Emergent Midgap Excitons in Large-Size Freestanding 2D Strongly Correlated Perovskite Oxide Films

Yuguo Zhang; Haijiao Harsan Ma; Xin Gan; Yupeng Hui; Yueying Zhang; Jie Su; Ming Yang; Zhaosheng Hu; Juanxiu Xiao; Xiaoli Lu; Jincheng Zhang; Yue Hao

doi:10.1002/adom.202100025

Emergent Midgap Excitons in Large-Size Freestanding 2D Strongly Correlated Perovskite Oxide Films

Yuguo Zhang, Haijiao Harsan Ma, Xin Gan, Yupeng Hui, Yueying Zhang, Jie Su, Ming Yang, Zhaosheng Hu, Juanxiu Xiao, Xiaoli Lu, Jincheng Zhang, Yue Hao

Research output: Journal article publication › Journal article › Academic research › peer-review

4 Citations (Scopus)

Abstract

2D materials exhibit strong excitonic effects due to low dimensionality and enhanced Coulomb interactions, resulting in fascinating many-particle phenomena like excitons. Though perovskite is a classical type of material hosting abundant correlated electronic phases, freestanding 2D perovskite oxides are not easy to fabricate and yet to be extensively studied. Here the realization of large size (1 × 1 cm²) freestanding perovskite SrTiO₃ films, which show unexpected excitonic photoluminescence (PL) spectra and carrier dynamics, is reported. Two pronounced broad PL peaks emerge in 2D freestanding SrTiO₃ films at 2.34–2.4 and 1.8–1.9 eV, of which the 2.34–2.4 eV emission originates from self-trapped excitons localized within TiO₆ octahedra, and the 1.8–1.9 eV peak from Ti vacancies. The time-resolved PL shows a remarkable enhancement of nonradiative Auger recombination through three-particle process, in which electron–hole excitons transfer their kinetic energy to other free electrons or holes. The results demonstrate unique excitonic properties in 2D perovskite SrTiO₃ films and unravel their potential for high-performance optoelectronic devices.

Original language	English
Article number	2100025
Journal	Advanced Optical Materials
Volume	9
Issue number	10
DOIs	https://doi.org/10.1002/adom.202100025
Publication status	Published - 19 May 2021

Keywords

2D materials
excitons
localization
perovskites
strontium titanate

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Atomic and Molecular Physics, and Optics

More information

10.1002/adom.202100025

Cite this

@article{83a70fd3d3524bcca1671d0908298b8e,

title = "Emergent Midgap Excitons in Large-Size Freestanding 2D Strongly Correlated Perovskite Oxide Films",

abstract = "2D materials exhibit strong excitonic effects due to low dimensionality and enhanced Coulomb interactions, resulting in fascinating many-particle phenomena like excitons. Though perovskite is a classical type of material hosting abundant correlated electronic phases, freestanding 2D perovskite oxides are not easy to fabricate and yet to be extensively studied. Here the realization of large size (1 × 1 cm2) freestanding perovskite SrTiO3 films, which show unexpected excitonic photoluminescence (PL) spectra and carrier dynamics, is reported. Two pronounced broad PL peaks emerge in 2D freestanding SrTiO3 films at 2.34–2.4 and 1.8–1.9 eV, of which the 2.34–2.4 eV emission originates from self-trapped excitons localized within TiO6 octahedra, and the 1.8–1.9 eV peak from Ti vacancies. The time-resolved PL shows a remarkable enhancement of nonradiative Auger recombination through three-particle process, in which electron–hole excitons transfer their kinetic energy to other free electrons or holes. The results demonstrate unique excitonic properties in 2D perovskite SrTiO3 films and unravel their potential for high-performance optoelectronic devices.",

keywords = "2D materials, excitons, localization, perovskites, strontium titanate",

author = "Yuguo Zhang and Ma, {Haijiao Harsan} and Xin Gan and Yupeng Hui and Yueying Zhang and Jie Su and Ming Yang and Zhaosheng Hu and Juanxiu Xiao and Xiaoli Lu and Jincheng Zhang and Yue Hao",

note = "Funding Information: Y.Z. and H.H.M. contributed equally to this work. The authors thank the National Science Foundation (NSF) of China Grant No. 61904140 for financial support. The authors acknowledge Lv Ruichan, Bu Yuyu, and Jia Renxu for help with the measurements and useful discussions. J.X. acknowledges financial support of National Natural Science Foundation of China (NSFC), Grant No. 52002100, the High‐level Talent Project of Hainan Natural Science Foundation (Grant No. 2019RC075), and the Start‐up Research Foundation of Hainan University (Grant No. KYQD(ZR)1816]. M.Y. would like to acknowledge the computational resource supported by the Centre of Advanced 2D Materials, National University of Singapore. Publisher Copyright: {\textcopyright} 2021 Wiley-VCH GmbH",

year = "2021",

month = may,

day = "19",

doi = "10.1002/adom.202100025",

language = "English",

volume = "9",

journal = "Advanced Optical Materials",

issn = "2195-1071",

publisher = "John Wiley and Sons Inc.",

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TY - JOUR

T1 - Emergent Midgap Excitons in Large-Size Freestanding 2D Strongly Correlated Perovskite Oxide Films

AU - Zhang, Yuguo

AU - Ma, Haijiao Harsan

AU - Gan, Xin

AU - Hui, Yupeng

AU - Zhang, Yueying

AU - Su, Jie

AU - Yang, Ming

AU - Hu, Zhaosheng

AU - Xiao, Juanxiu

AU - Lu, Xiaoli

AU - Zhang, Jincheng

AU - Hao, Yue

N1 - Funding Information: Y.Z. and H.H.M. contributed equally to this work. The authors thank the National Science Foundation (NSF) of China Grant No. 61904140 for financial support. The authors acknowledge Lv Ruichan, Bu Yuyu, and Jia Renxu for help with the measurements and useful discussions. J.X. acknowledges financial support of National Natural Science Foundation of China (NSFC), Grant No. 52002100, the High‐level Talent Project of Hainan Natural Science Foundation (Grant No. 2019RC075), and the Start‐up Research Foundation of Hainan University (Grant No. KYQD(ZR)1816]. M.Y. would like to acknowledge the computational resource supported by the Centre of Advanced 2D Materials, National University of Singapore. Publisher Copyright: © 2021 Wiley-VCH GmbH

PY - 2021/5/19

Y1 - 2021/5/19

N2 - 2D materials exhibit strong excitonic effects due to low dimensionality and enhanced Coulomb interactions, resulting in fascinating many-particle phenomena like excitons. Though perovskite is a classical type of material hosting abundant correlated electronic phases, freestanding 2D perovskite oxides are not easy to fabricate and yet to be extensively studied. Here the realization of large size (1 × 1 cm2) freestanding perovskite SrTiO3 films, which show unexpected excitonic photoluminescence (PL) spectra and carrier dynamics, is reported. Two pronounced broad PL peaks emerge in 2D freestanding SrTiO3 films at 2.34–2.4 and 1.8–1.9 eV, of which the 2.34–2.4 eV emission originates from self-trapped excitons localized within TiO6 octahedra, and the 1.8–1.9 eV peak from Ti vacancies. The time-resolved PL shows a remarkable enhancement of nonradiative Auger recombination through three-particle process, in which electron–hole excitons transfer their kinetic energy to other free electrons or holes. The results demonstrate unique excitonic properties in 2D perovskite SrTiO3 films and unravel their potential for high-performance optoelectronic devices.

AB - 2D materials exhibit strong excitonic effects due to low dimensionality and enhanced Coulomb interactions, resulting in fascinating many-particle phenomena like excitons. Though perovskite is a classical type of material hosting abundant correlated electronic phases, freestanding 2D perovskite oxides are not easy to fabricate and yet to be extensively studied. Here the realization of large size (1 × 1 cm2) freestanding perovskite SrTiO3 films, which show unexpected excitonic photoluminescence (PL) spectra and carrier dynamics, is reported. Two pronounced broad PL peaks emerge in 2D freestanding SrTiO3 films at 2.34–2.4 and 1.8–1.9 eV, of which the 2.34–2.4 eV emission originates from self-trapped excitons localized within TiO6 octahedra, and the 1.8–1.9 eV peak from Ti vacancies. The time-resolved PL shows a remarkable enhancement of nonradiative Auger recombination through three-particle process, in which electron–hole excitons transfer their kinetic energy to other free electrons or holes. The results demonstrate unique excitonic properties in 2D perovskite SrTiO3 films and unravel their potential for high-performance optoelectronic devices.

KW - 2D materials

KW - excitons

KW - localization

KW - perovskites

KW - strontium titanate

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U2 - 10.1002/adom.202100025

DO - 10.1002/adom.202100025

M3 - Journal article

AN - SCOPUS:85104263514

SN - 2195-1071

VL - 9

JO - Advanced Optical Materials

JF - Advanced Optical Materials

IS - 10

M1 - 2100025

ER -

Emergent Midgap Excitons in Large-Size Freestanding 2D Strongly Correlated Perovskite Oxide Films

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Keywords

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