>23% High-Efficiency Tunnel Oxide Junction Bifacial Solar Cell With Electroplated Cu Gridlines

Based on the metal-insulator-semiconductor concept, Triex cell is a proprietary device structure that combines a tunnel oxide junction with doped a-Si thin-film emitter layers on n-type Czochralski silicon wafers. A simple patterning process is used along with cost-effective copper electrochemical plating to form the electrodes. This paper reports a >23% high-efficiency Triex solar cell, postoptimizing key process areas to improve passivation, junction quality, and shading effects. High open-circuit voltage (V
_oc
) of 739 mV and good fill factor of 80.5% have been demonstrated on a 6-in solar cell. A champion 380-W Triex bifacial module is also validated under standard test conditions.