Ag纳米粒子增强CdS白光量子点器件的研制

在十八烯体系中合成Cd S量子点,用光诱导法制备银纳米粒子,并将两者复合,制备成4种复合样品,分析复合样品的荧光谱,在银纳米颗粒的表面等离子体共振峰分别对应于富含缺陷的硫化镉量子点的带边荧光峰和表面态荧光峰时,发生了带边荧光淬灭而表面态荧光增强的现象.结果表明,通过控制金属和量子点之间的距离,能够控制带边荧光辐射和缺陷带荧光辐射的比例,从而控制白光量子点的色温.采用395 nm紫光LED作为激发光源,将涂有荧光样品的玻片与激发光源组装成银纳米颗粒/量子点复合结构白光照明器件原型,银纳米粒子能够改变Cd S量子点样品发光颜色,荧光效应的增强程度随着量子点样品的厚度减小而加强.该研究为认识荧光物质和金属之间的相互作用提供了新途径,同时探讨了该器件在变色发光材料方向的应用前景.

Design for White Light Emitting CdS Quantum Dots Devices Enhanced by Silver Nanoparticles

Semiconductor quantum dots have unique optical properties due to the quantum size effect and surface effect. Investigations of SPR effects on light-emitting materials and devices have increased in this decade because of their promising applications in the enhancement of the luminescence efficiency，which has demonstrated a good application prospect in the materials science, biomedicine, optoelectronic devices and other fields. In our work, we prepare trap-rich CdS nanocrystals in the oleic system, and prepare Ag nanoparticles with light induced, then combine them into four kinds of composite samples to investigate the phenomenon that Ag nanoparticles always quench the band-edge emission and enhance the surface-state emission regardless of the SPR wavelength. Experimental results show that we can change the color of?quantum?dots fluorescence because the proportion of the band-edge emission and the surface-state emission can be controlled by the distance between CdS quantum dots and silver nanoparticles. Then a white light Emitting CdS quantum dots devices enhanced by silver nanoparticles is designed using nine 395 - nm wavelength violet-LEDs as excitation?light?source, CdS quantum dots/silver nanoparticles samples and tinfoil which can block the extra light. From the picture of real products, it shows that Ag nanoparticles can change the color of?quantum?dots fluorescence and enhance the photoluminescence which will become stronger when CdS quantum dots and Ag nanoparticles come closer. This investigation not only provides a new approach to study the interaction between fluorescent?material and metal, but also discuss the devices promising application in color-changed luminescent?materials.