Room-temperature carbon electrodes with ethanol solvent interlacing process for efficient and stable planar hybrid perovskite solar cells

Abstract

Among the next-generation photovoltaic technologies, perovskite solar cells (PSCs) have attracted significant attention and interest. However, PSCs typically use high-vacuum processed metal electrodes, which are considerably more expensive. Furthermore, this process using noble metals, results in dramatic performance degradation after halide ion migration and thermal stress. Therefore, replacing metal electrodes with carbon electrodes is a promising way to address the stability issues of PSCs. This is due to carbon materials possessing unique qualities, such as low cost, high stability, good conductivity, and inherent water resistance. In contrast, some solvents in commercial carbon paste cause damage to the structure of perovskite films. Herein, room-temperature carbon films were successfully prepared utilizing an ethanol solvent interlacing process with time optimization. The resulting carbon films exhibited good flexibility inducing tight adhesion onto the hole transporting layer as well as excellent electrical properties. The carbon films were then applied as working electrodes in PSCs structured as FTO/TiO2/Cs0.17FA0.83Pb(I0.83Br0.17)3/spiro-OMeTAD/carbon. By optimizing time, in the ethanol solvent interlacing process, an excellent power conversion efficiency (PCE) was achieved. The devices improved up to 12.2% using the soaked carbon films at 2 h. Moreover, the device exhibits excellent long-term stability of 80% over 1000 h in air environment without encapsulation. Finally, this simple and effective technique proposes an alternate choice for developing efficient carbon-based PSCs.