Abstract Perovskite solar cells (PSC) are familiar with solar energy applications, which provide high power conversion efficiency quickly, are cost-effective, lightweight, and have high absorption behaviour. However, poor interfacial charge buildup between the perovskite and the electron transport layer influences limited electron mobility, reduced absorption coefficient, and variations in band gap, all of which limit the overall efficiency of the system. This research aims to mitigate the above challenges and enhance the functional performance of PSCs configured with a 40 nm tin oxide (SnO 2 ) electron transport layer, where the interface quality is modified with a polyethylenimine (PEI) modifier at layer thicknesses of 3 nm, 6 nm, and 9 nm. The PSC layer is configured with PEI and SnO 2 via spin coating technology. The fabricated model contains an Indium Tin Oxide (ITO) base window layer, Formamidinium-Methylammonium Lead Mixed Halide perovskite absorption layer, SnO 2 ETL with PEI modifier, PCBM interface layer, Spiro-OMeTAD hole transport layer (HTL) and copper back contact layer. The effect of PEI on the functional performance of PSC, in combination with SnO 2 , is experimentally investigated, and its structure is analyzed using the X-ray diffraction method, which reveals the significant contribution of PEI and SnO 2 in PSC, as indicated by distinct peaks with better crystalline size. However, the 9 nm SnO 2 ETL embedded PSC has been found to have optimum functional properties, such as a higher power conversion efficiency (PCE) of 21.6 %, a better short-circuit current density (Jsc) of 25.6 mA/cm 2 , a good open-circuit voltage (Voc) of 1.17 V, and an improved fill factor of 79.6 %. This optimized configuration has an absorption coefficient peaked at 1.75 × 10 4 per cm with the largest crystalline size of 25.5 nm and quantum efficiency of 86 %, indicating overall best performance.
Šul et al. (Tue,) studied this question.