Abstract
Interlayer excitons (IXs) at the interface of heterostructures (HSs) with a staggered band alignment are fascinating quantum quasi-particles with light-emitting and long-lifetime characteristics. In this study, the energy band alignments (EBAs) of the HS of MAPbI3 perovskite thin sheets with CdSe-ZnS core–shell quantum dot (QD) layers are modulated by using different diameters of the QDs. Far-red IX emission is observed at 1.42 eV from the HS of MAPbI3/CdSe-ZnS-QD (λem = 645 nm) with type-II EBA owing to charge transfer. The lifetime of the far-red IXs is estimated to be 5.68 µs, which is considerably longer than that (0.715 ns) of the intralayer excitons from CdSe-ZnS-QD. With increasing incident excitation power, the PL peak and its intensity of IXs are blue-shifted and linearly increased, respectively, indicating a strong dipole alignment of far-red IXs at the heterojunction. Back focal plane imaging suggests that the directions of dipole moments of the IXs are relatively out-of-plane compared to those of the intralayer excitons (MAPbI3 and CdSe-ZnS-QD). Notably, the abnormal behavior of the optical characteristics is observed near the phase transition temperature (90 K) of MAPbI3. MAPbI3/CdSe-ZnS-QD HS photodetectors show the increase in photocurrent and detectivity compared to MAPbI3 at IX excitation.
Original language | English |
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Article number | 2207653 |
Journal | Advanced Science |
Volume | 10 |
Issue number | 14 |
DOIs | |
Publication status | Published - 2023 May 17 |
Keywords
- charge transfer
- far-red
- interlayer exciton
- optoelectronics
- perovskite
- quantum dots
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Chemical Engineering(all)
- Materials Science(all)
- Biochemistry, Genetics and Molecular Biology (miscellaneous)
- Engineering(all)
- Physics and Astronomy(all)