Probing the gamma-scintillation process in semiconductor nanomaterials using ultrafast transient cathodoluminescence

Jeffrey M. Pietryga, Lazaro A. Padilha, Wan Ki Bae, Victor I Klimov, Richard D Schaller

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Energy-resolving gamma-ray detectors are of particular interest for the detection of illicit radioactive materials at border crossings and other portals because they offer fast, contactless screening that can discriminate between dangerous and benign materials. Among detector classes, scintillators offer an intriguing balance between cost and performance, but current technologies rely on single-crystal materials that are not scalable to portal-relevant detector sizes. Thus, there is a recognized need for novel, processible, high-performance scintillating materials or composites. Composites based on semiconductor nanocrystal quantum dots (QDs) are of interest because of their potentially high gamma-stopping power, high emission quantum yields, and low-cost solution synthesis and processing. Yet the performance of these and other granular nanomaterials has not met expectations. We suggest that this is due to the general lack of insight into the gamma-to-photons transduction process within these inherently more complex materials, which reduces the development and refinement of candidates to simple trial-and-error. Here, we describe the development of ultrafast transient cathodoluminescence as a unique spectroscopic tool for probing the population of excited states formed within a material during scintillation, and thus determining the major sources of energy loss. Our analysis shows that in the case of CdSe/ZnS core/shell QDs, any efficiency loss due to previously blamed factors of low-stopping power and high reabsorptive losses are likely dwarfed by the losses attributable to efficient, non-radiative Auger recombination. We examine how we reached this conclusion, and how this insight defines the characteristics needed in the next generation of scintillating QD composites.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Volume8710
DOIs
Publication statusPublished - 2013
EventChemical, Biological, Radiological, Nuclear, and Explosives (CBRNE) Sensing XIV - Baltimore, MD, United States
Duration: Apr 30 2013May 3 2013

Other

OtherChemical, Biological, Radiological, Nuclear, and Explosives (CBRNE) Sensing XIV
CountryUnited States
CityBaltimore, MD
Period4/30/135/3/13

Fingerprint

Nanomaterials
Cathodoluminescence
Scintillation
cathodoluminescence
Nanostructured materials
scintillation
Semiconductors
quantum dots
stopping power
Semiconductor materials
composite materials
detectors
Semiconductor quantum dots
Quantum Dots
radioactive materials
Detectors
Composite
Detector
borders
Composite materials

Keywords

  • Cathodoluminescence
  • Charged nanocrystal
  • Multiexciton
  • Nanocrystal
  • Quantum dot
  • Radiation detection

ASJC Scopus subject areas

  • Applied Mathematics
  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Pietryga, J. M., Padilha, L. A., Bae, W. K., Klimov, V. I., & Schaller, R. D. (2013). Probing the gamma-scintillation process in semiconductor nanomaterials using ultrafast transient cathodoluminescence. In Proceedings of SPIE - The International Society for Optical Engineering (Vol. 8710). [87101G] https://doi.org/10.1117/12.2015495

Probing the gamma-scintillation process in semiconductor nanomaterials using ultrafast transient cathodoluminescence. / Pietryga, Jeffrey M.; Padilha, Lazaro A.; Bae, Wan Ki; Klimov, Victor I; Schaller, Richard D.

Proceedings of SPIE - The International Society for Optical Engineering. Vol. 8710 2013. 87101G.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Pietryga, JM, Padilha, LA, Bae, WK, Klimov, VI & Schaller, RD 2013, Probing the gamma-scintillation process in semiconductor nanomaterials using ultrafast transient cathodoluminescence. in Proceedings of SPIE - The International Society for Optical Engineering. vol. 8710, 87101G, Chemical, Biological, Radiological, Nuclear, and Explosives (CBRNE) Sensing XIV, Baltimore, MD, United States, 4/30/13. https://doi.org/10.1117/12.2015495
Pietryga JM, Padilha LA, Bae WK, Klimov VI, Schaller RD. Probing the gamma-scintillation process in semiconductor nanomaterials using ultrafast transient cathodoluminescence. In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 8710. 2013. 87101G https://doi.org/10.1117/12.2015495
Pietryga, Jeffrey M. ; Padilha, Lazaro A. ; Bae, Wan Ki ; Klimov, Victor I ; Schaller, Richard D. / Probing the gamma-scintillation process in semiconductor nanomaterials using ultrafast transient cathodoluminescence. Proceedings of SPIE - The International Society for Optical Engineering. Vol. 8710 2013.
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