High quality W doped SnO₂ electron transporting layer is prepared using molecular precursor containing SnC₂O₄ and (NH₄)₁₀W₁₂O₄₁ ⋅ xH₂O, which could effectively modify the electric conductivity and energy band position of resulting SnO₂ film. Therefore, power conversion efficiency of the perovskite solar cells with W doped SnO₂ layer are impressively promoted.

Abstract

For low temperature (≤180 °C) processed perovskite solar cells (PSCs), SnO₂ has been proven to be one of the most effective electron transporting layer. However, problems, such as poor electric conductivity and high defect density, inevitably exist in the SnO₂ films which are fabricated using low temperature solution methods. Element doping of SnO₂ film is a feasible strategy to alleviate the above problems. Herein, W doping of the SnO₂ is realized through addition of ammonium tungstate hydrate into the molecular precursor of SnO₂. The W doped SnO₂ film exhibits higher conductivity, and can better extract and transport the electrons from the perovskite films. Hence, power conversion efficiency is boosted from 20.60 % for the reference PSCs to 21.83 % for PSCs fabricated on 2.5 mg mL⁻¹ ammonium tungstate hydrate doped SnO₂ films.