配位基對硒化鎘奈米粒子之光學性質研究

Ligand effect on optical properties of CdSe nanoparticles

林含芳

指導教授 ： 洪偉修

國立臺灣師範大學/理學院/化學系/碩士(2012年)

摘要

本論文主要藉由光譜之變化，剖析正烷基胺和正烷基硫醇與硒化鎘表面作用狀態。我們利用化學膠體法製備硒化鎘奈米粒子，紫外可見光光譜儀、螢光光譜儀、X光粉末繞射儀作光學性質及結晶性之鑑定。正烷基胺和正烷基硫醇為吸附物，去修飾硒化鎘表面。低濃度的正烷基胺能增強PL強度，而正烷基硫醇會導致PL強度焠滅。胺類使吸收和放射光譜都出現藍移，硫醇分子造成紅移發生。硒化鎘溶液加入正烷基胺有助於鈍化硒化鎘表面，它的頭端基能提供電子給金屬離子形成的懸空鍵，減少表面缺陷。正烷基硫醇與粒子作用，則會造成缺陷放光增加。對於配位基與奈米粒子作用情形，我們也建立Langmuir 模型求出吸附鍵結常數。以電子效應解釋其表面反應機制，正烷基胺有較強的供電子能力，使生成的反鍵結軌域提升至硒化鎘LUMO之上，消除了電子捕捉態。正烷基硫醇不傾向供給電子，無法消除捕捉態。

關鍵字

硒化鎘 ； 配位基

並列摘要

We studied influence on alkylamine and alkanethiol surface of CdSe through the variation of optical spectra. We Prepared CdSe nanoparticles were synthesized by using chemical colloidal method. The optical properties and crystallinity of CdSe are monitored by UV-Visible spectroscopy, Fluorescent spectrophotometer and X-ray powder diffractometer. Alkylamine and alkanethiol as adsorbates to modify surface of CdSe. Alkylamines enhance the CdSe photoluminescence(PL) and thiol quench CdSe PL. Amines induce a blue shift in both absorption and emission spectra and, while thiols cause a red shift. Alkylamine could effectively passivate surface of CdSe, its headgroup donate electrons to dangling bonds of metal ion(Cd2+), which led to decrease the surface defects. The results also presented here that show the deep trap emission enhancement from alkanethiol interaction with CdSe. We also use Langmuir model to estimate adsorption binding constants for the Ligand interaction with surface of nanoparticle. Mechanism for the electronic properties of surface. Alkylamine have stronger electron donating ability to form antibonding orbital above LUMO of CdSe, which means that eliminate the electron trap state but alkanethiol does not tend to donate electrons that which cannot eliminate the trap states.

並列關鍵字

CdSe ； Ligand

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