Regensburg 2025 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 1: Perovskite and Photovoltaics I (joint session HL/KFM)
HL 1.2: Vortrag
Montag, 17. März 2025, 09:45–10:00, H13
Compositional Engineering of Mixed-Metal Chalcohalides for Photovoltaic Applications — •Pascal Henkel1, Jingrui Li2, and Patrick Rinke1,3 — 1Department of Applied Physics, Aalto University, P.O.Box 11100, 00076 AALTO, Finland — 2School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China — 3Technical University of Munich, 85748 Garching, Germany
Perovskite-inspired quaternary mixed-metal chalcohalides (MMCHs, M(II)2M(III)Ch2X3) are an emerging materials class for photovoltaic’s [1], that could overcome the stability and toxicity problems of halid perovskites [2], and still deliver high conversion efficiencies [3]. Compositional engineering enables the optimization of MMCH materials properties en route to commercialization.
We study the stability of MMCH alloys for three different compositional positions: the M(III), the Ch and the X site. We use a combination of density functional theory and machine learning to explore the compositional space of the alloys [4] and to compute their convex hulls. For x site alloying, for example [Sn2InS2(Br1−cIc)3], we obtained stable structures for c = 1/3 and c = 2/3 for the Cmcm phase and for c = 1/6 and c = 1/3 for the Cmc21 phase, but not for P21/c. The energetically favored structures (at c = 1/3) are highly symmetrical and exhibit a layered pattern. Every third halogen layer is fully occupied by iodine whereas the other two layers are filled with bromine.
[1] Chem. Mater. 35, 7761-7769 (2023), [2] Z. Anorg. Allg. Chem. 468, 91-98 (1980), [3] Mater. Horiz. 8, 2709 (2021). [4] Phys. Rev. Materials 6, 113801 (2024).
Keywords: material design; compositional engineering; perovskite-inspired materials; mixed-metal chalcohalides; machine learning