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 publicationJournal articleAcademic researchpeer-review

3 Citations (Scopus)


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 languageEnglish
Article number2100025
JournalAdvanced Optical Materials
Issue number10
Publication statusPublished - 19 May 2021


  • 2D materials
  • excitons
  • localization
  • perovskites
  • strontium titanate

ASJC Scopus subject areas

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


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