Flexible crystalline silicon photovoltaics with vertically aligned microwire array

Abstract

The flexible photovoltaic (FPV) devices that can be installed on curved or bendable surfaces have been actively investigated to integrate them into various portable electronic devices as a continuous power source. Here, we demonstrate highly efficient flexible crystalline Si PV with vertically aligned microwire arrays (MWA). The fabricated flexible thin c-Si PV with 20 μm MWA shows surprising flexibility with a bending radius of 10 mm. To diminish the light reflection of flat-top-area of MWA, we apply the tapered MWA formed via wet-etching process, and thus the surface reflection was drastically reduced from 12% to around 1%. Consequently, our best device with the 20 μm tapered MWA shows a maximum efficiency of 16.8% and very stable photovoltaic properties during the repeated bending tests up to 1000 times. Notifying that electronic watch and fan integrated with our flexible solar cells were successfully operated during the repeated bending under illumination. Hence, we believe that our proposed flexible solar cell can lead the market of flexible photovoltaic devices based on the high efficiency and stable flexibility.