Since the advent of formamidinium (FA)-based perovskite photovoltaics (PVs), significant performance enhancements have been achieved. However, a critical challenge persists: the propensity for void formation in the perovskite film at the buried perovskite–interlayer interface has a deleterious effect on device performance. With most emerging perovskite PVs adopting the p-i-n architecture, the specific challenge lies at the perovskite–hole transport layer (HTL) interface, with previous strategies to overcome this limitation being limited to specific perovskite–HTL combinations; thus, the lack of universal approaches represents a bottleneck. Here, we present a novel strategy that overcomes the formation of such voids (microstructural defects) through a film treatment with methylammonium chloride (MACl). Specifically, our work introduces MACl via a sequential deposition method, having a profound impact on the microstructural defect density at the critical buried interface. Our technique is independent of both the HTL and the perovskite film thickness, highlighting the universal nature of this approach. By employing device photoluminescence measurements and conductive atomic force microscopy, we reveal that when present, such voids impede charge extraction, thereby diminishing device short-circuit current. Through comprehensive steady-state and transient photoluminescence spectroscopy analysis, we demonstrate that by implementing our MACl treatment to remedy these voids, devices with reduced defect states, suppressed nonradiative recombination, and extended carrier lifetimes of up to 2.3 μs can be prepared. Furthermore, our novel treatment reduces the stringent constraints around antisolvent choice and dripping time, significantly extending the processing window for the perovskite absorber layer and offering significantly greater flexibility for device fabrication.

中文翻译：

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克服甲脒基钙钛矿太阳能电池埋入界面的微观结构缺陷


自从基于甲脒 (FA) 的钙钛矿光伏 (PV) 出现以来，性能得到了显着增强。然而，一个关键的挑战仍然存在：埋入钙钛矿-夹层界面处的钙钛矿薄膜中形成空隙的倾向对器件性能产生有害影响。随着大多数新兴钙钛矿PV采用pin架构，具体的挑战在于钙钛矿-空穴传输层（HTL）界面，之前克服这一限制的策略仅限于特定的钙钛矿-HTL组合；因此，缺乏通用方法是一个瓶颈。在这里，我们提出了一种新策略，通过使用甲基氯化铵 (MACl) 进行薄膜处理来克服此类空隙（微观结构缺陷）的形成。具体来说，我们的工作通过顺序沉积方法引入了 MACl，对关键埋入界面处的微观结构缺陷密度产生了深远的影响。我们的技术与 HTL 和钙钛矿薄膜厚度无关，突出了这种方法的通用性。通过采用器件光致发光测量和传导原子力显微镜，我们发现，当存在时，此类空隙会阻碍电荷提取，从而减少器件短路电流。通过全面的稳态和瞬态光致发光光谱分析，我们证明，通过实施 MACl 处理来弥补这些空隙，可以制备出缺陷态减少、非辐射复合受到抑制以及载流子寿命延长至 2.3 μs 的器件。 此外，我们的新颖处理方法减少了围绕反溶剂选择和滴注时间的严格限制，显着延长了钙钛矿吸收层的加工窗口，并为器件制造提供了更大的灵活性。