Polycrystalline Thin-Film TiO2/Se Solar Cells

A new type of selenium solar cell with a titanium dioxide (TiO₂)/Se heterojunction has been fabricated by low-cost process. An efficiency of 5.01% under AM 1.5 illumination (100 mW/cm²) has been achieved without antireflection coatings. The corresponding short-circuit current density, open-circuit voltage, and fill factor are 10.8 mA/cm², 0.884 V, and 0.525, respectively. The efficiency is the highest among Se-based solar cells reported to date. These cells also have extremely high spectral response at short wavelengths, resulting in efficiencies of 11-13% under fluorescent light (500 lux).