Wafer‐Scale Radial Junction Solar Cells with 21.1% Efficiency Using <i>c</i>‐Si Microwires
Deokjae Choi, Inchan Hwang, Youri Lee, Myounghyun Lee, Han‐Don Um, Kwanyong Seo
Abstract
Abstract Microwire (MW)‐based radial junction crystalline silicon ( c ‐Si) solar cells have great potential as an emerging energy device with an efficiency of over 20%. However, the competitive efficiency of MW‐based c ‐Si solar cells in realizing a wafer‐scale device is limiting its commercialization. In this study, the aim is to demonstrate that conventional fabrication techniques can be applied to MW‐based solar cells while not only increasing the size from the lab‐scale to the wafer‐scale but also retaining an efficiency of >20%. Surprisingly, an improvement in open‐circuit voltage and fill factor is observed with an increase in device size, due to the reduction of recombination loss at the device edge. Finally, a successful demonstration of 21.1% efficiency at 4‐inch wafer‐scale (25 cm 2 ) in c ‐Si MW solar cell is observed, while an efficiency of 20.6% at a lab‐scale size (1 cm 2 ) is observed.