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Proceedings Paper

Defect-mediated photoluminescence up-conversion in cadmium sulfide nanobelts (Conference Presentation)
Author(s): Yurii Morozov; Masaru K. Kuno

Paper Abstract

The concept of optical cooling of solids has existed for nearly 90 years ever since Pringsheim proposed a way to cool solids through the annihilation of phonons via phonon-assisted photoluminescence (PL) up-conversion. In this process, energy is removed from the solid by the emission of photons with energies larger than those of incident photons. However, actually realizing optical cooling requires exacting parameters from the condensed phase medium such as near unity external quantum efficiencies as well as existence of a low background absorption. Until recently, laser cooling has only been successfully realized in rare earth doped solids. In semiconductors, optical cooling has very recently been demonstrated in cadmium sulfide (CdS) nanobelts as well as in hybrid lead halide perovskites. For the former, large internal quantum efficiencies, sub-wavelength thicknesses, which decrease light trapping, and low background absorption, all make near unity external quantum yields possible. Net cooling by as much as 40 K has therefore been possible with CdS nanobelts. In this study, we describe a detailed investigation of the nature of efficient anti-Stokes photoluminescence (ASPL) in CdS nanobelts. Temperature-dependent PL up-conversion and optical absorption studies on individual NBs together with frequency-dependent up-converted PL intensity spectroscopies suggest that ASPL in CdS nanobelts is defect-mediated through involvement of defect levels below the band gap.

Paper Details

Date Published: 20 April 2017
PDF: 1 pages
Proc. SPIE 10121, Optical and Electronic Cooling of Solids II, 101210D (20 April 2017); doi: 10.1117/12.2249930
Show Author Affiliations
Yurii Morozov, Univ. of Notre Dame (United States)
Masaru K. Kuno, Univ. of Notre Dame (United States)

Published in SPIE Proceedings Vol. 10121:
Optical and Electronic Cooling of Solids II
Richard I. Epstein; Denis V. Seletskiy; Mansoor Sheik-Bahae, Editor(s)

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