Development of Highly Stable and Efficient Amorphous Silicon Based Solar Cells

The suppression of the light-induced degradation of a-Si:H is one of the biggest challenges to make significant progress in thin-film solar cells. In this contribution, we report on recent developments of highly stable and efficient a-Si:H solar cells whose absorber layers were grown by a remote plasma process using a triode PECVD technique. Although the deposition rate is relatively low (0.01-0.05 nm/s) compared to the conventional diode-type PECVD process (~0.2 nm/s), the light-induced degradation in conversion efficiency (/ini) is substantially reduced. As a result, stabilized efficiencies of nearly 10% are obtained over the wide range of absorber layer thicknesses (ti~150-390 nm). An a-Si:H single-junction p-i-n solar cell (ti~220 nm, area: 0.999 cm2) with a stabilized efficiency of 10.11% has been confirmed by Calibration, Standards and Measurement Team of AIST. This solar cell shows relative efficiency degradation of 11% under AM1.5G 100 mW/cm2 illumination at cell temperature of 50 °C for 1000 h.