Advancing Halide Perovskite Solar Cell by Functional Interlayers

卤化物钙钛矿基太阳能电池（PSCs）标志着新兴光伏技术的关键转折点。法国和德国的ALSATIAN项目旨在通过开发新的功能性薄膜涂层来提高PSCs的可靠性，从而提高高效电池的稳定性。以效率为中心的PSCs的快速发展有可能只追求一种特定的器件异质结构，而这种异质结构实际上可能在可靠性方面不理想。ALSATIAN将超越标准的中间层材料，专注于新型薄膜材料和沉积工艺，通过在电池中钙钛矿吸收剂附近的原子层沉积（ALD）和分子层沉积（MLD）来处理中间层，作为传输层、复合层或钝化层。利用原位和操作技术，我们计划评估功能中间层和钙钛矿之间的界面对器件性能和稳定性的影响。主要目的是评估层间沉积过程和层间本身与钙钛矿膜的兼容性，因为化学反应会引发快速降解或产生阻碍设备功能的缺陷位点。然而，对于一个稳定的界面系统，功能层可以提供钙钛矿膜的保护和改善光电性能。因此，我们将采用先进的光谱工具与DFT计算相结合来研究界面层生长过程中发生的化学反应途径。此外，我们将研究在各种化学环境的操作条件下可能引起的层之间的（光）电化学反应。为此，我们将通过硬x射线光发射评估埋藏界面，并确定关键的电子性质，我们将与空间分辨光学光谱数据相关联。同时，我们将研究功能薄膜涂层和钙钛矿层之间的界面对器件性能和稳定性的影响，即在生长步骤之间，或操作，即在适应的器件架构中操作太阳能电池。

Halide perovskite based solar cells (PSCs) mark a critical turning point for emerging photovoltaic technologies. The French-German project ALSATIAN aims at enhancing the reliability of PSCs by developing new functional thin-film coatings that will improve stability of high efficiency cells. Rapid efficiency-focused progress in PSCs risks pursuing only a particular device heterostructure which may in fact be nonideal in terms of reliability. ALSATIAN will look beyond standard interlayer materials to focus on novel thin-film materials and deposition procedures to process interlayers by atomic layer deposition (ALD) and molecular layer deposition (MLD) adjacent to the perovskite absorber in the cell to serve as transport, recombination, or passivation layer. Using in situ and operando techniques, we plan to assess the impact of the interface between functional interlayer and perovskite on the device performance and stability. A major objective is to evaluate the compatibility of the interlayer deposition process and the interlayer itself with the perovskite film, since chemical reactions can initiate rapid degradation or create defect sites that impede device functionality. However, for a stabilized interface system the functional layer can provide protection of the perovskite film and improve optoelectronic properties. Hence, we will employ advanced spectroscopic tools paired with DFT calculations to investigate chemical reaction pathways that occur during layer growth at the interfaces. In addition, we will study (photo-)electrochemical reactions between the layers that could be induced under operating conditions in various chemical environments. To this end, we will assess buried interfaces by hard X-ray photoemission and determine key electronic properties, which we will correlate to data from spatially resolved optical spectroscopy. In combination, we will investigate the impact of the interface between the functional thin-film coating and perovskite layer on the device performance and stability in-situ, i.e., in between growth steps, or operando, i.e., for operating solar cells in adapted device architectures.