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In situ fabrication of an ordered macroporous perovskite semitransparent film on a FTO glass was successfully achieved via sacrificial polystyrene (PS) microsphere templates. The average visible transmittance of active layer from 20% to 45% can be tuned by simply changing the PS diameters and precursor concentrations. The ordered macroporous perovskite films show enhanced crystallinity and reduced recombination defects, superior to the island perovskite film. Transient photovoltage, transient photocurrent and electrochemical impedance spectra measurements proved the advanced charge transport and reduced recombination by importing macroporous structures. Herein, the optimized 400 nm MP CH3NH3PbI3 perovskite film with a high AL AVT of 36.5% achieved an impressive PCE of 11.7% compared to the island-like perovskite film (champion PCE = 5.6%), presenting a great potential for building integrated photovoltaic applications. [ABSTRACT FROM AUTHOR]

The power conversion efficiency (PCE) of a planar perovskite solar cell (PSC) is closely associated with the conduction band energy, conductivity and coverage of the compact layer. However, as the most widely used compact layer material, TiO2 has unfavorable electrical properties such as low electron mobility and conductivity; as a result, modifications such as elemental doping are of paramount importance. In this study, Nb-doped TiO2 with improved carrier density and conductivity was prepared via a facile one-pot solution process and applied successfully as a high-quality compact layer for planar PSCs. A positive shift in the flat-band potential (Vfb) and increased conductivity after Nb doping efficiently facilitated photogenerated electron injection and charge extraction from the perovskite film to the 2% Nb-doped TiO2 compact layer, contributing to impressive advances in photovoltaic performance compared with pristine TiO2. Ultimately, a PSC assembled using optimized 2% Nb-doped TiO2 and CH3NH3PbI3 yielded a power conversion efficiency of up to 16.3%. [ABSTRACT FROM AUTHOR]