ZnSe纳米晶材料的超快吸收谱

通过改进的溶剂热方法,以KBH4作为还原剂,在三乙胺溶液介质中制备了ZnSe纳米晶材料.与ZnSe体材料相比,其纳米材料的稳态吸收边发生了蓝移,而且纳米颗粒的尺寸越小,蓝移量越大,这是由于随着尺度减少而引起的量子限制效应增强造成的.对在溶液中的ZnSe纳米颗粒的超快吸收谱的研究表明,当纳米颗粒的平均尺寸为75nm时,电子-声子散射时间为8.74ps;当平均尺寸为45nm时,散射时间为2.77ps.随着纳米颗粒尺寸的减小,载流子与颗粒表面的非弹性碰撞几率增加,从而使载流子-声子耦合的强度增强,导致载流子-声子散射时间缩短.

Ultrafast Absorption Spectra of Nanocrystal ZnSe Material

Using a modified solvothermal method in which potassium borohydride is employed as a reducing reagent,nanocrystal ZnSe materials are prepared in a triethylamine solvent.Compared to bulk ZnSe,nanocrystal ZnSe has a blue shift in its steady absorption edge.The degree of this blue shift increases with the decrease of nanocrystal particle size,as a result of quantum confinement effects.The ultrafast absorption spectra of ZnSe nanocrystals indicate that the electron-electron scattering time is 8.74ps and 2.77ps for the average nanocrystal size of 75 and 45nm,respectively.With the decrease of the size of nanocrystal,the probability of inelastic collision among carriers and nanocrystal surface increases,resulting in the enhancement of the carrier-phonon coupling strength and the shortening of the carrier-photon scattering time.