Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 4: Perovskite and Photovoltaics I (joint session HL/KFM)

HL 4.10: Talk

Monday, March 18, 2024, 12:15–12:30, EW 203

Exploring Mixed-Metal Chalcohalides M(II)₂M(III)Ch₂X₃ Compounds for Photovoltaic Applications — •Pascal Henkel¹, Jingrui Li², and Patrick Rinke¹ — ¹Department of Applied Physics, Aalto University, P.O.Box 11100, FI-00076 AALTO, Finland — ²School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China

New photovoltaic materials are needed to increase power conversion efficiencies (PCEs), reduce costs, and improve device longevity to facilitate the renewable energy transformation. In this context, perovskite-inspired quaternary mixed-metal chalcohalides M(II)₂M(III)Ch₂X₃ have emerged as an interesting materials class, that has the potential to overcome the stability and toxicity problems of the currently favoured halid perovskites [1], and still deliver high PCEs [2].

In this study, we apply density functional theory to identify new M(II)₂M(III)Ch₂X₃ compounds. We considered a total of 54 materials each in three different space groups (Cmcm, Cmc2₁ and P2₁/c) for which we computed the energetic stability and the band gaps with the HSE06 hybrid functional. We identified a total of 22 M(II)₂M(III)Ch₂X₃ materials, which fulfill our stability requirements and have a direct band gap in the range 0.7 eV to 2 eV. Out of the 22, 8 lead-free and 9 lead-containing materials are new [3]. Overall for all 54 compounds, P2₁/c is the thermodynamically preferred phase, whereas direct band gaps occur predominantly for Cmcm and Cmc2₁.

[1] Z. Anorg. Allg. Chem. 468, 91-98 (1980). [2] Mater. Horiz. 8, 2709 (2021), [3] Chem. Mater. 35, 7761-7769 (2023).

Keywords: material exploration; perovskite-inspired materials; mixed-metal chalcohalides M(II)2M(III)Ch2X3; density functional theory