Modeling Advanced Halide Perovskite Materials for Solar Energy Harvesting and Optoelectronics

Thin film morphology is a key factor determining the performance of bulk heterojunction organic solar cells through its influence on charge separation, transport and recombination losses in donor-acceptor blends. With this respect, both descriptive and predictive modeling of structural properties of blends of PCBM or hybrid perovskites of the type CH₃NH₃PbX₃ (X=Cl, Br, I) with P3HT, P3BT and SQ2 dye sensitizer, including adsorption on TiO₂ clusters having rutile (110) surface, is presented with the use of a methodology that allows computing the microscopic structure of blends on the nanometer scale and getting insight on miscibility of its components at various thermodynamic conditions. The methodology is based on the integral equation theory of molecular liquids and the density functional theory. A remarkably good agreement with available experimental data and results of alternative modeling is observed for PCBM in P3HT system. We interpret this as a validation of our approach for organic photovoltaics and support of its results for new systems that do not have reference data for comparison or calibration. The calculated nanoscale morphologies of blends of P3HT, P3BT or SQ2 with perovskites and TiO₂ are all new and guide the rational design of organic/hybrid photovoltaics.