Fabrication and characterization of formamidinium-based perovskite photovoltaic devices hybridized with decaphenylcyclopentasilane hole transport layers

Double-stacked formamidinium-based perovskite photovoltaic devices with different bandgaps were fabricated using decaphenylcyclopentasilane (DPPS) as the hole-transport layer, and their photovoltaic properties were evaluated. Perovskite/DPPS hybridized thin films were fabricated under a high temperature of 190 °C. The DPPS layer functioned as a protective layer and the efficiencies of the DPPS-based devices were maintained even after one year. Optical and microstructural analyses were performed to investigate the microstructure and properties of the DPPS, and its crystallization was observed after annealing. The crystal growth of the perovskite layer was enhanced in the thicker region of the crystallized DPPS film, which suggests that the suppression of CH₃NH₃ desorption by DPPS improved the quality of the perovskite films.