Bulk heterojunction polymer solar cell and perovskite solar cell: Concepts, materials, current status, and opto-electronic properties

Recently, the demand for sustainable and clean energy resources has led to an intense growth in the development of different types of solar cells. Among all types of photovoltaics, polymer solar cells and perovskite solar cells have received extensive attention because of their potential for achieving cheap, light weight, facile and fast fabricated devices. Bulk heterojunction polymer solar cells have been considered for about two decades, while perovskite ones have introduced just for 7 years. Comparison of these devices indicates a higher performance for perovskite solar cells. This review starts by comparative introducing of configurations, materials, mechanisms, fabrication methods, crystalline natures, band gap tuning, and the current status of the photovoltaic performances of polymer and perovskite solar cells. We emphasize the importance of the optoelectronic properties of the absorber layers including absorption coefficient, exciton binding energy, exciton dissociation, exciton and charge carrier lifetimes, charge carrier mobility, and exciton and charge diffusion lengths. Suggestions regarding needed improvements and future research directions in the field of polymer and perovskite solar cells are provided.