The effect of synthetic parameters on the structure and luminescence properties of Zn1-xWxS quantum dots prepared via 2,2′-(Octadec-9-enylimino)bisethanol assisted microwave technique

Nanocrystalline Zn1-xWxS quantum dots have been successfully synthesized by 2,2′-(Octadec-9-enylimino)bisethanol assisted microwave synthesis using zinc acetylacetonate, tungsten acetate and thiourea. The as-grown Zn1-xWxS quantum dots have a highly crystalline cubic zinc blende structure and their lattice constants decreased with the increase of W ions into the ZnS cubic crystals. The as-synthesized Zn1-xWxS nanostructure QDs show luminescence emission intensity in the range 487-519 nm. The incorporation of the 7 mol% of W ions into the ZnS nanocrystals enhances the luminescence intensity and the quantum yield of the ZnS QDs by more than three times. The influence of microwave power and reaction time on the Zn0.93W0.07S QDs resulted in a strong blue shift of their luminescence peaks, thereby a decrease of the optical band gap. Therefore, the inclusion of W ions by 7 mol% into the ZnS nanocrystals at optimum P = 1200 W for 50 min via the developed technique promotes their luminescence properties 4 times and achieved quantum yield reached to 89%, while decreased the width of the PL peaks by 7 times rendering it a substantial advance in the development of unique optoelectronic devices such as laser diodes.