Efficient light harvesting in perovskite layer via three-dimensional TiO2 nanobranched nanorod scaffold

A comparative study was done on three types of TiO2 thin film morphology, i.e., mesoporous nanoparticles, nanorods, and nanobranched nanorods thin films, as the scaffold for the perovskite solar cell. The performances of the perovskite-coated thin films were compared in terms of charge carrier extraction, charge transport, and solar energy harvesting via photoluminescence and UV-vis spectroscopies. TiO2 nanobranched nanorods thin film showed better photovoltaic performance than those of mesoporous nanoparticles and nanorods thin films. The better optical properties of nanobranched nanorods thin film as the scaffold is ascribed to its unique morphological advantages, i.e., remarkable specific surface area along with high-speed pathways for charge carriers. These characteristics lead to great, compact, and uniform perovskite loading, excellent electron transport property, and desired light harvesting performance, which are preferable features for promoting the efficiency of the perovskite solar cells. This paper introduces an outstanding scaffold for fabrication of high-performance perovskite solar cells.