Luminescence of II-VI semiconductor nanoparticles

Nanoparticle or an ultrafine particle is a small solid whose physical dimension lies between 1 to 100 nanometers. Nanotechnology is the coming revolution in molecular engineering, and therefore, it is curiosity-driven and promising area of technology. The field of nanoscience and nanotechnology is interdisciplinary in nature and being studied by physicists, chemists, material scientists, biologists, engineers, computer scientists, etc. Research in the field of nanoparticles has been triggered by the recent availability of revolutionary instruments and approaches that allow the investigation of material properties with a resolution close to the atomic level. Strongly connected to such technological advances are the pioneering studies that have revealed new physical properties of matter at a level intermediate between atomic/molecular and bulk. Quantum confinement effect modifies the electronic structure of nanoparticles when their sizes become comparable to that of their Bohr excitonic radius. When the particle radius falls below the excitonic Bohr radius, the band gap energy is widened, leading to a blue shift in the band gap  emission spectra, etc. On the other hand, the surface states play a more important role in the nanoparticles, due to their large surface-to-volume ratio with a decrease in particle size (surface effects). From the last few years, nanoparticles have been a common material for the development of new cutting-edge applications in communications, energy storage, sensing, data storage, optics, transmission, environmental protection, cosmetics, biology, and medicine due to their important optical, electrical, and magnetic properties.; Luminescence of II-VI semiconductor nanoparticles such as ZnS, CdS, ZnO, etc. has attracted a lot of attention in the last two decades due to their unique properties and potential applications in electronics, lighting industry, displays, DNA markers and other medical fields. In the present paper, the history, preparation, characterization, and optical absorption of nanoparticles are discussed. Then, the photoluminescence, electroluminescence, electrochemiluminescence, thermoluminescence, and elastico-mechanoluminescence of II-VI semiconductor nanoparticles are described. Finally, the challenges and applications of the luminescence of II-VI semiconductor nanoparticles are explored. It is mentioned that the great efforts made in the nanoparticle research during the last decade have gathered enormous knowledge related to nanoparticles and pointed out many important challenges. It is believed that the systematic investigation of a ‘synthesis-propertyapplication’ triangle for the nanoparticles will inspire more research activities to solve the current challenges and promote deep curiosity and intense interest in the study of inorganic semiconducting nanoparticles. © (2015) Trans Tech Publications, Switzerland.