I-HI-VI semiconductor nanocrystals

Semiconductor nanocrystals have received considerable attention due to their size-tunable spectroscopic properties and their applications in solar cells, light-emitting diodes, photodetector, biolabeling and nonlinear optical devices. Among various materials, nanocrystals of I- M -VI compounds (CuInS ₂, AgInS₂, CuInSe₂ and CuIn_xGa _1-xSe₂, etc. ) have been treated as not only alternative low toxic luminescent materials for bioimaging, and light-emitting diodes, but also suitable ink materials for solution process solar cells due to their unique properties such as tunable bandgaps, high absorption coefficient, large Stokes shifts. Recently, synthesis of I-M-VI nanocrystals has been extensively studied, resulting in various methods including precursor decomposition, hot injection and solvothermal methods. The developments of synthetic chemistry also provide high quality materials with controlled size, shape and compositions. This opens up the possibility to investigate their optical properties and explore their functional applications. The physical properties, especially their photoluminescence and electrochemical properties have been investigated to elucidate their size-dependent quantum confinement. Several specific characteristics were observed and demonstrated, providing important information for their applications. Recent works also reported several initial results of functionalization and devices applications, which are promising for future study. In this review, we provide an in-depth discussion of current progress and problems of colloidal I-M-VI semiconductor nanocrystals with an emphasis on the developing I-M-VI nanocrystals such as materials preparations, spectroscopic study and application explorations.