Decay mechanisms in CdS buffered Cu In,Ga Se2 thin film solar cells after exposure to thermal stress Understanding the role of Na
Autor: | Hasan A. Yetkin, Christian A. Kaufmann, Rutger Schlatmann, Reiner Klenk, Tobias Bertram, Marin Rusu, Tim Kodalle, Bernd Szyszka, Alejandra Villanueva-Tovar |
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Rok vydání: | 2021 |
Předmět: |
Materials science
Tandem Renewable Energy Sustainability and the Environment business.industry Annealing (metallurgy) Band gap Diffusion Condensed Matter Physics Copper indium gallium selenide solar cells Acceptor Electronic Optical and Magnetic Materials Optoelectronics Degradation (geology) Thermal stability Photovoltaics and Wind Energy Electrical and Electronic Engineering business |
Popis: | Due to their tunable bandgap energy, Cu(In,Ga)Se2 (CIGSe) thin‐film solar cells are an attractive option for use as bottom devices in tandem configurations. In monolithic tandem devices, the thermal stability of the bottom device is paramount for reliable application. Ideally, it will permit the processing of a top device at the required optimum process temperature. Here, we investigate the degradation behavior of chemical bath deposited (CBD) CdS‐buffered CIGSe thin‐film solar cells with and without Na incorporation under thermal stress in ambient air and vacuum with the aim to gain a more detailed understanding of their degradation mechanisms. For the devices studied, we observe severe degradation after annealing at 300°C independent of the atmosphere. The electrical and compositional properties of the samples before and after a defined application of thermal stress are studied. In good agreement with literature reports, we find pronounced Cd diffusion into the CIGS absorber layer. In addition, for Na‐containing samples, the observed degradation can be mainly explained by the formation of Na‐induced acceptor states in the TCO front contact and a back contact barrier formation due to the out‐diffusion of Na. Supported by numerical device simulation using SCAPS‐1D, various possible degradation models are discussed and correlated with our findings. |
Databáze: | OpenAIRE |
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