Application of non-metal doped titania for inverted polymer solar cells

Inverted bulk-heterojunction polymer solar cells have been fabricated applying non-metal doped TiO₂ as electron extraction buffer layers. Spin-coated films from nitrogen, sulphur, and iodine doped TiO₂ nanoparticles dispersed in dimethyl sulphoxide showed comparable roughness and uniformity as those from the pure TiO₂ nanoparticles. The highest power conversion efficiency (PCE) of 1.67% was obtained for N-doped TiO₂, whereas in the case of pure TiO₂, PCE was around 1%. The highest short circuit current density (J_sc = 10.66 mA cm⁻²) was achieved for I-doped TiO₂. Moreover, it was observed that devices with doped TiO₂ exhibit better stability under constant illumination comparing to the control devices with pure TiO₂.