Fabrication and characterization of a solution-processed electron transport layer for organic-inorganic hybrid halide perovskite photovoltaics

Highlights: •Zinc oxide nanoparticles were used as the electron transport layer. •Perovskite film was prepared by a liquid two-step method. •The optimal annealing temperature and duration were 80 °C and 10 min. •The optimal volume ratio of isopropyl alcohol to toluene was 9:1. •Energy conversion efficiency of 15.78% were obtained. -- Abstract: In this study, suspended zinc oxide nanoparticles were used as the electron transport layer in trans-perovskite solar cells. The perovskite film was prepared by a liquid two-step method, and the crystallinity, surface morphology, and optical and photoelectric properties of the perovskite films were then investigated. The results showed that the crystallinity and film compactness of the perovskite could be controlled by the stoichiometric quantity and the perovskite formation rate. Moreover, the film morphology was affected by the annealing temperature, duration, and the amount of toluene solvent, which could be leveraged to enhance the efficiency of the device due to the charge trapping defect. The optimal annealing temperature and duration were 80 °C and 10 min, and the optimal volume ratio of isopropyl alcohol to toluene was 9:1. The highest performing perovskite solar cells in this study exhibited an energy conversion efficiency of 15.78%, a short-circuit current of 20.80 mA/cm², an open circuit voltage of 1.10 V, and a fill factor of 0.69.