of PSCs. The incorporation of Cs contents efficiently improves the perovskite film quality by enhancing the transparency, crystallinity, grain size, and light absorption and reducing the defect states and trap densities, resulting in an improved PCE of 22.1% with a remarkable environmental stability in a relatively higher relative humidity environment (>65%) and without encapsulation.

Abstract

A high-quality nanostructured tin oxide (SnO₂) has garnered massive attention as an electron transport layer (ETL) for efficient perovskite solar cells (PSCs). SnO₂ is considered the most effective alternative to titanium oxide (TiO₂) as ETL because of its low-temperature processing and promising optical and electrical characteristics. However, some essential modifications are still required to further improve the intrinsic characteristics of SnO₂, such as mismatch band alignments, charge extraction, transportation, conductivity, and interfacial recombination losses. Herein, an inorganic-based cesium (Cs) dopant is used to modify the SnO₂ ETL and to investigate the impact of Cs-dopant in curing interfacial defects, charge-carrier dynamics, and improving the optoelectronic characteristics of PSCs. The incorporation of Cs contents efficiently improves the perovskite film quality by enhancing the transparency, crystallinity, grain size, and light absorption and reduces the defect states and trap densities, resulting in an improved power conversion efficiency (PCE) of ≈22.1% with Cs:SnO₂ ETL, in-contrast to pristine SnO₂-based PSCs (20.23%). Moreover, the Cs-modified SnO₂-based PSCs exhibit remarkable environmental stability in a relatively higher relative humidity environment (>65%) and without encapsulation. Therefore, this work suggests that Cs-doped SnO₂ is a highly favorable electron extraction material for preparing highly efficient and air-stable planar PSCs.

To develop redshifted dimeric acceptors, multi-selenophene strategies are adopted to deliver DYSe-1 and DYSe-2 for the first time. Due to their effective absorption extending to ≈920 nm and reduced energy losses, DYSe-1 and DYSe-2-based organic solar cells exhibit outstanding short-circuit current density over 27 mA cm⁻², resulting in their promising power conversion efficiencies of 18.56% and 18.22%, respectively.

Abstract

Dimeric acceptor (DMA) becomes a promising alternative to small-molecular and polymeric acceptor-based organic solar cells (OSCs) due to its well-defined chemical structure, high batch-to-batch reproducibility, and low molecular diffusion properties. However, DMAs usually exhibit blueshifted absorptions, limiting their photon utilization abilities. Herein, multi-selenophene strategies are adopted to develop redshifted DMAs. From monomer (YSe) to dimers (DYSe-1 and DYSe-2), reduced electron reorganization energies and exciton binding energies enable the efficient charge dynamics in the DMAs-based OSCs. Together with their effective absorption extending to ≈920 nm, DYSe-1- and DYSe-2- based OSCs exhibit outstanding short-circuit current densities (J _SCs) over 27 mA cm⁻², which are the best among DMAs. Besides, compared with the YSe-based device, both DMA-based devices have higher electroluminescence quantum efficiencies and thus reduce nonradiative recombination loss (ΔE₃), contributing to their reduced energy losses. The resultant open-circuit voltages (V _OCs) of DYSe-1- and DYSe-2- based OSCs are ≈0.88 V, which, combining their super J _SC values, lead to the promising power conversion efficiencies of 18.56% and 18.22%, respectively. These results are among the best in DMAs-based OSCs and highlight the great potential of the multi-selenophene strategy for the development of redshifted DMAs with high performance.

Employing a crosslinked molecule with three stereoscopic crosslink sites, pentaerythritol triacrylate, to establish a stereoscopic polymer network in both interface and bulk perovskite. This network effectively reduces cracks and delamination in flexible devices under high mechanical stress. Consequently, the cell retained 92% of its initial power conversion efficiency (PCE) after 20,000 bending cycles, and demonstrated a record PCE of 24.9%.

Abstract

Flexible perovskite solar cells (pero-SCs) have the potential to overturn the application scenario of silicon photovoltaic technology. However, their mechanical instability severely impedes their practical applicability, and the corresponding intrinsic degradation mechanism remains unclear. In this study, the degradation behavior of flexible pero-SCs is systematically analyzed under mechanical stress and it is observed that the structural failure first occurs in the polycrystal perovskite film, then extend to interfaces. To suppress the structural failure, pentaerythritol triacrylate, a crosslinked molecule with three stereoscopic crosslink sites, is employed to establish a 3D polymer network in both the interface and bulk perovskite. This network reduced the Young's modulus of the perovskite and simultaneously enhanced the interfacial toughness. As a result, the formation of cracks and delamination, which occur under a high mechanical stress, is significantly suppressed in the flexible pero-SC, which consequently retained 92% of its initial power conversion efficiency (PCE) after 20 000 bending cycles. Notably, the flexible device also shows a record PCE of 24.9% (certified 24.48%).

The interaction between perovskite decomposition products and indium tin oxide substrate triggers positive feedback cycle and deteriorates the stability of perovskite solar cell.

Abstract

Stability is the most pressing challenge hindering the commercialization of perovskite solar cells (PSCs), and previous efforts focused more on enhancing the resistance of PSCs to external stimulus. Here, we found that the indium tin oxide (ITO) will deteriorate the photovoltaic performance of PSCs through positive feedback cycles. Specifically, the perovskite degradation products will cross the electron transport layer to chemically etch the electrode ITO to generate In³⁺, which will migrate upwards into the perovskite film. Then, the reaction that corrodes ITO consumes the decomposition products of perovskite and shifts the balance of the perovskite decomposition reaction, further promoting the degradation and thus falling into a positive feedback cycle. Moreover, the In³⁺ in the perovskite film was found to accumulate at the upper surface, which would lead to n-type doping of perovskite film to form the energy barrier for interface carrier extraction. Subsequently, the chelating molecule ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) was introduced onto ITO to firmly chelate the In³⁺ and prevent it from migrating upward, thus breaking this internal positive feedback cycle and significantly enhancing the efficiency and stability of PSCs. This work provides new perspectives for understanding the mechanism of photovoltaic performance loss and ionic transport in PSCs.

By introducing DFA additive into perovskite solution and interacting with DMSO, DTE and DA products were obtained. The strong bonding DTE⋅PbI₂ and DA⋅PbI₂ retard perovskite crystallization process for high-quality and low defects perovskite film. Finally, a champion PCE of 25.28 % was achieved with excellent environmental stability, which retained 95.75 % of the initial PCE after 1152 h at 25 °C under 25 % RH.

Abstract

It is a crucial role for enhancing the power conversion efficiency (PCE) of perovskite solar cells (PSCs) to prepare high-quality perovskite films, which can be achieved by delaying the crystallization of perovskite film. Hence, we designed difluoroacetic anhydride (DFA) as an additive to regulating crystallization process thus reducing defect formation during perovskite film formation. It was found DFA reacts with DMSO by forming two molecules, difluoroacetate thioether ester (DTE) and difluoroacetic acid (DA). The strong bonding DTE⋅PbI₂ and DA⋅PbI₂ retard perovskite crystallization process for high-quality film formation, which was monitored through in situ UV/Vis and PL tests. By using DFA additives, we prepared perovskite films with high-quality and low defects. Finally, a champion PCE of 25.28 % was achieved with excellent environmental stability, which retained 95.75 % of the initial PCE after 1152 h at 25 °C under 25 % RH.

Nature Communications, Published online: 11 May 2024; doi:10.1038/s41467-024-48518-4

Publication date: September 2024

Source: Journal of Energy Chemistry, Volume 96

Author(s): Xiangbao Yuan, Xufeng Ling, Hongyu Wang, Chengxia Shen, Ru Li, Yehao Deng, Shijian Chen

PenAAc is used to optimize the interface between Sn–Pb perovskite and PEDOT:PSS. Both theoretical and experimental studies reveal that PenA⁺ and Ac⁻ can decrease defect states at the interface and strengthen the binding between PEDOT:PSS and Sn–Pb perovskite. With the PenAAc buried layer, the performance of the Sn–Pb single-junction and all-perovskite tandem solar cells are significantly improved.

All-perovskite tandem solar cells (ATSCs) present a remarkable opportunity to overcome the Shockley–Queisser efficiency limit of single-junction solar cells. However, the stability of ATSCs significantly lags that of their pure Pb-based single-junction counterparts. Recent studies have identified that the widely used poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) hole transport layer in narrow-bandgap (NBG) tin–lead (Sn–Pb) perovskite solar cells (PSCs) hinders the efficiency and stability. Herein, a patching strategy to optimize the interface between perovskite and PEDOT:PSS is proposed. Both theoretical and experimental studies reveal that PenA⁺ and Ac⁻ can decrease defect states at the interface and strengthen the binding between PEDOT:PSS and Sn–Pb perovskite. Furthermore, the pentylammonium acetate (PenAAc) interlayer improves carrier extraction and suppresses the oxidation of Sn²⁺ to Sn⁴⁺. With the PenAAc buried layer, the fabricated NBG PSCs obtain an impressive power conversion efficiency (PCE) of 21.86%, along with significantly enhanced device stability. By integrating the buried passivated NBG Sn–Pb perovskite with a 1.75 eV wide-bandgap PSC, the two-terminal ATSC achieves a PCE of 26.54%. This work provides a valuable approach to fabricate efficient and stable NBG PSCs.

High quality CsPbI₂Br film is achieved though crystallization regulation by introducing a metastable lewis acid-base adduct of PbX₂-TBP. Preferential decomposition of such adducts at low temperature annealing leads to formation of perovskite seeds, followed by crystal growth assisted by PbX₂-DMSO. PSCs constructed with the optimized CsPbI₂Br film demonstrate a remarkable PCE of 16.5%, with an impressive V _OC reaching 1.3 V.

Abstract

All inorganic perovskite based on CsPbI₂Br has attracted significant attention due to its relatively thermal stable structure compare to its hybrid counterparts. With a wide bandgap of 1.9 eV and excellent light absorption capability, it has been extensively explored for applications in indoor photovoltaics and as a front absorber in tandem devices. However, the uncontrollable crystallization process during solvent evaporation and thermal annealing leads to both macroscopic defects like cracks and microscopic defects such as voids. In this study, a metastable adduct with lead (II) halides by incorporating 4-tert-butyl pyridine as a volatile Lewis base monodentate ligand in the precursor solution is formed. The strategic preferential decomposition of the adduct during the early-stage low-temperature annealing facilitated the desorption of lead (II) halides, inducing antisolvent-free heterogenous nucleation. This, in turn, promoted crystal growth during subsequent high-temperature annealing, resulting in dense films with low defect density. As a result, a maximum open-circuit voltage of 1.30 V is achieved with the champion power conversion efficiency of 16.5% in CsPbI₂Br-based perovskite solar cell. The work reveals a new mechanism of using Lewis acid-base adduct to obtain high quality perovskite films other than hindering crystallization in traditional way.

A novel 3D hole transporting material termed FTPE-ST is reported, which has a large conjugated structure leading to high hole mobility, and sulfur atoms that can bind to coordinately unsaturated lead centers on the surface of perovskite films, enhancing interfacial interactions. Perovskite solar cells and modules incorporating FTPE-ST achieve power conversion efficiencies of 25.21 and 21.27%, respectively.

Abstract

The orthogonal structure of the widely used hole transporting material (HTM) 2,2′,7,7′-tetrakis(N, N-di-p-methoxyphenylamino)−9,9′-spirobifluorene (Spiro-OMeTAD) imparts isotropic conductivity and excellent film-forming capability. However, inherently weak intra- and inter-molecular π–π interactions result in low intrinsic hole mobility. Herein, a novel HTM, termed FTPE-ST, with a twist conjugated dibenzo(g,p)chrysene core and coplanar 3,4-ethylenedioxythiophene (EDOT) as extended donor units, is designed to enhance π–π interactions, without compromising on solubility. The three-dimensional (3D) configuration provides the material multi-direction charge transport as well as excellent solubility even in 2-methylanisole, and its large conjugated backbone endows the HTM with a high hole mobility. Moreover, the sulfur donors in EDOT units coordinate with lead ions on the perovskite surface, leading to stronger interfacial interactions and the suppression of defects at the perovskite/HTM interface. As a result, perovskite solar cells (PSCs) employing FTPE-ST achieve a champion power conversion efficiency (PCE) of 25.21% with excellent long-time stability, one of the highest PCEs for non-spiro HTMs in n-i-p PSCs. In addition, the excellent film-forming capacity of the HTM enables the fabrication of FTPE-ST-based large-scale PSCs (1.0 cm²) and modules (29.0 cm²), which achieve PCEs of 24.21% (certificated 24.17%) and 21.27%, respectively.

Aminothiol hydrochlorides with different alkyl chains were employed to investigate the interplay between molecular structure, orientation, and interaction on perovskite surface. The 2-Aminoethane-1-thiol hydrochloride with shorter alkyl chains exhibited a preference of parallel orientation, enhancing its interaction with surface defects. Consequently, this led to the successful fabrication of a stable inverted device with an impressive PCE of 25 %.

Abstract

Nonradiative recombination losses occurring at the interface pose a significant obstacle to achieve high-efficiency perovskite solar cells (PSCs), particularly in inverted PSCs. Passivating surface defects using molecules with different functional groups represents one of the key strategies for enhancing PSCs efficiency. However, a lack of insight into the passivation orientation of molecules on the surface is a challenge for rational molecular design. In this study, aminothiol hydrochlorides with different alkyl chains but identical electron-donating (−SH) and electron-withdrawing (−NH₃ ⁺) groups were employed to investigate the interplay between molecular structure, orientation, and interaction on perovskite surface. The 2-Aminoethane-1-thiol hydrochloride with shorter alkyl chains exhibited a preference of parallel orientations, which facilitating stronger interactions with the surface defects through strong coordination and hydrogen bonding. The resultant perovskite films following defect passivation demonstrate reduced ion migration, inhibition of nonradiative recombination, and more n-type characteristics for efficient electron transfer. Consequently, an impressive power conversion efficiency of 25 % was achieved, maintaining 95 % of its initial efficiency after 500 hours of continuous maximum power point tracking.

4-T perovskite–CdSeTe tandem solar cells with an efficiency of more than 25% by tailoring transparent back contact and absorber bandgap of the perovskite cell are demonstrated. The analysis reveals a feasible pathway toward enhancing the efficiency of 4-T perovskite–CdSeTe tandems to over 30%.

Thin-film tandem photovoltaic (PV) technology has emerged as a promising avenue to enhance power conversion efficiency beyond the radiative efficiency limit of single-junction devices. Combining a tunable wide-bandgap perovskite cell with a commercially established narrow-bandgap cadmium selenium telluride (CdSeTe) cell in a comparatively easy-to-fabricate four-terminal (4-T) arrangement is a great step in that direction. Herein, the impact of the transparent back contact and the perovskite absorber bandgap on the performance of 4-T perovskite–CdSeTe tandem solar cells is investigated. 4-T perovskite–CdSeTe tandem device architecture with ≈25% efficiency is demonstrated and a feasible pathway is shown to improve the tandem efficiency to more than 30%. The results show that the integration of CdSeTe with perovskite in 4-T tandem PV configurations represents a significant advancement toward achieving higher efficiency and low-cost tandem PVs.

The S-shape in current density-voltage (J–V) characteristics of devices tested without Ultraviolet (UV) light activation is eliminated by the engineering of adsorbates on ZnO through increasing the annealing temperature and changing the recipe of ZnO. Increasing the content of O 1s at binding energy of 531 eV on ZnO in X-ray photoelectron spectroscopy can alleviate the need of UV light activation.

Ultraviolet (UV) light is typically needed to activate inverted organic photovoltaic (OPV) devices with zinc oxide (ZnO) as the electron transporting layer (ETL) for enhanced efficiency. Given that UV light may cause the degradation of active layers and interfaces, and considering the absence of UV light in typical indoor lighting, addressing the need of UV light activation for ZnO becomes paramount. Herein, the engineering of adsorbates on ZnO could solve this issue by increasing the annealing temperature and changing the recipe of ZnO. Increasing the content of O 1s at binding energy of 531 eV on ZnO in X-ray photoelectron spectroscopy would be beneficial to alleviate the need of UV light activation. For the (ZnO)_PEIE (zinc acetate dihydrate (ZAH) and polyethylenimine ethoxylated (PEIE) dissolved in 2-methoxyethanol, PEIE used to provide amine in the precursor), annealing at 180 °C would eliminated S-shape in the current density-voltage (J–V) characteristics without UV light activation. OPV modules (9.8 cm²) with 180 °C-annealed (ZnO)_PEIE as ETL achieved an efficiency of 18.2% under indoor lighting and 14.8%  under 1 sun with the UV filter (light intensity of 0.788 sun). These high efficiencies are achieved in the modules without the need for UV light activation.

In this research, three molecular additives are investigated that feature identical anions and branched functional groups. Through the integration of experimental data and Density Functional Theory (DFT), it is discovered that devices modified with TMAC achieve an outstanding PCE of 24.63%. Furthermore, TMAC-treated devices display exceptional operational stability, retaining over 93.13% of their initial efficiencies after 1200 h of continuous MPPT.

Abstract

In the commercial development of perovskite solar cells, the main challenge lies in achieving efficient devices with high stability. Additive engineering in polycrystalline perovskites is considered as an effective approach to address this challenge by passivating surface defects and reducing carrier losses associated with these defects. In this work, the passivation effect of molecules with different side chain groups on perovskites and the role of binding energy in mitigating carrier loss are studied. The findings reveal that the thiophene group is particularly effective in passivating defects and enhancing hole transport. Consequently, devices treated with 2-thienylmethylamine hydrochloride (TMAC) demonstrate a champion power conversion efficiency (PCE) of 24.63%. Furthermore, these TMAC-treated devices exhibit remarkable stability, maintaining over 93.13% of their initial efficiencies after 1200 h of continuous illumination under maximum power point tracking (MPPT). This research presents a pathway to enhance the optoelectronic performance and stability of perovskite solar cells.

Three new donor-acceptor-type interfacial dipole molecules are designed by incorporating hole transporting and different anchoring groups, which contributing to energy-level alignment, improved charge extraction and suppressed non-radiative recombination at the perovskite interface. TPA-BAM-treated PSCs achieve a champion efficiency of 25.29 % with the enhanced voltage of 1.174 V and fill factor of 84.34 %, while also demonstrating improved stability.

Abstract

Interfacial engineering of perovskite films has been the main strategies in improving the efficiency and stability of perovskite solar cells (PSCs). In this study, three new donor-acceptor (D–A)-type interfacial dipole (DAID) molecules with hole-transporting and different anchoring units are designed and employed in PSCs. The formation of interface dipoles by the DAID molecules on the perovskite film can efficiently modulate the energy level alignment, improve charge extraction, and reduce non-radiative recombination. Among the three DAID molecules, TPA-BAM with amide group exhibits the best chemical and optoelectrical properties, achieving a champion PCE of 25.29 % with the enhanced open-circuit voltage of 1.174 V and fill factor of 84.34 %, due to the reduced defect density and improved interfacial hole extraction. Meanwhile, the operational stability of the unencapsulated device has been significantly improved. Our study provides a prospect for rationalized screening of interfacial dipole materials for efficient and stable PSCs.

Lattice mismatch is crucial for the efficiency and lifetime of perovskite solar cells because it affects interfacial charge behavior and perovskite degradation. This review discusses the effects of lattice mismatch on strain, material stability, carrier dynamics, and detailed characterizations. It also exposes challenges to mitigate mismatch as well as a solution and outlook to promote renewable-energy-technology advancements.

Abstract

Lattice mismatch significantly influences microscopic transport in semiconducting devices, affecting interfacial charge behavior and device efficacy. This atomic-level disordering, often overlooked in previous research, is crucial for device efficiency and lifetime. Recent studies have highlighted emerging challenges related to lattice mismatch in perovskite solar cells, especially at heterojunctions, revealing issues like severe tensile stress, increased ion migration, and reduced carrier mobility. This review systematically discusses the effects of lattice mismatch on strain, material stability, and carrier dynamics. It also includes detailed characterizations of these phenomena and summarizes current strategies including epitaxial growth and buffer layer, as well as explores future solutions to mitigate mismatch-induced issues. We also provide the challenges and prospects for lattice mismatch, aiming to enhance the efficiency and stability of perovskite solar cells, and contribute to renewable energy technology advancements.

Publication date: 17 July 2024

Source: Joule, Volume 8, Issue 7

Author(s): Ahra Yi, Sangmin Chae, Hoang Mai Luong, Sung Hun Lee, Hanbin Lee, Haeun Yoon, Do-Hyung Kim, Hyo Jung Kim, Thuc-Quyen Nguyen

From theoretical simulation to experimental characterization, high-performance perovskite solar cells are achieved through the management of the electron-withdrawing groups in the side chain of hole transport materials.

Abstract

Management of functional groups in hole transporting materials (HTMs) is a feasible strategy to improve perovskite solar cells (PSCs) efficiency. Therefore, starting from the carbazole–diphenylamine-based JY7 molecule, JY8 and JY9 molecules are incorporated into the different electron-withdrawing groups of fluorine and cyano groups on the side chains. The theoretical results reveal that the introduction of electron-withdrawing groups of JY8 and JY9 can improve these highest occupied molecular orbital (HOMO) energy levels, intermolecular stacking arrangements, and stronger interface adsorption on the perovskite. Especially, the results of molecular dynamics (MD) indicate that the fluorinated JY8 molecule can yield a preferred surface orientation, which exhibits stronger interface adsorption on the perovskite. To validate the computational model, the JY7-JY9 are synthesized and assembled into PSC devices. Experimental results confirm that the HTMs of JY8 exhibit outstanding performance, such as high hole mobility, low defect density, and efficient hole extraction. Consequently, the PSC devices based on JY8 achieve a higher PCE than those of JY7 and JY9. This work highlights the management of the electron-withdrawing groups in HTMs to realize the goal of designing HTMs for the improvement of PSC efficiency.

The state-of-the-art PSCs employ α-FAPbI₃ in spite of its metastable crystalline phase at RT. In this review, the intrinsic structural stability of α-FAPbI₃ is discussed from the collective perspective based on various experimental results which are closely examined to understand fundamental origins and their role in maintaining the lattice structure, particularly by assessing the contribution between entropy and enthalpy term.

Abstract

Since the certified power conversion efficiency (PCE) of perovskite solar cells (PSCs) has reached 26.1%, exactly equal to that of crystalline silicon solar cells, a strong demand for ensuring the long-term stability of PSCs has arisen for commercialization. The intrinsic stability of the perovskite layer must be guaranteed as a top priority to ensure the whole device's stability. Recently, the state-of-the-art PSCs, performing a high PCE, employ α-FAPbI₃ (FA = formamidinium) for the perovskite layer in spite of its metastable tendency to spontaneously transform into its photoinactive polymorph at PSC operating temperature. In this review paper, the intrinsic structural stability of α-FAPbI₃ soft lattice is understood from the thermodynamic point of view, with key parameters to restrain the undesirable phase transition. Besides, reported experimental results are closely examined to find fundamental origins, derive the enhanced phase stability in each experiment, and understand their role in maintaining the lattice structure from the collective perspective.

A new polymer donor PQSe-TCl is synthesized to investigate the film-formation kinetics and resultant morphologies of nfEAs-based organic photovoltaic cells. The PQSe-TCl:4T-16-based device achieves an outstanding PCE of 16.9%, which is the highest value of fully nfEA-based organic photovoltaic cells.

Abstract

Organic photovoltaic cells (OPVs) based on non-fused electron acceptors (nfEAs) have exhibited substantial progress in enhancing the power conversion efficiency (PCE). However, controlling the morphology of the donor/acceptor blend remains a significant challenge, making the regulation of film formation kinetics crucial. Here, by designing a new selenium-containing polymer donor PQSe-TCl, the pre-aggregation behavior is modulated and finely tune the resultant morphologies. Compared with its thiophene analogue PBQx-TCl, PQSe-TCl exhibits a larger π–π stacking distance and weaker pre-aggregation performance, leading to a longer film-formation duration in the fabrication process. Consequently, the PQSe-TCl:A4T-16-based device records an outstanding PCE of 16.9%, which is the highest value for fully nfEA-based OPVs. This study highlights the importance of regulating the film-formation kinetics for obtaining high-efficiency nfEA-based OPVs.

Perovskite solar cells (PSCs) show promise for space use, but overcoming low performance and long-term stability challenges in the harsh space environment is essential. This review discusses the impact of the extreme space environment on PSCs and recent developments and challenges related to perovskite tandem solar cells for achieving high-performance PSCs in space applications.

Abstract

The rapid advancement of next-generation wireless communication technology based on satellite communication using tens of thousands of low Earth orbit (LEO) satellites requires higher technology for solar energy systems. The perovskite solar cells (PSCs) show great potential as modern space solar cells due to high power, high specific power, high radiation resistance, and low cost compared to conventional space solar cells, such as III-V and Si solar cells. However, the study of PSCs has been almost focused on terrestrial use for commercialization, thereby a few research for PSCs as space solar cells. This review discusses the current progress and future challenges for the space application of PSCs. To understand the space applications, the extreme space environmental conditions are summarized and their impacts on PSCs. Notably, the two-terminal (2T) monolithic perovskite-based tandem solar cells (PTSCs) capable of high performance with high efficiency and specific power are discussed. Finally, the key technology and the perspectives for the future development of PSCs are suggested for practical use as space applications.

Publication date: September 2024

Source: Journal of Energy Chemistry, Volume 96

Author(s): Hang Yang, Jianhong Zhao, Xiaodong Ren, Tong Zhou, Henbing Zhang, Weilong Zhang, Jin Zhang, Guangzhi Hu, Yuming Zhang, Wen-Hua Zhang, Qingju Liu

We report the intercalation of an amino acid molecular modulator, hydroxylamine-O-sulfonic acid (HOSA) for perovskite photoabsorbers  in high performance perovskite solar cell. HOSA endowing both -SO₃H and -NH₂ functional moieties forming strong interactions with uncoordinated Pb²⁺ and I⁻ defects, respectively, resulting in improvement in photovoltaic performance and stability against elevated temperature.

Despite the rapid development of perovskite solar cells (PSCs), defects in the devices continue to impede further improvements in power conversion efficiency and operational stability. In this work, the use of hydroxylamine-O-sulfonic acid as a bifunctional molecule to enhance the performance of PSCs is described. Strong coordination exists between the sulfonic acid group and uncoordinated Pb²⁺ of perovskite, while the NH bond on amino group interacts with uncoordinated I⁻. Thus, due to the synergistic contribution of sulfonic acid group and amino groups, the high-quality perovskite film with good crystallinity and low defect density is achieved. As a result, the optimal devices exhibit an enhanced efficiency of 23.33%, which is much higher than that of the control device (21.53%). Notably, the optimized target device exhibits excellent long-term operational stability, retaining over 90% of its initial efficiency after 480 h at 65 °C, over 93% after a continuous illumination test for 650 h, and over 96% after nearly 1400 h of air storage. In contrast, the control device demonstrates poorer stability. In these results, it is suggested that selecting a dual-functional additive is a promising approach to enhance efficiency and maintain stability in PSCs.