Enhanced performance of hole-conductor free carbon-based perovskite solar cells through polyvinylidene fluoride as additive

Abstract

Here, different amounts of polyvinylidene fluoride (PVDF) polymer composite perovskite films are prepared by a one-step spin coating process and used for mono and double mesoscopic HTM-free carbon-based perovskite solar cells (C-PSCs). The polymer incorporated perovskite film forms as larger crystals with rod-shaped grains compared to MAPbI3 film. The larger crystal grains with high crystallinity enhance charge carriers and suppress the non-radiative recombination rate. The strong interaction between PVDF and methylammonium (MA) cation via hydrogen bonding would avoid moisture penetration. Also, it suggests that the polymer bonds strongly to the perovskite surface and grain boundaries. The PVDF (1 mg mL−1 and 5 mg mL−1) added perovskite film shows a maximum power conversion efficiency of 12.4% and 10.9% with double layer and monolayer mesoscopic HTM free C-PSCs, respectively. The double and mono mesoscopic C-PSCs devices retained 80% and 90% of their initial efficiency in ambient conditions over 50 days without encapsulation. Moreover, we have investigated the durability of MAPbI3 and MAPbI3:PVDF films in thermal ambient conditions analyzed through XRD. The MAPbI3:PVDF perovskite film shows more stability than the MAPbI3 film. This work may lead to the commercialization of C-PSCs by reducing costs and improving performance and stability.