Currently, the most efficient perovskite solar cells (PSCs) mainly use planar and mesoporous titanium dioxide (TiO₂) as an electron-transport layer (ETL). However, because of its intrinsic photocatalytic properties, TiO₂ can decompose perovskite absorber and lead to poor stability under solar illumination (ultraviolet light). Herein, a simplified architectural ETL-free PSC with enhanced efficiency and outstanding photostability is produced by the facile deposition of a bathocuproine (BCP) interlayer. Power conversion efficiency of the ETL-free PSC improves from 15.56 to 19.07% after inserting the BCP layer, which is the highest efficiency reported for PSCs involving an ETL-free architecture, versus 19.03% for the n–i–p full device using TiO₂ as an ETL. The BCP interlayer has been demonstrated to have several positive effects on the photovoltaic performances of devices, such as “modulation doping” of the perovskite layer, modification of FTO surface work function, and enhancing the charge-transfer efficiency between FTO and perovskite. Moreover, the BCP-based ETL-free devices exhibit outstanding photostability: the unencapsulated BCP-based ETL-free PSCs retain over 90% of their initial efficiencies after 1000 h of storage in air and maintain 92.2% after 450 h of exposure to full solar irradiation (without a UV filter), compared to only 14.1% in the n–i–p full cells under the same condition.

中文翻译：

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高效且光稳定的无电子传输层的钙钛矿太阳能电池的绝缘中间层

当前，最有效的钙钛矿太阳能电池（PSC）主要使用平面和中孔的二氧化钛（TiO ₂）作为电子传输层（ETL）。然而，由于其固有的光催化性能，TiO ₂可以分解钙钛矿吸收剂并导致在太阳光（紫外线）下的稳定性差。在此，通过浴淀积素（BCP）中间层的简便沉积，可以生产出具有增强的效率和出色的光稳定性的，简化的无ETL的PSC体系结构。插入BCP层后，无ETL的PSC的功率转换效率从15.56％提高到19.07％，这是涉及无ETL架构的PSC的最高效率，而使用TiO的n–i–p完整器件的功率转换效率为19.03％_2个作为ETL。已证明BCP中间层对器件的光伏性能具有若干积极影响，例如钙钛矿层的“调制掺杂”，FTO表面功函数的改性以及增强FTO与钙钛矿之间的电荷转移效率。此外，基于BCP的无ETL的设备还具有出色的光稳定性：未封装的基于BCP的无ETL的PSC在空气中存储1000小时后仍保持其初始效率的90％以上，并在暴露于完全太阳能下450 h后保持92.2％的初始效率。照射（不使用紫外线过滤器），相比之下，在相同条件下n–i–p个全细胞中只有14.1％。