Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 42: Perovskite and Photovoltaics II (joint session HL/KFM)
HL 42.8: Talk
Thursday, March 21, 2024, 11:30–11:45, EW 203
Thermodynamics and kinetics of silver in Cu(In,Ga)Se2 solar cell absorbers — Markus Mock, •Delwin Perera, and Karsten Albe — Institut für Materialwissenschaft, Technische Universität Darmstadt, Germany
Cu(In,Ga)Se2 (CIGS) is at the moment the most efficient absorber material in thin-film solar cells. Its efficiency can be further enhanced by substituting copper with silver which increases the band gap and turns CIGS into a wide-gap semiconductor with potential application in tandem solar cells.
In this contribution, we investigate the impact of silver on structural and electronic properties of CIGS. Using semi-grand canonical Monte Carlo simulations, we explore the CIGS phase diagram as a function of silver content. In particular, we map out the phase transition between solid solution and phase decomposition as well as the spinodal region. Based on a cluster expansion model, our Monte Carlo simulations reveal the microstructure evolution within the binodal region. We supplement the thermodynamic analysis with kinetic considerations by calculating defect migration barriers and defect association energies. Finally, we investigate the effect of silver on the band gap employing hybrid density functional theory calculations.
Keywords: thin-film solar cells; CIGS; photovoltaics; cluster expansion