Development of printed perovskite solar cells based on NbInTiO₂ electron transport layers

This study brings forward fabricating printed perovskite solar cells (PSCs) utilizing a developed NbInTiO₂ electron transport layer (ETL), which incorporates both higher valence dopants (i.e., Nb⁵⁺) and lower valence dopants (i.e., In³⁺) within a titania structure. Characterization of the printed photoanode surface revealed a continuous, dense, and pinhole-free layer. X-ray diffraction analysis and X-ray photoelectron spectroscopy confirmed the presence of the anatase phase in the ETL, with an average crystallite size of 7.9 nm, and no formation of intermetallic compositions. The systematic shifts in the binding energies of both Ti and O suggested enhanced electronic properties potentially advantageous for applications in photovoltaic devices. The fabricated PSC, utilizing a film with Nb and In doping concentrations of 0.15% and 0.03%, respectively, achieved a peak power conversion efficiency of 14.3%, significantly outperforming the reference cell, which exhibited an efficiency of 7.5%. This enhancement is attributed to the lower ETL’s band gap (2.55 eV), reduced series resistance (9.0 Ω), and lower charge recombination resistance (1058.2 Ω) of the champion cell, as demonstrated through UV–Vis and electrochemical impedance spectroscopy analyses.