A variety of nanostructured materials are now available with precise control of their energy band structures due to quantum-confinement of electrons caused by changing morphologies and constituent materials due to recent developments of nanotechnology. These band-structure-engineered nanomaterials, possessing significantly modified physical and chemical properties against their bulk counterparts, in turn, are offering low-cost options of realizing altogether newer classes of electronic/opto-electronic devices by involving nanocrystals in place of atomic and molecular species as building blocks. The progress made in fabricating a number of useful devices such as light emitting diodes, photodetectors, solar cells, laser diodes, field effect transistors, memory and thermoelectric devices based on nanocrystals is reviewed here to assess their advantages in terms of the optimal use of the electronic wave functions of the modified discrete and extended electron energy states involved therein. Current status and future trend in preparing solution-grown nanocrystals for producing such devices are discussed here by citing the latest experimental results. The trend of realizing these devices in the last few years shows their imminent industrial applications in near future. The impact of this kind of device technology development is expected to complement the microelectronics technology to have more profound impact on human society.
