Mechanism and regulation of tensile-induced degradation of flexible perovskite solar cells

Flexible perovskite solar cells (FPSCs) are promising next-generation photovoltaic devices, but the poor mechanical stability issue is still a huge obstacle to their commercialization. In this work, we investigate the mechanism of tensile-induced degradation of FPSCs through experiment and theoretical analysis. We demonstrate that the cracks of the indium tin oxide electrode layer (ITO) and perovskite (PVK) layer induced by tensile stress play a major role in the efficiency degradation of FPSCs. To relieve the internal stress concentration, a polyelectrolyte layer (D-PAA/C-EA modified SnO2) is proposed for strain engineering, which is confirmed by both numerical simulation and experiment. The threshold strain of device failure for D-PAA/C-EA modified FPSCs is nearly twice that of the original FPSCs, signifying its potential in enhancing the mechanical stability of the devices. Cracks induced by tensile stress in functional layers cause performance degradation in flexible perovskite solar cells (FPSC). FPSCs with a D-PAA/C-EA modified SnO2 layer exhibit nearly double the device failure strain compared to the original FPSCs.