Song Wenya, Rakocevic Lucija, Thiruvallur Eachambadi Raghavendran, Qiu Weiming, Bastos João P, Gehlhaar Robert, Kuang Yinghuan, Hadipour Afshin, Aernouts Tom, Poortmans Jef
imec-Partner in Solliance and Energyville, Thor Park 8320, 3600 Genk, Belgium.
Department of Electrical Engineering (ESAT), Katholieke Universiteit Leuven, Kasteelpark Arenberg 10, 3001 Heverlee, Belgium.
ACS Appl Mater Interfaces. 2021 Sep 22;13(37):44294-44301. doi: 10.1021/acsami.1c11227. Epub 2021 Sep 9.
To guarantee a long lifetime of perovskite-based photovoltaics, the selected materials need to survive relatively high-temperature stress during the solar cell operation. Highly efficient n-i-p perovskite solar cells (PSCs) often degrade at high operational temperatures due to morphological instability of the hole transport material 2,2',7,7'-tetrakis (,-di--methoxyphenyl-amine)9,9'-spirobifluorene (Spiro-OMeTAD). We discovered that the detrimental large-domain spiro-OMeTAD crystallization is caused by the simultaneous presence of -butylpyridine (BP) additive and gold (Au) as a capping layer. Based on this discovery and our understanding, we demonstrated facile strategies that successfully stabilize the amorphous phase of spiro-OMeTAD film. As a result, the thermal stability of n-i-p PSCs is largely improved. After the spiro-OMeTAD films in the PSCs were stressed for 1032 h at 85 °C in the dark in nitrogen environment, reference PSCs retained only 22% of their initial average power conversion efficiency (PCE), while the best target PSCs retained 85% relative average PCE. Our work suggests facile ways to realize efficient and thermally stable spiro-OMeTAD containing n-i-p PSCs.
为确保基于钙钛矿的光伏器件具有较长的使用寿命，所选材料需要在太阳能电池运行期间经受相对较高的温度应力。高效的n-i-p钙钛矿太阳能电池（PSC）在高温运行时常常会因空穴传输材料2,2',7,7'-四（-二-甲氧基苯基-胺）-9,9'-螺二芴（Spiro-OMeTAD）的形态不稳定性而降解。我们发现，有害的大尺寸Spiro-OMeTAD结晶是由-丁基吡啶（BP）添加剂和作为覆盖层的金（Au）同时存在所导致的。基于这一发现及我们的认识，我们展示了能够成功稳定Spiro-OMeTAD薄膜非晶相的简便策略。结果，n-i-p PSC的热稳定性得到了大幅提高。在氮气环境中，将PSC中的Spiro-OMeTAD薄膜在85°C黑暗条件下应力处理1032小时后，参比PSC仅保留了其初始平均功率转换效率（PCE）的22%，而最佳目标PSC保留了85%的相对平均PCE。我们的工作提出了实现含Spiro-OMeTAD的高效且热稳定的n-i-p PSC的简便方法。
