Large-area Flexible Organic Solar Cells: Printing Technologies and Modular Design

Flexibility is the most prominent advantage of organic solar cells (OSCs) compared with traditional photovoltaic devices, showing an irreplaceable commercial potential. Currently, the maximum power conversion efficiencies (PCEs) of single-junction OSCs have been over 19% and 16% upon rigid and flexible substrates, respectively, which meet the criteria for commercial application. Extensive research efforts are under way, such as device configuration design, interface/photosensitive layer synthesis, transparent electrode modification and printing technology innovation, however, the reasonable selection of printing technologies, the huge performance loss of large-area printing process and the structural design of flexible modules are still the bottlenecks, limiting the commercialization of OSCs. This review focuses on the technical challenges and rational modular configuration design for printing preparation of flexible high-efficiency large-area organic devices, from the aspects of the functional layer material selection, printing process research status and large-scale efficiency losses. These will promote the integrated applications of printable organic semiconductor materials for next-generation clean energy and appeal extensive attentions in wearable electronics, building-integrated photovoltaics and Internet of Things, etc.