Optical cooling at the optimal SPR angle of a glass–ITO–CdSe/ZnS(QDs) interface

Abstract

In practice, cooling effects must dominate over heating associated with nonradiative decay and multiphonon emission to attain optical cooling in semiconductors. Although quantum confinement nanostructures (e.g., quantum dots [QDs]) have been used to reduce the self-absorption of anti-Stokes luminescence, their low quantum efficiency precludes high light extraction, thus reducing net cooling generation. Superficial plasmon resonance (SPR) generated in some metal–dielectric interfaces provides an efficient way to tune and enhance the optical properties and photoluminescence (PL) of QDs. In this work, the optimal SPR angle (θSPR) was used to enhance the PL of CdSe/ZnS core–shell QDs, and hence their cooling properties, in a glass–indium tin oxide–QD interface. Three excitation wavelengths (λexc = 405, 532, and 640 nm) were used to evaluate the cooling properties. The best results were obtained when λexc = 640 nm. A PL increment and temperature decrement (Δt) of 2-fold and 4 °C, respectively, were obtained at θSPR in 50 min due to the generation of anti-Stokes PL by the QDs and the enlargement of such generated PL because of the presence of the SPR effect at the interface.