SCAPS-1D numerical simulation of carbon-based perovskite solar cells with TiO2-doped Tm as potential n-type materials

The urgency to reduce the issue of high CO 2 emissions encouraged the growth of renewable energy worldwide. Solar energy is one of the promising renewable resources, which is versatile, clean, and widely available. Perovskite materials show properties like high charge mobility, tunable band gap, and easy synthesis route, thus leading to high power conversion efficiency of 25.7% when used as absorbers in solar cells. Although perovskite solar cells (PSCs) exhibit outstanding optoelectronic properties, the use of lead limits commercialization due to its toxicity, and metal electrodes (Ag, Al, Au, and Cu) cause chemical corrosion, metal-ion migration, and structural degradation. Herein, using lead-free Ruddlesden-Popper (RP) 2D perovskite (CH 3 NH 3 ) 2 CuCl 4 as the absorber and carbon as the back contact, we scrutinize the fundamentals of pure TiO 2 and TiO 2 doped with Tm at different mol% for potential application as the electron transport layer (ETL) in carbon-based perovskite solar cells. The experimental band gap of Tm was utilized in the numerical simulation of the designation of Carbon-based perovskite solar cells using the general configuration of FTO/ETL/(CH 3 NH 3 ) 2 CuCl 4 /CZTSe/C via SCAPS-1D simulator. Several factors, such as the thickness of the absorber layer, operating temperature, work function, and defect density (N t ), are varied. Through thickness optimization of the device layers, Tm-TiO 2 (1.0 mol%)-based device reaches the highest efficiency of 27.66% at 300K and N t of 1x10 15 cm -3 . The literature showed a steady reduction in the band gap of TiO 2 with Tm 3+ doping. The electrical conductivity properties showed an enhanced feature when TiO 2 was doped with Tm 3+ nanoparticles. This study reveals that doping TiO 2 with Tm 3+ can result in a suitable electron transport layer material, enabling highly efficient and stable carbon-based perovskite solar cells.