Improved electrochromism has been reported from a hybrid nanoheterostructure-based array designed using transition-metal oxides and conducting polymers. An improvement in color contrast, coloration efficiency, and operating voltage makes these hybrid core−shell-type nanostructures (NSs) suitable for power efficient and reversible electrochromic applications showing switching between transparent and opaque states rather than resulting in colored/ bleached switching. Nanopetals (NPs) of nickel oxide have been used as the backbone to grow nanohemispheres (NHs) of polyaniline onto a fluorine-doped tin oxide electrode using a two-step synthesis methodology consisting of a hydrothermal method, followed by an electrodeposition method. The coaxial NPs/NHs core−shell arrays exhibit a better electrochromic performance compared to their individual constituents. Devices fabricated using these hybrid NSs show power efficient optical switching between transparent and opaque with fast response and a good cycle life of approximately 1500. The coloration efficiency of the fabricated device has been calculated to be more than 145 cm 2 /C and an optical modulation of more than 45%.

A comparative analysis of two Raman line-shape functions has been carried out to validate the true representation of experimentally observed Raman scattering data for semiconducting nanomaterials. A modified form of already existing phonon confinement model incorporates two basic considerations, phonon momentum conservation and shift in zone centre phonon frequency. After incorporation of the above mentioned two factors, a rather symmetric Raman line-shape is generated which is in contrary to the usual asymmetric Raman line-shapes obtained from nanostructured semiconductor. By fitting an experimentally observed Raman scattering data from silicon nanostructures, prepared by metal induced etching, it can be established that the Raman line-shape obtained within the framework of phonon confinement model is a true representative Raman line-shape of sufficiently low dimensions semiconductors.