Conventional titanium oxide (TiO₂) as an electron transport layer (ETL) in hybrid organic-inorganic perovskite solar cells (PSCs) requires a sintering process at a high temperature to crystalize, which is not suitable for flexible PSCs and tandem solar cells with their low-temperature-processed bottom cell. Here, we introduce a low-temperature solution method to deposit a TiO₂/tin oxide (SnO₂) bilayer towards an efficient ETL. From the systematic measurements of optical and electronic properties, we demonstrate that the TiO₂/SnO₂ ETL has an enhanced charge extraction ability and a suppressed carrier recombination at the ETL/perovskite interface, both of which are beneficial to photo-generated carrier separation and transport. As a result, PSCs with TiO₂/SnO₂ bilayer ETLs present higher photovoltaic performance of the baseline cells compared with their TiO₂ and SnO₂ single-layer ETL counterparts. The champion PSC has a power conversion efficiency (PCE) of 19.11% with an open-circuit voltage (V_oc) of 1.15 V, a short-circuit current density (J_sc) of 22.77 mA cm⁻², and a fill factor (FF) of 72.38%. Additionally, due to the suitable band alignment of the TiO₂/SnO₂ ETL in the device, a high V_oc of 1.18 V is achieved. It has been proven that the TiO₂/SnO₂ bilayer is a promising alternative ETL for high efficiency PSCs.

混合有机-无机钙钛矿太阳能电池（PSC）中作为电子传输层（ETL）的常规二氧化钛（TiO ₂）需要高温下的烧结过程才能结晶，这不适用于柔性PSC和串联式太阳能电池。低温处理的底部电池。在这里，我们介绍了一种低温溶液法，以向高效ETL沉积TiO ₂ /氧化锡（SnO ₂）双层。通过光学和电子性质的系统测量，我们证明了TiO ₂ / SnO ₂ETL具有增强的电荷提取能力，并且在ETL /钙钛矿界面处的载流子重组受到抑制，这两者都有利于光生载流子的分离和运输。结果，与它们的TiO ₂和SnO ₂单层ETL对应物相比，具有TiO ₂ / SnO ₂双层ETL的PSC表现出更高的基线电池光伏性能。冠军PSC的功率转换效率（PCE）为19.11％，开路电压（V _oc）为1.15 V，短路电流密度（J _sc）为22.77 mA cm ^-2，填充系数为（ FF）为72.38％。此外，由于TiO具有合适的能带取向_{设备中的2} / SnO ₂ ETL可以实现1.18 V的高V _oc。已经证明，TiO ₂ / SnO ₂双层是高效PSC的有希望的替代ETL。