Molecular conformation dependent emission behaviour (blue, red and white light emissions) of all-trans-β-carotene-ZnS quantum dot hybrid nanostructures

Abstract

A novel hybrid material consisting of all-trans-b-carotene and ZnS quantum dots (QDs) was prepared by two different controlled experiments and their photophysical properties were investigated in detail. Depending upon the preparation method, the b-carotene molecule had formed either an upright or wrapped conformation around the ZnS QDs and consequently the interaction between these two hybridizing systems was either charge transfer induced or electrostatic in type, respectively. Optical absorption, Raman and FTIR investigations have confirmed the two different conformations of the molecule around the ZnS QDs. Because of the two different conformations and the consequent interactions, different emission colours, such as blue and red wavelengths were obtained from these hybrids. We were also able to obtain white light emission by using cadmium doped ZnS QDs for the hybrid preparation.

Proposition and computational analysis of a kesterite/kesterite tandem solar cell with enhanced efficiency

“…It is known that J sc of the tandem cell is approximately equal to the minimum J sc of top and bottom cells, and it maximizes when J sc of top and bottom cells equals to each other. In tandem conguration, top and bottom cells absorb the shorter and longer wavelength 15,56,57 CZTSe (p) 15,36,51 CdS (n) 58,59 ZnS (n) 52,55,58,59 ZnO (n+) 53,54,[58][59][60] AZO (n++) 58,59,61 DC permittivity 7 7 10 9 9 9 Band gap (eV) 1.04 Â 10 À10 1.02 Â 10 À10 1.5 Â 10 À10 -- photons of the solar spectrum, respectively. To match the J sc of both cells, optical power absorption in two cells must be approximately equal.…”

Optical and Magnetic Properties of Ni Doped ZnS Diluted Magnetic Semiconductors Synthesized by Hydrothermal Method

“…Moreover, energy levels of vacancies are deeper than interstitial states [25]. The violet emission band at 424 nm is a sulfur vacancy ( S ) assisted one, caused by the transition from the sulfur vacancy state to the valence band edge state of ZnS nanorods [26]. The emission band centered at 505 nm is attributed to the transfer of trapped electrons on sulfur vacancies to interstitial sulfur states producing the green luminescence.…”

Boosting the efficiency of single junction kesterite solar cell using Ag mixed Cu2ZnSnS4 active layer

“…2 and Table 1 show the J-V characteristic and comparison between our simulation and experimental results, 8,15 respectively. The optical and basic electrical parameters as well as recombination parameters were taken from literature (optical; 20,21,[28][29][30] electrical 8,17,[19][20][21][22][23][24][31][32][33][34][35][36][37][38] (listed in Table 2)). In this respect, we have used minority carrier life time of CZTS 0.47 ns and 0.72 ns for matching with the experimental results of Shin et al 8 and Sun et al 15 respectively.…”