Recent progress and prospects of integrated perovskite/organic solar cells

Solar cells generate renewable energy by converting sunlight into electricity based on the photovoltaic effects. Different types of solar cells have been developed with the employment of versatile organic, inorganic, and hybrid semiconductors as the photoactive layer among which perovskite and solar cells have evidenced enormous progress in recent years. The maximum achievable power conversion efficiencies of perovskite and organic solar cells have now surpassed 25% and 18%, respectively. Nevertheless, the relatively narrow light absorption region of perovskite and large open-circuit voltage loss of organic solar cells hinder their further improvements. Recently, an emerging type of photovoltaic device, an integrated perovskite/organic solar cell, by incorporating perovskites and near-infrared organic semiconductors, has obtained enhanced short-circuit current density while reserving the high open-circuit voltage of perovskite devices. Integrated perovskite/organic solar cells simplify the sophisticated fabrication processes of tandem solar cells by depositing organic semiconductors, which are dissolved in orthogonal solvents directly onto the perovskite layer, offering a novel route to utilize more photons. In this review, we start with the operational mechanism of this new type of solar cell and then introduce various devices through distinctions of the organic layer. We proceed to summarize critical factors that determine efficiency and provide perspectives on directions to optimize, including the device structure and the organic and perovskite layers. This review serves as an ideal guide for the further development of high-performance integrated photovoltaic devices.