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Title: Superlattices are Greener on the Other Side: How Light Transforms Self-Assembled Mixed Halide Perovskite Nanocrystals

Journal Article · · ACS Energy Letters

Perovskite nanocrystal superlattices (NC SLs) are the nearest real-world approximations to monodisperse NC ensembles. NC SLs thus represent ideal model systems for evaluating the optical and structural stability of CsPb(I1–xBrx)3 NCs at a macroscopic level. Here, photoinduced changes to CsPb(I1–xBrx)3 NC SLs (0 < x < 1.0) are probed via in situ photoluminescence, X-ray diffraction, and electron microscopy. We find that prolonged (~10–20 h) ultraviolet–visible irradiation causes irreversible PL blueshifts, photobrightening, and crystal structure contractions. These changes stem from gradual photoinduced I2 sublimation, which transforms CsPb(I1–xBrx)3 into CsPbBr3. Despite eliminating half of the initial halides from individual CsPb(I0.53Br0.47)3 particles, NCs within SLs remarkably preserve their initial crystallinity, cuboidal shapes, edge lengths, and size distributions. This work illustrates compositional control toward generating precisely engineered perovskite NC SLs. It also highlights iodide photo-oxidation as a hurdle that must be overcome if mixed halide perovskite nanomaterials are to be applied beyond fundamental studies.

Research Organization:
University of Notre Dame, IN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; European Union’s Horizon 2020
Grant/Contract Number:
SC0014334; FC02-04ER15533; 794560
OSTI ID:
1659522
Alternate ID(s):
OSTI ID: 1657793
Journal Information:
ACS Energy Letters, Vol. 5, Issue 5; ISSN 2380-8195
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 41 works
Citation information provided by
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