A newly developed-nanocrystals (ZnO and PbO) bearing silicate phosphor that emits strong bluish white-light

• Published in: Applied physics. A, Materials science & processing Vol. 124; no. 8; pp. 1 - 9
• Main Authors: Bose, Saptasree, Debnath, Radhaballabh
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2018; Springer Nature B.V
• Subjects: Applied physics; Characterization and Evaluation of Materials; Condensed Matter Physics; Dependence; Diamagnetism; Emission spectra; Excitation spectra; Machines; Manufacturing; Materials science; Nanocrystals; Nanotechnology; Optical and Electronic Materials; Physics; Physics and Astronomy; Processes; Surfaces and Interfaces; Technologists; Thin Films; Vacancies; White light; Zinc oxide
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-018-1947-0

A newly developed (ZnO nanobars and PbO nanoclusters)-containing silicate phosphor that emits strong bluish-white light, is reported. The phosphor on excitation with any light in the wavelength range of 355–370 nm, gives strong luminescence in the blue and moderately intense emissions in the green and red region-producing ultimately a strong bluish-white light. Thus, the material is unique in the sense that it gives tri-band (blue, green and red) emissions under a common excitation band—a property most desired by the scientist and technologists for generation of white light. XRD, TEM, HRTEM and SAED, studies of the system have confirmed the presence of the nanophases. Analysis of the emissions, their excitation dependence and excitation spectra, reveal that the strong blue emission comes mainly from PbO nanoclusters while green and red emissions should be related to ZnO nanobars. To identify the exact origins of the green and red emissions of the ZnO nanobars, EPR studies are made. ZnO-related defect centers namely interstitial Zn (Zn i ), singly charged oxygen vacancy ( V O ′ ) and Zn-substitutional Pb 3+ hole centers, are detected in the system. The results suggest that the green emission of ZnO, originates from its V O ′ defect centers, while the origin of red emission should be related to its doubly charged diamagnetic oxygen vacancy ( V O ″ ) centers.