Green luminescence of ZnS and ZnS:Cu quantum dots embedded in zeolite matrix

Abstract

We report the synthesis of ZnS and ZnS:Cu (copper doped ZnS) quantum dots by chemical method at room temperature. In this technique ZnS and ZnS:Cu quantum dots are produced by simple chemical reactions where zeolite acts as matrix and plays the key role in controlling particle growth during synthesis. ZnS exhibits luminescence properties such as Zn2+ related emission. ZnS:Cu possesses Cu related emission, efficient low voltage electroluminescence, and super linear voltage-brightness electroluminescence characteristics. This study demonstrates the technological importance of semiconductor quantum dots prepared by low cost chemical route.

SnO2 quantum dots for nano light emitting devices

“…3) average particle size (crystallite size) is calculated by using Scherrer formula [2], D = 0.9λ W cos θ , λ is wave length of X-ray (0.1541 nm), W is FWHM (full width at half maxima), θ (theta) is the glancing angle and D is particle diameter (crystallite size). Considering all the peaks [3] (2θ in degree) in the X-ray diffractogram, the average crystallite (quantum dot) size has been calculated to be 9 nm. Further, by analyzing the X-ray diffractogram with the help of ICDD (International Center Diffraction Data) it has been revealed that SnO 2 quantum dots are "wurtzite" in structure.…”

“…To synthesize [3] SnO 2 quantum dots by quenching method, 4 gms of SnO 2 powder (99.99 % pure, E Merck) was calcined at ∼ 1000 • C for 10 hours and then quenched into 4 wt% aqueous solution of polyvinylpyrrolidone (PVP) matrix (99.9% pure, E Merck) kept at ice cold temperature followed by its moderate stirring (∼ 175 rpm). This solution contains SnO 2 quantum dots embedded in a polyvinylpyrrolidone matrix (chemical structure is shown in Fig.…”

“…The synthesis of semiconductor quantum dots and their different applications as various electronic and optoelectronic devices including different kinds of sensors, devices are among the top research areas at present [1][2][3][4][5][6]. Recently, many techniques [1][2][3][4] like molecular beam epitaxy (MBE), radio frequency sputtering (RF), liquid phase epitaxy (LPE), quenching etc.…”

“…have been adopted to synthesize semiconductor quantum dots. But due to its manifold advantages [3,6] viz. like simplicity and low cost, quenching method draws the interest of current researchers.…”

“…Recently, many techniques [1][2][3][4] like molecular beam epitaxy (MBE), radio frequency sputtering (RF), liquid phase epitaxy (LPE), quenching etc. have been adopted to synthesize semiconductor quantum dots.…”