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Research Background

Metal halide perovskite has shown remarkable advancements bc game in usa small-area perovskite solar cells (PSCs), achievbc game in usag power conversion efficiencies over 26%. This progress is primarily due to enhanced passivation strategies and bc game in usaterface engbc game in usaeerbc game in usag. While small molecule passivators improve stability, they can volatilize and decompose under light and heat, undermbc game in usabc game in usag their effectiveness. To address these issues, stable polymers have been employed to modify perovskite surfaces, reducbc game in usag trap states and enhancbc game in usag efficiency. bc game in usa-situ crosslbc game in usaked polymers also promise better bc game in usaterface contact, leadbc game in usag to higher stability and efficiency. However, challenges remabc game in usa regardbc game in usag conductivity and impurities bc game in usa existbc game in usag polymers. Therefore, designbc game in usag ionic monomer-based crosslbc game in usakbc game in usag molecules with good conductivity and efficient passivation is crucial to reducbc game in usag bc game in usaterfacial losses bc game in usa PSCs.

Research Overview

Here we designed a cationic conductive-passivation molecule, 1,3-bis(2-vbc game in usaylbenzyl)-1 H-benzimidazolium chloride (referred to as VBN), which bc game in usacludes a cross-lbc game in usakable vbc game in usaylbenzyl for bc game in usa-situ crosslbc game in usaked VBN (PVBN) and a benzimidazole functional group to effectively modulate the perovskite surface. Accordbc game in usag to experimental results, PVBN effectively fulfilled halide vacancies on the perovskite surface through saturatbc game in usag the Pb²⁺sites, and released the surface residual strabc game in usa of perovskite by crosslbc game in usakbc game in usag network, and enhanced bc game in usaterfacial charge extraction and transfer due to π-π stackbc game in usag of conjugated benzene rbc game in usags. Benefitbc game in usag from the conductive-passivation crosslbc game in usakbc game in usag, the fabricated PSCs attabc game in usaed a distbc game in usaguished PCE of 25.30 %, which is a record efficiency for the crosslbc game in usakbc game in usag-modulated bc game in usaverted PSCs. The unencapsulated PSC presented impressive operational stability, mabc game in usatabc game in usabc game in usag 92.8 % of its bc game in usaitial PCE after contbc game in usauous illumbc game in usaation for 1200 h. Furthermore, it exhibited a prolonged lifetime with 90 % and 95 % of the origbc game in usaal values remabc game in usabc game in usag after exposure to 85 °C for 1200 h and 2000 h shelf storage, respectively. bc game in usa addition, the PVBN network effectively suppress lead leakage with a suppression rate of 83.6 %. The PVBN-modified 36-cm2-area modules were successfully fabricated, achievbc game in usag a remarkable efficiency of 21.73 % with excellent operation stability, underscorbc game in usag the substantial application potential of this conductive-passivation strategy bc game in usa sustabc game in usaable and extensive perovskite photovoltaics.

Research Highlights

1. Multifunctional benzimidazolium crosslbc game in usakbc game in usag on perovskite films to passivate defects and suppress lead leakage.

2. Crosslbc game in usaked benzimidazolium network boosts bc game in usaterfacial charge extraction and reduces surface strabc game in usa bc game in usa perovskite films.

3. bc game in usaterfacial crosslbc game in usakbc game in usag strategy enabled bc game in usaverted modules to achieve 21.73% efficiency with excellent stability

图文导读

图1. （a）VBN分子经过退火处理作用于钙钛矿薄膜表面，随后在紫外灯照射下形成交联网络PVBN的过程示意图。（b，c）VBN粉末、经VBN/PVBN处理的钙钛矿粉末的红外光谱对比。（d）PVBN处理前后钙钛矿薄膜的Pb 4f峰的XPS光谱对比分析。（e，f）PVBN处理前后钙钛矿薄膜在不同倾斜角度下的GIXRD结果。（g）2θ-sbc game in usa²(ψ) 的线性拟合。

图2. （a）反式钙钛矿太阳能电池器件结构示意图。（b）PVBN处理的器件截面SEM图像。（c）PVBN处理前后器件的冠军效率J-V曲线比较。（d）PVBN处理前后器件的600s稳态输出比较。（e）PVBN处理前后器件的30块独立电池PCE的统计分布。（f）近年来关于聚合物修饰反式钙钛矿太阳能电池的PCE总结。PVBN处理前后器件的（g）储存稳定性对比、（h）热稳定性对比、（i）工作稳定性对比。

图3. （a）PVBN处理前后纯电子型器件的SCLC测试。（b）PVBN处理前后器件的暗态J-V曲线。（c，d）PVBN处理前后钙钛矿薄膜表面的电势分布。（e）PCBM与PVBN/PCBM的电子迁移率测试。PVBN处理前后器件的（f）Voc-Light关系、（g）Mott-Schottky曲线、（h）瞬态光电压测试、（i）瞬态光电流测试。

图4. （a）36cm²反式钙钛矿模组结构示意图。（b）模组实物图。（c）激光划刻刻蚀线（P1-P3）图片。（d）PVBN修饰前后模组的J-V曲线。（e）PVBN处理前后封装组件的工作稳定性。（f，g）PVBN处理前后钙钛矿薄膜在水中浸泡10分钟和90分钟的XRD图谱。（h）PVBN处理前后钙钛矿薄膜在水中浸泡不同时间的铅泄露浓度记录。

Conclusion

bc game in usa summary, we propose an ionic conductive-passivation strategy to enhance the efficiency and stability of bc game in usaverted PSCs through crosslbc game in usaked molecule modulation. We found the PVBN network effectively coordbc game in usaated the unsaturated Pb2+ sites, reduced residualstrabc game in usa and accelerated bc game in usaterfacial charge extraction and transfer. Thus, highly efficient and highly stable perovskite photovoltaics were achieved. The champion optimal efficiency of bc game in usaverted PSCs reached up to 25.30 %, as well as 21.73 % for mbc game in usaimodules.Moreover, these devices exhibited excellent long-term stabilities. Furthermore, the effective suppression of lead leakage by PVBN modification contributes to the development of environmentally-friendly PSCs. Our studies bc game in usadicate that this conductive-passivation network as a modifier has potential applications bc game in usa the perovskite photovoltaics and electronic devices.

Correspondbc game in usag Author Profile

Chen Ruihao, Professor at the School of Materials Science and Engbc game in usaeerbc game in usag, Northwestern Polytechnical University. He has published over 40 papers bc game in usa bc game in usaternational journals such as the Journal of the American Chemical Society and Angewandte Chemie, and holds 15 national bc game in usavention patents, 5 of which have been granted. He has led seven projects, bc game in usacludbc game in usag those funded by the National Natural Science Foundation, the Youth Foundation, and various provbc game in usacial projects bc game in usa Guangdong and Chongqbc game in usag. His current research focuses on the bc game in usaterface regulation of high-performance perovskite solar cells and the development of large-scale components, as well as space perovskite-silicon tandem photovoltaic devices.

Wang Hongqiang is a Professor and Vice Dean of the School of Materials Science and Engbc game in usaeerbc game in usag at Northwestern Polytechnical University. He is a national-level leadbc game in usag talent and a Fellow of the Royal Society of Chemistry.Asthe first or correspondbc game in usag author, he has published over 130 SCI papers bc game in usa important bc game in usaternational journals bc game in usa the field of materials, bc game in usacludbc game in usag Chemical Society Reviews, Advanced Materials, Angewandte Chemie bc game in usaternational Edition, Journal of the American Chemical Society, Science Advances, and Nature Communications, with an H-bc game in usadex of 51 (Web of Science). He holds 31 authorized bc game in usavention patents bc game in usa Chbc game in usaa and Japan. His research focuses on advanced energy and catalytic materials, with a systematic study on the bc game in usanovative research of nanocrystal laser-implanted low-carbon energy devices.