Solution-processed Bii3 solar cells

We present a proof-of-concept solid state solar cell with an efficiency of 1.0 % using solution-processed BÍI3 absorber layer. Spin-coated BiI3 thin films show stability in air for over one month. The films were integrated into an all-inorganic photovoltaic device with a transition-metal oxide hole transport layer. Thermal annealing BiL· films at 100 °C in a solvent vapor led to the highest short circuit current value of 6.9 ± 0.5 mA/cm
²
. In general, these devices have a large open circuit voltage deficit. EQE measurements show low collection efficiency at the BiI
₃
-TiO
₂
interface, indicating a potential pathway toward improved power conversion efficiencies.