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Proceedings Paper

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

Paper Abstract

The concept of condensed phase optical cooling has existed for nearly 90 years ever since Pringsheim proposed a conceptual approach for cooling 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 low background absorption. Until recently, solid state 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. 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 via the involvement of donor-acceptor states.

Paper Details

Date Published: 14 March 2018
Proc. SPIE 10550, Optical and Electronic Cooling of Solids III, 105500C (14 March 2018); doi: 10.1117/12.2290468
Show Author Affiliations
Masaru K. Kuno, Univ. of Notre Dame (United States)
Yurii Morozov, Univ. of Notre Dame (United States)

Published in SPIE Proceedings Vol. 10550:
Optical and Electronic Cooling of Solids III
Richard I. Epstein; Denis V. Seletskiy; Mansoor Sheik-Bahae, Editor(s)

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