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[International Journal] Highly Luminescent Blue-emitting CdZnS/ZnS nanorods having Electric Field Induced Fluorescence Switching property
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Yonghee Lee , Somang Kim , Hyo Seok Kim , Jeong Bin Shin , Wonseok Choi , Hyunjin Cho , Kyungmok Kim , Taeyang Lee , Jinook Kim , In-byeong Kang , Kyung Cheol Choi , Yong-Hoon Kim and Duk Young Jeon
Journal of Materials Chemistry C, January , 2017
vol 5, no , pp 2098-2106
Abstract: We demonstrate for the first time highly luminescent blue-emitting CdZnS/ZnS wurtzite core/shell nanorods(NRs) that show electric-field-induced fluorescence switching properties. Uniform CdZnS NRs were rapidlysynthesized by injecting sulfur powder dissolved in 1-octadecene into a flask containing phosphonic acidligands, and subsequently ZnS shells were coated using reagents consisting of sulfur powder, zinc sulfateheptahydrate, and oleylamine. The growth of high-quality ZnS shells resulted in a dramatically increasedphotoluminescence (PL) quantum yield (QY) of B40% with a minimal red-shift of the blue PL peak, whichindicates that the combination of reagents successfully controlled a large number of defects appearing onthe surface of the NR cores. By pre-annealing CdZnS cores before growing ZnS shells, we could achieve anadditional increase in the maximum PL QY to 50%, decreases in both the full width at half maximum (FWHM)and the red-shift of the PL peak, and improved electric-field-induced fluorescence switching performance.Density functional theory calculations reveal that the effective relaxation of strain accumulating on the NRcore during shell growth is the key to our successful synthesis of blue-emitting NRs, and that the additionalimprovement in performance obtained through the pre-annealing process results from the elimination ofsulfur vacancies appearing at the surface of the NR core.