Wild Band Edges: The Role of Bandgap Grading and Band-Edge Fluctuations in High-Efficiency Chalcogenide Devices: Preprint
Band-edge effects -- including grading, electrostatic fluctuations, bandgap fluctuations, and band tails -- affect chalcogenide device efficiency. These effects now require more careful consideration as efficiencies increase beyond 20%. Several aspects of the relationships between band-edge phenomena and device performance for NREL absorbers are examined. For Cu(In,Ga)Se2 devices, recent increases in diffusion length imply changes to optimum bandgap profile. The origin, impact, and modification of electrostatic and bandgap fluctuations are also discussed. The application of the same principles to devices based on CdTe, kesterites, and emerging absorbers (Cu2SnS3, CuSbS2), considering differences in materials properties and defect formation energies, is examined.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1258569
- Report Number(s):
- NREL/CP-5J00-65682
- Resource Relation:
- Conference: Presented at the 43rd IEEE Photovoltaic Specialists Conference, 5-10 June 2016, Portland, Oregon
- Country of Publication:
- United States
- Language:
- English
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