This work discusses the need to enhance charge carrier collection to minimize halide segregation in wide band-gap (WBG) perovskites. Here, we systematically elucidate the impact of valence band maximum (VBM) offsets and energetic barriers formed at the hole transport layer (HTL)/perovskite interface on charge accumulation, its influence on halide segregation, and ultimately on perovskite solar cell (PSC) long-term photostability. To this end, we precisely tune the VBM-HTL energetic levels by employing blends of self-assembled monolayers (SAMs; MeO-2PACz and Br-2PACz) to fabricate customized HTLs for PSCs with three different WBG perovskite photoabsorbers (1.69, 1.81, and 2.00 eV), commonly used in various tandem configurations. We find that optimized energetic alignment at the SAM HTL/perovskite interface significantly enhances the long-term photostability of the WBG PSCs. Our results show that photostability of devices can be predicted when comparing HTL/perovskite interfaces using photoluminescence’s evolution and transient surface photovoltage spectroscopies of half-stacks (glass/metal oxide/HTL/perovskite) in correlation with halide segregation.

中文翻译：

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空穴收集界面价带能量排列对宽带隙钙钛矿太阳能电池光稳定性的影响


这项工作讨论了增强载流子收集的必要性，以最大限度地减少宽带隙（WBG）钙钛矿中的卤化物偏析。在这里，我们系统地阐明了价带最大值（VBM）偏移和空穴传输层（HTL）/钙钛矿界面处形成的能量势垒对电荷积累的影响，其对卤化物偏析的影响，以及最终对钙钛矿太阳能电池（PSC）的影响长期光稳定性。为此，我们通过采用自组装单分子层（SAM、MeO-2PACz 和 Br-2PACz）的混合物来精确调整 VBM-HTL 的能量水平，为具有三种不同 WBG 钙钛矿光吸收剂（1.69、1.81 和 1.69、1.81 和2.00 eV），常用于各种串联配置。我们发现 SAM HTL/钙钛矿界面处的优化能量排列显着增强了 WBG PSC 的长期光稳定性。我们的结果表明，当使用半堆（玻璃/金属氧化物/HTL/钙钛矿）的光致发光演化和瞬态表面光电压光谱与卤化物偏析相关来比较HTL/钙钛矿界面时，可以预测器件的光稳定性。