Microstructure and composition of passivating interfaces in silicon heterojunction solar modules weathered in different climates

作者：Andrew G. Norman, Dirk Jordan, Steve Johnston, Glenn Teeter, Matthew Young, Steven R. Spurgeon, Dana B. Kern, Michelle A. Smeaton · 发表于：Solar Energy Materials and Solar Cells · 年份：2026 · DOI：10.1016/j.solmat.2026.114584 · 研究领域：Silicon and Solar Cell Technologies、solar cell performance optimization、Chemical and Physical Properties of Materials

Sanyo/Panasonic patented silicon heterojunction with intrinsic thin layer (HIT) solar cells in the 1990's, which demonstrated world record photovoltaic (PV) efficiency around 2014 and inspired the newer generations of silicon heterojunction technology (SHJ) as well as the current world record back-contact PV cell designs. The high-quality passivation strategy, utilizing ultra-thin layers of hydrogenated amorphous silicon (a-Si:H), leads to high voltages and long carrier lifetimes, but these qualities may degrade over time as the modules operate outdoors. Here, we investigate local microstructure and composition at the interface layers of cells from HIT modules weathered in a hot, humid climate (Florida, USA) and temperate climate (Colorado, USA) for 10 years. We employ a comprehensive set of high-resolution electron microscopy imaging and spectroscopy to directly resolve structure and composition in these cells down to the nanoscale. We show features such as alignment of the In 2 O 3 transparent conducting oxide and a-Si:H layers on the textured c-Si facets, interfacial oxidation at the a-Si:H/c-Si and In 2 O 3 /a-Si:H interfaces, and twinned c-Si resulting from epitaxial growth into the a-Si:H layer. Our results raise potential degradation mechanisms in these outdoor-weathered modules, but the root cause of electrical loss remains uncertain due to the very small changes in aged samples. This study shows that many atomic scale features at the In 2 O 3 /a-Si:H/c-Si interfaces ...