Journal article
Optical Signatures of Transiently Disordered Semiconductor Nanocrystals
ACS nano, v 12(10), pp 10008-10015
23 Oct 2018
PMID: 30226751
Abstract
D The optoelectronic properties of semiconductor nanocrystals (NCs) have led to efforts to integrate them as the active material in light-emitting diodes, solid-state lighting, and lasers. Understanding related high carrier injection conditions is therefore critical as resultant thermal effects can impact optical properties. The physical integrity of NCs is indeed questionable as recent transient X-ray diffraction studies have suggested that nanoscopic particles reversibly lose crystalline order, or melt, under high fluence photoexcitation. Informed by such studies, here, we examine CdSe NCs under elevated fluences to determine the impact of lattice disordering on optical properties. To this end, we implement intensity-dependent transient absorption using both one- and two-pump methods where the latter effectively subtracts out the NC optical signatures associated with lower fluence photoexcitation, especially band-edge features. At elevated fluences, we observe a long-lived induced absorption at a lower energy than the crystalline-NC bandgap across a wide range of sizes that follows power-dependent trends and kinetics consistent with the prior transient X-ray measurements. NC photoluminescence studies provide further evidence that melting influences optical properties. These methods of characterizing bandgap narrowing caused by lattice disordering could facilitate routes to improved optical amplification and band-edge emission at high excitation density.
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Details
- Title
- Optical Signatures of Transiently Disordered Semiconductor Nanocrystals
- Creators
- Matthew S. Kirschner - Northwestern UniversityBenjamin T. Diroll - Argonne National LaboratoryAlexandra Brumberg - Northwestern UniversityAriel A. Leonard - Northwestern UniversityDaniel C. Hannah - Northwestern UniversityLin X. Chen - Northwestern UniversityRichard D. Schaller - Northwestern UniversityArgonne National Laboratory (ANL), Argonne, IL (United States)
- Publication Details
- ACS nano, v 12(10), pp 10008-10015
- Publisher
- Amer Chemical Soc
- Number of pages
- 8
- Grant note
- Ultrafast Initiative of the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, through Argonne National Laboratory; United States Department of Energy (DOE) DGE-1324585 / National Science Foundation Graduate Research Fellowship Program; National Science Foundation (NSF) DE-AC02-06CH11357 / U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences; United States Department of Energy (DOE)
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Chemistry
- Web of Science ID
- WOS:000448751800038
- Scopus ID
- 2-s2.0-85054354838
- Other Identifier
- 991022053793004721
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Chemistry, Multidisciplinary
- Chemistry, Physical
- Materials Science, Multidisciplinary
- Nanoscience & Nanotechnology