Ultra-thin platinum interfacial layer assisted-photovoltaic response of transparent Pb(Zr,Ti)O3 thin film capacitors

For transparent solar cells, Sn:In2O3/Pb(Zr, Ti)TiO3/Pt(⩽5 nm)/Sn:In2O3 capacitor structures were fabricated using a cost-effective solution process. The insertion of ultra-thin Pt layer between the bottom Sn:In2O3 electrode and Pb(Zr, Ti)TiO3 plays a critical role in the photovoltaic characteristics of the capacitors. The Pb(Zr,Ti)O3 capacitors with a 5 nm thick Pt layer showed excellent polarization-voltage curves with reduced leakage current due to both partial (1 1 1) orientation of Pb(Zr,Ti)O3 and alloy formation between Pt and the Sn:In2O3 bottom electrode, as confirmed using X-ray photoelectron spectra analysis. The capacitors with a 5 nm thick Pt layer exhibit transmittance of 45-50% in the visible light region. The current density-voltage characteristics under light illumination (AM1.5G) exhibit an open circuit voltage value of −0.62 V and short circuit current density of 0.6 μA/cm2 after negative poling, with a maximum power conversion efficiency of 1.7 × 10−4%. The open circuit voltage of the capacitors with a 5 nm thick Pt layer is larger with negative poling due to the higher net internal bias arising from the Schottky barrier.