Identifying Suitable Front Contacts for High‐Efficiency Cd(Se,Te) Solar Cells on Space‐Qualified Cover Glass

ABSTRACT

Deployment of photovoltaics in space requires devices that combine high‐efficiency, low areal mass, and resilience to harsh environments. Historically, high‐efficiency multijunction III–V materials have dominated space power systems; however, their high cost and limited manufacturing throughput motivate the exploration of scalable alternatives. While CdTe‐based thin‐film photovoltaics offer an attractive option, their performance on non‐conventional substrates can suffer from front contact instability under higher‐temperature processing. Here, the role of front contact chemistry in limiting cell performance is investigated using CdTe‐based devices fabricated on 150 μm thick Ceria‐doped space‐qualified 0214 Corning glass. A matrix of four transparent conducting oxides (TCOs: CTO, AZO, ITO, IZO) combined with two n‐type emitters (MZO, IGO) reveals chemical stability at the front interface—rather than absorber composition alone—governs recombination losses, voltage deficits, and device reproducibility. Chemically stable front contact combinations suppress elemental diffusion and interfacial degradation, resulting in significantly improved carrier lifetimes and junction quality. These insights are validated through record‐certified Cd(Se,Te) cell efficiencies of 18.4% under AM1.5G and 16.2% under AM0 illumination on ultra‐thin glass. Beyond CdTe, this work provides a general framework for the rational selection of TCO/emitter interfaces in superstrate thin‐film photovoltaics, including emerging technologies like metal halide perovskites, while enabling high‐efficiency, lightweight photovoltaics for space applications.