Multi-functionalized polysilsesquioxanes assisted synthesis of methylammonium tin bromide perovskite: A novel approach

[Display omitted] •A new hole-transporting oligomer mediated synthesis of CH3NH3SnBr3 perovskites•The oligomer can act as both a protective layer as well as a hole transport layer.•The oligomer demonstrates stability and excellent transparency in the UV–Visible NIR region. Polymeric encapsulants are proven to be defect-passivating agents which render robust perovskite films. Here, we report the new approach of synthesis of tin halide perovskite encapsulated by a transparent conducting oligomer, namely polysilsesquioxane (PSQ). The stability of the tin halide perovskite was improved using the modifier. PSQ possesses good electrical conductivity and HOMO-LUMO energy levels being suited for promoting the hole conductivity of the perovskite materials. The crystal structure, morphology, optical properties, and current-voltage characteristics of PSQ encapsulated perovskites were studied using microscopic, spectroscopic and photovoltaic characterization techniques. Photovoltaic cells were fabricated under ambient atmosphere (RH >60%) and photovoltaic conversion efficiencies (PCEs) of ~2.2% were obtained with a short-circuit current density (JSC) of ~5.4 mA/cm2, open circuit potential (VOC) of ~1.0 V and a fill factor (FF) of ~40% under 1 sun (100 mW/cm2) illumination. Our work opens a new class of chemical modifiers for improving environmental stability and can be further tuned for the development of more efficient photovoltaic conversion devices.