Interface Recombination in Depleted Heterojunction Photovoltaics based on Colloidal Quantum Dots

Interface recombination was studied in colloidal quantum dot photovoltaics. Optimization of the TiO2-PbS interface culminated in the introduction of a thin ZnO buffer layer deposited with atomic layer deposition. Transient photovoltage measurements indicated a nearly two-fold decrease in the recombination rate around 1 sun operating conditions. Improvement to the recombination rate led to a device architecture with superior open circuit voltage (V-OC) and photocurrent extraction. Overall a 10% improvement in device efficiency was achieved with Voc enhancements up to 50 mV being realized.