Exploring the performance of perovskite solar cells with dual hole transport layers via SCAPS-1D simulation

The potential of perovskite solar cells (PSCs) to produce high efficiency (over 25 %) is well known, but the poor stability of these solar cells is still a concern for practical applications. Thus, improving the stability is essential for furthering the development of PSCs. To address this issue, researchers found that incorporating inorganic materials into the hole transport layers (HTLs) can improve the stability of PSCs, yet charge recombination at the interface between the perovskite and inorganic HTLs can still reduce the efficiency of the PSCs. This study simulated the performance and mechanism of methyl ammonium lead iodide (MAPbI3) PSCs with a dual HTL using Solar Cell Capacitance Simulator-one Dimension (SCAPS-1D). A dual HTL formed by combining Spiro-OMeTAD (spiro), a highly efficient hole transport material, and copper zinc tin sulfide (CZTS), a highly stable hole transport material, leads to a PSC with a power conversion efficiency (PCE) of 23.47 % and significantly improved stability. Simulation results of the electric field at the interfaces of PSCs indicated that the PSC with spiro/CZTS as dual HTL have enhanced charge separation and reduced recombination. Furthermore, the simulation results have also revealed the influence of different parameters, such as absorber thickness, absorber defect density, HTL thickness, HTL/absorber interface defects, temperature, series resistance, and shunt resistance, on solar cell’s characteristics.