CdS_xSe_(1-x)/ZnS(核/壳)量子点的光谱截面及其掺杂光纤的传光特性

测量了不同组份比例x的CdS_xSe_(1-x)/ZnS(核/壳)量子点的吸收谱和发射谱,确定了量子点的吸收系数、吸收截面和发射截面.量子点吸收截面随粒径的增大而增大、随x的增大而减小.采用紫外固化胶,制备了掺杂浓度为0.1~5mg/mL的CdS_(0.4)Se_(0.6)/ZnS量子点光纤,测量了不同掺杂浓度量子点光纤中473nm泵浦功率的吸收衰减速率.吸收衰减速率和吸收截面弱关联于掺杂浓度.测量了光致荧光光谱强度随光纤长度和量子点浓度的变化.量子点光纤的光致荧光峰值强度随掺杂浓度和光纤长度变化而变化,且存在一个与最大峰值强度对应的饱和掺杂浓度和光纤长度.本文的实验结果有助于进一步构建新型的CdS_xSe_(1-x)/ZnS量子点增益型光电子器件.

Spectra Cross-sections of CdSxSe1-x/ZnS(core/shell)Quantum Dots and Photoluminescent Transmission of the Doped Fiber

The absorption coefficient,absorption and emission cross-sections of CdSxSe1-x/ZnS (core/shell) Quantum Dots (QDs) were determined by measuring absorption-emission spectra of the QDs with different composition ratio x.The absorption cross-section of QDs shows an increase with the increase of QD size,and shows a decrease with the x increase.In addition,CdS0.4 Se0.6/ZnS QDs doped fibers are prepared in a solid fiber core of ultraviolet gel in the doping concentration of 0.1 ～5 mg/mL.The absorption decay rate of 473 nm laser pumped into the QDs doped fiber are measured for different doping concentrations.There is evidence to show that the absorption-decay rate and the cross-section are weakly associated with the doping concentration,and the photoluminescence-peak intensity of the doped fiber varies with the fiber length and the doping concentration.There is a saturating doping concentration and desired fiber length corresponding to the maximum photoluminescent intensity.The experimental results provide a support for development of CdSx Se1-x/ZnS-QDs doped photoelectronic devices in the future.