Modeling of germanium-based Perovskite Solar Cell for different hole transport materials and defect density

Abstract

The performance of four distinct materials (organic and inorganic) was simulated and analyzed as hole transport layer (HTL) in the design of germanium (Ge)-based Perovskite Solar Cell (PSC). A 1-dimensional numerical software (SCAPS 1-D) has been applied to simulate the HTL candidates: spiro-OMeTAD, PTAA, nickel oxide (NiO), and copper (I) thiocyanate (CuSCN), with tin (IV) dioxide (SnO2) as the electron transport layer (ETL). The thickness of the methylammonium germanium iodide (CH3NH3GeI3) absorber varied from 300 nm to 1100 nm, and the highest simulated power conversion efficiency was achieved at 800 nm for all HTL candidates. It was observed that the inorganic CuSCN outperformed its counterparts with a power conversion efficiency (PCE) of 25.38%. The effect of the perovskite absorber’s defect density was investigated, and ultimately, it was demonstrated that this value is disproportionately related to the PCE. A reduction of nearly 98% in PCE was recorded when the defect density increased from 1×1014 cm-3 to 1×1020 cm-3. Additionally, for a constant ETL thickness of 80 nm, it was revealed that the PCE would decrease slightly, ranging from 0.1% to 0.3%, with an increase in HTL thickness from 50 nm to 300 nm. Comparing the PCE of our current work with published reports further justifies its competitiveness.