Aging of Self-Assembled Lead Halide Perovskite Nanocrystal Superlattices: Effects on Photoluminescence and Energy Transfer
Creators
- 1. Nanochemistry Department, Italian Institute of Technology, Via Morego 30, Genova 16163, Italy
- 2. CNR Nanotec, Institute of Nanotechnology, Via Monteroni, Lecce 73100, Italy
- 3. Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- 4. CNR Nanotec, Institute of Nanotechnology, Via Monteroni, Lecce 73100, Italy; Dipartimento di Matematica e Fisica "E. de Giorgi", Università Del Salento, Campus Ecotekne, Via Monteroni, Lecce 73100, Italy
- 5. Nanochemistry Department, Italian Institute of Technology, Via Morego 30, Genova 16163, Italy; International Doctoral Program in Science, Università Cattolica del Sacro Cuore, Brescia 25121, Italy
Description
Excitonic coupling, electronic coupling, and cooperative interactions in self-assembled lead halide perovskite nanocrystals were reported to give rise to a red-shifted collective emission peak with accelerated dynamics. Here we report that similar spectroscopic features could appear as a result of the nanocrystal reactivity within the self-assembled superlattices. This is demonstrated by studying CsPbBr3 nanocrystal superlattices over time with room-temperature and cryogenic micro-photoluminescence spectroscopy, X-ray diffraction, and electron microscopy. It is shown that a gradual contraction of the superlattices and subsequent coalescence of the nanocrystals occurs over several days of keeping such structures under vacuum. As a result, a narrow, low-energy emission peak is observed at 4 K with a concomitant shortening of the photoluminescence lifetime due to the energy transfer between nanocrystals. When exposed to air, self-assembled CsPbBr3 nanocrystals develop bulk-like CsPbBr3 particles on top of the superlattices. At 4 K, these particles produce a distribution of narrow, low-energy emission peaks with short lifetimes and excitation fluence-dependent, oscillatory decays. Overall, the aging of CsPbBr3 nanocrystal assemblies dramatically alters their emission properties and that should not be overlooked when studying collective optoelectronic phenomena nor confused with superfluorescence effects.
Notes
Files
acsnano.0c06595.pdf
Files
(18.7 MB)
Name | Size | Download all |
---|---|---|
md5:af3f5adec17cf51854b21e04aaa39f08
|
9.4 MB | Preview Download |
md5:ec8bc0e2b9a393fb87fbe1614043b53c
|
9.3 MB | Preview Download |
Additional details
Related works
- Is new version of
- Preprint: https://arxiv.org/abs/2008.02853 (URL)