Abstract：
The bottom contact in perovskite solar cells (PSCs) is easy to cause deep trap states and severe instability issues, especially under maximum power point tracking (MPPT). In this study, sodium gluconate (SG) is employed to disperse tin oxide (SnO2) nanoparticles (NPs) and regulate the interface contact at the buried interface. The SG-SnO2 electron transfer layer (ETL) enabled the deposition of pinhole-free perovskite films in ambient air and improved interface contact by bridging effect. SG-SnO2 PSCs achieved an impressive power conversion efficiency (PCE) of 25.34% (certified as 25.17%) with a high open-circuit voltage (VOC) exceeding 1.19 V. The VOC loss is less than 0.34 V relative to the 1.53 eV bandgap, and the fill factor (FF) loss is only 2.02% due to the improved contact. The SG-SnO2 PSCs retained around 90% of their initial PCEs after 1000 h operation (T90 = 1000 h), higher than T80 = 1000 h for the control SnO2 PSC. Microstructure analysis revealed that light-induced degradation primarily occurred at the buried holes and grain boundaries and highlighted the importance of bottom-contact engineering.
摘要：
钙钛矿太阳能电池（PSC）的底部接触容易引起深陷阱状态和严重的不稳定问题，特别是在最大功率点跟踪（MPPT）。在这项研究中,葡萄糖酸钠（SG）用于分散氧化锡（SnO2）纳米颗粒（NP）并调节掩埋界面处的界面接触。SG-SnO2电子传输层（ETL）可以在环境空气中沉积无针孔的钙钛矿薄膜，并通过桥接效应改善了界面接触。SG-SnO2PSC实现了令人印象深刻的25.34％的功率转换效率（PCE）（认证为25.17％），高开路电压（VOC）超过1.19V。相对于1.53eV带隙，VOC损耗小于0.34V，并且由于改进的接触,填充因子(FF)损失仅为2.02%。SG-SnO2PSC在1000小时手术后保留了约90%的初始PCE(T90=1000小时)，对于对照SnO2PSC，高于T80=1000小时。微观结构分析表明，光致降解主要发生在埋孔和晶界，并强调了底部接触工程的重要性。
