By adopting a facile, environmentally benign, solution phase method under ambient conditions, we have successfully synthesized all-inorganic cesium lead halide perovskite 1D rods.
Nanocrystalline, p-type semiconducting, transparent CuAlO2 thin films were deposited by direct current sputtering of a prefabricated polycrystalline CuAlO2 target, with deposition time as a variable parameter. Transmission electron micrographs reveal the formation of CuAlO2 nanoparticles. For the films deposited in 3, 9, and 15min, the average particle sizes are determined to be around 10, 20, and 30nm, respectively. The interplaner spacings calculated from selected area electron-diffraction patterns obtained from transmission electron microscopy confirmed the proper phase formation of the material. X-ray diffraction measurements of the films deposited for 15 and 45min show some diffraction peaks, which depict the rhombohedral crystal structure of the material. The band-gap values obtained from the optical transmission and reflection data, for the films deposited in 3 and 9min, are 3.94 and 3.84eV, respectively, whereas for those films deposited in 15 and 45min, the band-gap values lie in the range of 3.72–3.60eV. These values are quite larger than that of bulk material, which is around 3.34eV. The particle sizes in these cases are, respectively, 30 and 60nm. It is well known that quantum confinement in semiconductor nanocrystals leads to the band-gap widening with respect to the bulk material. In this report we have observed an increase in the band gap of the nanostructured p-type semiconducting CuAlO2 thin film with the decrease in the particle size. Room-temperature photoluminescence measurements of this material are reported, which showed an ultraviolet near-band-edge emission around 3.60eV, which originates from the generation and recombination of electron-hole pairs, namely, excitons. From the semiquantitative arguments it is supposed that the natural layered structure of delafossite CuAlO2 is responsible for the stability of the excitons. Also a blueshift of the emission peaks is observed with a decrease in the particle size, which may be described as another experimental indication of the quantum confinement effect within our nanocrystalline CuAlO2 thin films. The p-type nature of the films was established by hot-probe and thermopower measurements.
Nanocrystalline undoped and Mn doped zinc sulphide (ZnS) thin films were synthesized by
a wet chemical route without using any capping agent. The x-ray diffraction pattern
showed the typical interplanar spacings corresponding to the cubic phase of ZnS.
Transmission electron microscopy (TEM) studies confirmed the nanocrystalline nature with
an average particle size nm. Compositional information was obtained from the energy dispersive x-ray studies. A
UV–visible optical spectroscopy study was carried out to determine the bandgap of the
nanocrystalline ZnS and it showed a blue-shift with respect to the bulk value.
Variation of bandgap energies with annealing temperature was also studied in
detail. A photoluminescence (PL) study of the ZnS and ZnS:Mn films at room
temperature (300 K) indicated a strong luminescence band at energy 2.07 eV.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.