Vacuum-Deposited Transparent Organic Photovoltaics for Efficiently Harvesting Selective Ultraviolet and Near-Infrared Solar Energy

Abstract

Highly transparent photovoltaics (TPVs) integrated to a battery with small capacity can efficiently drive low-powered internet of things (IoT) devices such as the receivers, sensors, actuators, etc. Such see-through solar technology not only provides an opportunity to convert ambient light (sunlight or indoor lighting) to electricity but also demonstrates a concept of self-sustainable power. In this work, a selective ultraviolet/near-infrared bulk-heterojunction active layer, i.e., chloroaluminum phthalocyanine (ClAlPc) as donor and C60 as acceptor with a Cu:Ag/WO3 transparent electrode to visible lights are combined for achieving the vacuum-deposited TPVs with a power conversion efficiency of 1.34%, average visible transmission of 77.45%, and color rendering index of 91.9. Moreover, a TPV module with a working area of 1.5 cm2 is able to charge a 0.58 mAh LiFePO4(LFP)//Li battery fully within one hour under 100 mW cm-2 (≈1 sun) illumination. The TPV module can drive an exciplex organic light-emitting diode with the electroluminescence >180 cd m−2 at low illumination intensity of <5 mW cm-2. Overall, this work presents a significant step forward in the development of TPV technology towards integrating a display and storage battery, which could be successfully applied in wearable electronics requiring invisible and sustainable solar power.