Integrating Low-Stack Photonic Crystals with the Honeycomb-like Structural Framework to Enhance the Photovoltaic...

An inverse opal structure of SnO₂ with a honeycomb morphology is introduced as the framework for the attached perovskite materials and functional layers in the hybrid perovskite-based solar cells simultaneously. Three different pore sizes of polystyrene microsphere layers, with diameters of 350, 480, and 600 nm, were fabricated through a vertical self-assembly vaporization technique. The polystyrene (PS) layer served as the sacrificial template for the inverse opal structure. By controlling the spinning parameters, the inverse opal-structured SnO₂ layer was used to constrain them into a single-layer stacking structure. These layers with varying pore sizes were subsequently applied onto a dense electron transport layer that is in contact with the perovskite layer. A carbon electrode is used as photovoltaic solar cells. The major benefits of this approach were systematically analyzed through structural characterizations and various means. The semiphotonic crystal layer induces modulation effects, resulting in increased light absorption and surface area, which leads to a substantial increase in short-circuit density. By studying the electrochemical properties in the dark to exclude the influence of optical effects, we attribute the slight increase in the fill factor to the increased surface area, which enhances carrier transport. Among the different layers, the inverse opal layer prepared with 480 nm polystyrene microspheres displayed superior photovoltaic performance parameters due to its appropriate surface area and relatively higher light absorption. The power conversion efficiency of the MAPbI₃ perovskite solar cell showed a relative enhancement of 55%. Additionally, aging tests demonstrated that devices with the additional structural layer exhibited good endurance under conventional atmospheric conditions after 1440 h of aging.