Understanding the role of interconnecting layer on determining monolithic perovskite/organic tandem device carrier recombination properties

As one of the core parts of two-terminal (2T) monolithic tandem photovoltaics, the interconnecting layers (ICLs) play a critical role in modulating the carrier transport and recombination between the sub-cells, and thus influencing the tandem device performance. Here, for the first time, the relationship between ICLs architecture and 2T monolithic perovskite/organic tandem device performance has been studied by investigating the change of ICLs composition layer thickness on the ICLs optical and electrical properties, sub-cells EQE properties, and tandem device J-V properties. It is revealed that the ability of ICLs on modulating the sub-cells carrier balance properties is strongly associated with its composited layers thickness, and the tandem device carrier balance properties can be reflected by the relative EQE intensity between the sub-cells. Finally, with a deep understanding of the mechanisms, rational design of ICLs can be made to benefit the tandem device development. Based on the optimized ICL a high PCE of 20.03% is achieved.