Control of photoluminescence of CdSe/ZnS quantum dots in a nematic liquid crystal by an electric field

• Published in: Optics and spectroscopy 2015-11, Vol.119 (5), p.812-815
• Main Authors: Kurochkina, M. A., Shcherbinin, D. P., Konshina, E. A.
• Format: Article
• Language: English
• Subjects: Condensed-Matter Spectroscopy; Lasers; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy
• ISSN: 0030-400X; 1562-6911
• DOI: 10.1134/S0030400X15110168

Photoluminescence (PL) spectra of a nematic liquid crystal suspension doped with 10 wt % CdSe/ZnS semiconductor quantum dots (QDs) with a core size of 3.5 nm in a 20-µm thick plane-parallel cell have been investigated. The spectrum of a homogeneously oriented suspension layer exhibits a significant shift of the PL peak by ~83 nm to a wavelength of 676 nm as compared with the QD spectrum in toluene. The application of a dc electric field with a strength of 0.25 V/µm to the cell leads to a slight hypsochromic shift of this peak, the position of which does not change with a further increase in the field strength up to 2 V/µm. The PL intensity changes exponentially and decreases by a factor of two at the field strength of 1 V/µm. The mechanism of PL quenching of QDs in a homogeneously oriented layer of nematic liquid crystal is discussed.