Atomistic Origins of Enhanced Band Gap, Miscibility, and Oxidation Resistance in alpha-CsPb1-xSnxI3 Mixed Perovskite

Autor(es)

Valadares, Fernando ^[1] ; Guilhon, Ivan ^[1] ; Teles, Lara K. ^[1] ; Marques, Marcelo ^[1]

Afiliação do(s) autor(es)

^[1] Inst Tecnol Aeronaut ITA, Grp Mat Semicond & Nanotecnol GMSN, BR-12228900 Sao Jose Dos Campos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 124, n. 48, p. 26124-26133, DEC 3 2020.
• Citações Web of Science: 0

Resumo

The advance made in perovskite-based solar cell technology demands the search for materials with better properties, namely, high stability in operational conditions and suitable electronic structure parameters. In this work, we provide a detailed study for cubic CsPb1-xSnxI3 alloys. We employed a theoretical model that combines quasiparticle effects via the density functional theory (DFT)-1/2 method and spin-orbit corrections with a rigorous statistical disordered description of the alloy. As the main result, a reliable quantitative expression for the variation of energy gap with the composition that can be directly compared with experiments is given. A particular situation is verified for x = 0.80, where the alloy is predicted to have a band gap of 0.984, 0.033 eV lower than the gap of CsSnI3. Additionally, the model encompasses the nuances necessary to understand the properties' behavior in this complex system. We verified that ``more mixed{''} configurations are energetically favored, leading to ordering in very small temperatures that evolve to a very stable alloy in the usual growth conditions. Also, based on the thermodynamic results, an antioxidant mechanism for this alloy is proposed. The bowing mechanism is explained in terms of band character and spin-orbit interaction. Finally, the conclusions support CsPb1-xSnxI3 alloys as a very good potential candidate for photovoltaic applications. (AU)

• Processo FAPESP: 06/05858-0 - Estudo teórico de ligas semicondutoras com aplicações em spintrônica e optoeletrônica
• Beneficiário: Lara Kühl Teles
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 12/50738-3 - Estudo de pontos quânticos através de cálculos de primeiros princípios
• Beneficiário: Ronaldo Rodrigues Pelá
• Modalidade de apoio: Auxílio à Pesquisa - Regular