A robust buried interface in perovskite solar cells by pre-burying co-component molecule of perovskite

Abstract

Interfaces are crucial factors in perovskite solar cells (PSCs), determining carrier separation, transport, collection, and recombination. The buried interface shows serious defects that are challenging to address directly, thus attracting researchers' attention. This study reveals that the buried interface not only impacts device performance due to defects but also affects the adhesion strength of perovskite on the substrate, which is detrimental to the stable operation of PSCs. To address the dual challenges caused by the buried interface, the strategy of pre-burying co-component molecules has been proposed. By peeling off the perovskite film samples based on the pre-burying strategy, it is found that the interface adhesion strength is significantly enhanced, even surpassing the strength of the perovskite bulk phase. Furthermore, the passivation of interface defects and optimization of energy level alignment are achieved, attributed to the change of the interface state, resulting in an effective reduction in non-radiative recombination losses and an obvious enhancement in the extraction and transport of interface charge carriers. Based on this strategy, the device performance achieved a significant improvement. Unpackaged devices maintained over 90 % of their initial efficiency after being stored for 2000 h at 20 % RH. The pre-buried co-component molecular strategy provides a novel approach for constructing robust buried interfaces, offering potential guidance for the advancement of interface engineering in high-performance PSCs.