Light absorption enhancement by embedding submicron scattering TiO2 nanoparticles in perovskite solar cells

Efficient light absorption is a key issue for hybrid perovskite solar cells (PSCs) to achieve better photovoltaic performances. Here, we introduce submicron scattering TiO2 (s-TiO2) nanoparticles into the mesoporous TiO2 layer to improve the overall light harvesting efficiency in PSCs. Obviously enhanced current density and power conversion efficiency (PCE) were accomplished due to the improved light trapping in the active layer. Corresponding enhancement mechanisms were studied by the absorption spectra and finite-difference time-domain (FDTD) simulation results. Electrochemical impedance spectroscopy (EIS) measurements were further carried out to investigate the charge transportation process influenced by introducing s-TiO2 into the mesostructured layer. With the optimized amount of embedded s-TiO2, an average of over 5% PCE enhancement with an efficiency up to 16.72% was achieved compared with the regular mesostructured PSCs.