【摘要】 以氯化钠为助熔剂,在较低温度(约700℃)下的空气气氛中煅烧硫化锌合成了ZnO绿色荧光粉.测定了不同煅烧温度下合成荧光粉的激发光谱和发射光谱,以及硫、氯元素含量.结果表明,合成荧光粉的主晶相为六方纤锌矿结构的ZnO,并有少量残存的ZnS相存在.在350nm波长光激发下,该荧光粉的发射光谱只有505～510nm绿色峰,无380nm激子发射.根据给体-受体机制,该发射是源于光生电子从局域缺陷中心(给体)向陷阱空穴(受体)的跃迁.煅烧过程中氯化钠的存在大大提高了产物的荧光发射强度,这归因于荧光粉中硫、氯的共掺杂对缺陷VO+和Zn(1-z)+形成的直接贡献.该荧光粉能与近紫外发光二极管相匹配,有望应用于白光二极管.更多还原

【Abstract】 ZnO phosphors with highly efficient green luminescent emission have been prepared by calcining ZnS in air atmosphere at different temperatures with NaCl as flux. The photoluminescence spectra and the contents of S and Cl of ZnO phosphor were determined. The results showed that the phosphors were composed of ZnO with hexagonal wurtzite structure, however, few of cubic ZnS still remained. Under excitation of 350 nm radiation, the phosphors emit strong green light at around 510 nm with no band to band exciton emission around at 380 nm. According to accepterdonor transition mechanism, this green emission band can be ascribed to a transition of photogenerated electrons from the localized defect centers (donor) to deeply trapped holes (acceptor) in the bandgap. The highly enhacement of NaCl for the luminescent emission of ZnO is attributed to the co-doping of S and Cl, which results in the formation of defects both VO+ and Zn(1z)+. The phosphor prepared at 700℃ showed the highest luminescent intensity under 380 nm irradiation, and could be used in white light-emitting diodes (LEDs).更多还原