Sequentially processed quaternary blends for high-performance indoor organic photovoltaic applications

Multicomponent blends, such as quaternary bulk heterojunctions (BHJs), promise high-performance indoor organic photovoltaics (OPVs) with composition-dependent optoelectronic and morphological properties. However, an elaborate optimization of numerous parameters for solution processing and molecular control remains quite challenging. Herein, sequential deposition is demonstrated as a method for the facile fabrication of modified quaternary BHJ layers for high-performance indoor OPV applications. Without any optimization and treatment steps, a simple consecutive spin-coating of two binary donor:acceptor blend solutions produced quaternary BHJ films showing effective absorption at visible-light wavelengths with no significant compromise in the spectral response of components. In addition, the improved photon collection was accompanied by an alleviated hole trap-state density and charge recombination loss, which resulted from the improved molecular ordering and orientation of the polymers. Thus, the sequentially processed OPVs exhibited superior photovoltaic operation under diverse low-intensity indoor irradiation environments. Sequential deposition can serve as a platform to achieve high-performance multicomponent BHJ OPVs for emerging indoor applications, while overcoming the technical and economic shortcomings of conventional multicomponent BHJ OPVs.