Near-infrared organic photoelectric materials for lightharvesting systems: Organic photovoltaics and organic photodiodes

The inherent advantages of organic optoelectronic materials endow lightharvesting systems,including organic photovoltaics(OPVs)and organic photodiodes(OPDs),with multiple advantages,such as low-cost manufacturing,light weight,flexibility,and applicability to large-area fabrication,make them promising competitors with their inorganic counterparts.Among them,nearinfrared(NIR)organic optoelectronic materials occupy a special position and have become the subject of extensive research in both academia and industry.The introduction of NIR materials into OPVs extends the absorption spectrum range,thereby enhancing the photon-harvesting ability of the devices,due to which they have been widely used for the construction of semitransparent solar cells with single-junction or tandem architectures.NIR photodiodes have tremendous potential in industrial,military,and scientific applications,such as remote control of smart electronic devices,chemical/biological sensing,environmental monitoring,optical communication,and so forth.These practical and potential applications have stimulated the development of NIR photoelectric materials,which in turn has given impetus to innovation in light-harvesting systems.In this review,we summarize the common molecular design strategies of NIR photoelectric materials and enumerate their applications in OPVs and OPDs.

Stretchable transparent electrodes for conformable wearable organic photovoltaic devices

To achieve adhesive and conformable wearable electronics,improving stretchable transparent electrode(STE)becomes an indispensable bottleneck needed to be addressed.Here,we adopt a nonuniform Young’s modulus structure with silver nanowire(AgNW)and fabricate a STE layer.This layer possesses transparency of>88%over a wide spectrum range of 400–1000 nm,sheet resistance below 20Ωsq^(−1),stretchability of up to 100%,enhanced mechanical robustness,low surface roughness,and good interfacial wettability for solution process.As a result of all these properties,the STE enables the fabrication of a highly efficient ultraflexible wearable device comprising of both organic photovoltaic(OPV)and organic photodetector(OPD)parts with high mechanical durability and conformability,for energy-harvesting and biomedical-sensing applications,respectively.This demonstrates the great potential of the integration of OPVs and OPDs,capable of harvesting energy independently for biomedical applications,paving the way to a future of independent conformable wearable OPV/OPDs for different applications.