A glass thinning and texturing method for light incoupling in thin-film polycrystalline silicon solar cells application

Abstract

For polycrystalline silicon (poly-Si) thin-film solar cells on ∼3 mm borosilicate glass, glass thinning reduces the glass absorption and light leaking to neighbouring cells; the glass texturing of the sun-facing side suppresses reflection. In this Letter, a labour-free wet etching method is developed to texture and thin the glass at the same time in contrast to conventionally separated labour-intensive glass thinning and texturing processes. For 2 cm2 size poly-Si thin-film solar cells on glass superstrate, this wet etching successfully thins down the glass from 3 mm to 0.5 mm to check the ultimate benefit of the process and introduces a large micron texture on the sun-facing glass surface. The process enhances Jsc by 6.3% on average, with the optimal Jsc enhancement of 8%, better than the value of 4.6% found in the literature. This process also reduces the loss in external quantum efficiency (EQE loss), which is due to light leaking to neighbouring cells, dramatically. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)