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Effective band gap engineering in multi-principal oxides (CeGdLa-Zr/Hf)O_x by temperature-induced oxygen vacancies.

ABSTRACT: Oxygen vacancy control has been one of the most efficient methods to tune the physicochemical properties of conventional oxide materials. A new conceptual multi-principal oxide (MPO) is still lacking a control approach to introduce oxygen vacancies for tuning its inherent properties. Taking multi-principal rare earth-transition metal (CeGdLa-Zr/Hf) oxides as model systems, here we report temperature induced oxygen vacancy generation (OVG) phenomenon in MPOs. It is found that the OVG is strongly dependent on the composition of the MPOs showing different degrees of oxygen loss in (CeGdLaZr)O_x and (CeGdLaHf)O_x under identical high temperature annealing conditions. The results revealed that (CeGdLaZr)O_x remained stable single phase with a marginal decrease in the band gap of about 0.08 eV, whereas (CeGdLaHf)O_x contained two phases with similar crystal structure but different oxygen vacancy concentrations causing semiconductor-to-metal like transition. Due to the intrinsic high entropy, the metallic atoms sublattice in (CeGdLaHf)O_x remains rather stable, regardless of the interstitial oxygen atoms ranging from almost fully occupied (61.84 at%) to almost fully empty (8.73 at%) state in the respective crystal phases. Such highly tunable oxygen vacancies in (CeGdLa-Zr/Hf) oxides show a possible path for band gap engineering in MPOs for the development of efficient photocatalysts.

SUBMITTER: Hu Y

PROVIDER: S-EPMC9911753 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature

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Effective band gap engineering in multi-principal oxides (CeGdLa-Zr/Hf)O<sub>x</sub> by temperature-induced oxygen vacancies.

Hu Yixuan Y Anandkumar Mariappan M Joardar Joydip J Wang Xiaodong X Deshpande Atul Suresh AS Reddy Kolan Madhav KM

Scientific reports 20230209 1

Oxygen vacancy control has been one of the most efficient methods to tune the physicochemical properties of conventional oxide materials. A new conceptual multi-principal oxide (MPO) is still lacking a control approach to introduce oxygen vacancies for tuning its inherent properties. Taking multi-principal rare earth-transition metal (CeGdLa-Zr/Hf) oxides as model systems, here we report temperature induced oxygen vacancy generation (OVG) phenomenon in MPOs. It is found that the OVG is strongly ...[more]

PMID: 36759551

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Project description:Recently, lead halide perovskites have gained considerable attention by dint of their predominant physiochemical features and potential use in various applications with an improved power conversion efficiency. Despite the incredible technological and research breakthroughs in this field, most of those compounds present an obstacle to future commercialization due to their instability and extreme poisonousness. Because of this, it is preferable to replace lead with alternative stable elements to produce eco-friendly perovskites with equivalent optoelectronic qualities similar to lead-based perovskites. However, Pb-free perovskite-based devices have relatively low power conversion efficiency. Pressure might be considered an effective way for modifying the physical characteristics of these materials to enhance their performance and reveal structure-property correlations. The present study has been done to investigate the structural, electronic, optical, elastic, mechanical, and thermodynamic properties of nontoxic perovskite CsMgI3 under hydrostatic pressure by using density functional theory (DFT). At ambient pressure, the present findings are in excellent agreement with the available experimental data. Pressure causes the Mg-I and Cs-I bonds to shorten and become stronger. The absorption coefficient in the visible and ultraviolet (UV) zones grows up with the increase in pressure. Additionally, we have observed low reflectivity, a high-intensity conductivity peak, and a dielectric constant in the visible region of the electromagnetic spectrum. As pressure rises, the band gap keeps narrowing, facilitating an electron from the valence band to get excited easily at the conduction band. Furthermore, we analyze the mechanical, elastic, and thermodynamic properties under pressure, which suggests that this compound exhibit ductile behavior. The shrunk band gap and improved physical properties of CsMgI3 under hydrostatic pressure suggest that this material may be used in solar cells (for photovoltaic applications) and optoelectronic devices more frequently than at ambient pressure. In addition, this paper emphasizes the feasibility of hydrostatic pressure in the systematic modification of the optoelectronic and mechanical characteristics of lead-free halide perovskites.

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Effective band gap engineering in multi-principal oxides (CeGdLa-Zr/Hf)O_x by temperature-induced oxygen vacancies.

Publications

Effective band gap engineering in multi-principal oxides (CeGdLa-Zr/Hf)O<sub>x</sub> by temperature-induced oxygen vacancies.

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Effective band gap engineering in multi-principal oxides (CeGdLa-Zr/Hf)Ox by temperature-induced oxygen vacancies.

Publications

Effective band gap engineering in multi-principal oxides (CeGdLa-Zr/Hf)O<sub>x</sub> by temperature-induced oxygen vacancies.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

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Effective band gap engineering in multi-principal oxides (CeGdLa-Zr/Hf)O_x by temperature-induced oxygen vacancies.