Perovskite surface passivation is key to eliminating junction charge-carrier losses and is considered a critical step in fabricating solar cells with efficiencies close to the theoretical limit. Various halogenated organic ligands are found to produce efficient and stable solar cells when the perovskite surfaces are thermally activated. Photoemission spectroscopy shows that most of the ligands start to evaporate during heating. When annealed at high temperatures, halogens are cleaved off the ligands, leaving the organic cations anchored to the perovskite and causing charge transfer n-doping. The band-alignment measurement reveals that the formation of n-doped perovskites caused by strongly anchored ligands leads to the formation of ideal heterojunctions with energy offsets benefiting electron extraction and hole blocking, contributing to over 22% improvement in device performance without burn-in degradation.

中文翻译：

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钙钛矿表面卤素裂解有机配体的锚定

钙钛矿表面钝化是消除结载流子损失的关键，被认为是制造效率接近理论极限的太阳能电池的关键步骤。当钙钛矿表面被热激活时，发现各种卤代有机配体可以产生高效且稳定的太阳能电池。光电子能谱显示大部分配体在加热过程中开始蒸发。当在高温下退火时，卤素从配体上裂解下来，留下固定在钙钛矿上的有机阳离子并导致电荷转移 n 型掺杂。带对齐测量表明，由强锚定配体引起的 n 掺杂钙钛矿的形成导致形成具有能量偏移的理想异质结，有利于电子提取和空穴阻挡，