IMPROVING EFFICIENCY OF PEROVSKITE SOLAR CELLS WITH 18C6DOPED SNO2 ELECTRON TRANSPORT LAYER
Abstract - Perovskite solar cells (PSCs), with their low cost and high conversion efficiency, have emerged as the most promising solar cell technology in recent years. In the structure of PSCs, the electron transport layer (ETL) plays a crucial role in providing an intrinsic electric field and assisting carrier transport. The traditional TiO2 ETL material has issues requiring high-temperature sintering and is prone to perovskite degradation under illumination. Therefore, many researchers have begun to develop SnO2 ETL that have advantages of low-temperature processes and stability under illumination.
However, the SnO2 ETL has problems with carrier transport and mismatch with the perovskite interface lattice, which easily leads to carrier transport and recombination in the ETL, thereby reducing the conversion efficiency of PSCs. To improve this issue, in this study, we added different proportions of 18-crown-6 (18C6) to the SnO2 precursor solution and observed its effect on the SnO2 thin film. Through the analysis and observation of Scanning Electron Microscopy (SEM) and Conductive Atomic Force Microscopy (C-AFM), we found that adding 18C6 molecules can improve the surface roughness of the SnO2 ETL and effectively enhance charge conduction in the electron transport layer, while also increasing the hydrophilicity of the SnO2 ETL and assisting in the growth of subsequent perovskite thin film grains. The results of steady-state photoluminescence (PL) and time-resolved photoluminescence (TR-PL)analysis showed that adding 18C6 to SnO2 can help improve charge transport at the PVSK/ETL interface, thereby increasing the conversion efficiency of perovskite solar cells from the original 16.61 % to 19.10 % (Voc = 1.07 V, Jsc = 22.75 mA/cm2, F.F. = 78 %), an efficiency increase of 15 %.
Keywords - Perovskite、Solar cell、SnO2 ETL