Book Description

In the past few years, it has been shown that inorganic-organic hybrid semiconductors are promising candidates for optoelectronics and clean energy applications. These materials have the advantage of combining the excellent electrical, optical, thermal and transport properties of inorganic components with the flexibility, processability and structural diversity of the organic components. A representative of such materials is the inorganic-organic hybrids based on II-VI semiconductors. We have developed a unique class of II-VI based hybrids composed of alternating layers of double atomic slabs of Zn2S2 and organic amine molecules. The Zn2S2 based double-layer hybrids emit bright white light and their internal quantum efficiencies have reached ~33-35%, very close to the performance level of the (YAG):Ce3+ yellow phosphors presently dominating the white light emitting diodes (WLED) market. We have demonstrated that their band-gap and photoluminescence properties, quantum yield and color quality can be systematically tuned by varying the doping level and composition of inorganic and organic components. Therefore, these white-light emitting hybrid semiconductors represent a new type of single-phased phosphors made of semiconductor bulk materials with great promise for use in WLEDs which are of intense interest for general illuminations. Furthermore, we have successfully synthesized a series of new hybrid materials containing one-dimensional chains or two-dimensional layers of V-VI motifs with organic spacers between the channels or the layers. Inserting organic amines in these crystal lattices reduces the thermal conductivity without any significant effect on the electrical conductivity, and thus, it may give rise to an increase in the figure of merit, a parameter that characterizes the effectiveness of thermoelectric devices. The ability to tune the optical, electrical, and thermal properties, coupled with their high fluorescence quantum yield, solution processability, low-temperature and cost-effective one-pot synthesis, precisely controllable stoichiometry and high yield, not only make these hybrid materials promising candidates for use in WLEDs, but also highly versatile semiconductors for a range of applications such as optoelectronics, energy generation, and conversion devices.