- 學位論文
介孔分子篩MCM-48之時間鑑別光激螢光研究
Studies of time-resolved photoluminescence in mesoporous MCM-48
摘要
本文利用時間鑑別光激螢光研究MCM-48的發光機制。利用脈衝雷射(波長396 nm)為激發光源，發現其光激螢光隨時間衰減的趨勢為一非單一指數函數或雙指數的衰減，光激螢光隨時間衰減的圖形可用延伸型指數函數擬合。MCM-48光激螢光強度在溫度50 K至300 K過程中，強度有明顯的衰減，這和非輻射發光過程與載子藉由聲子所產生的活化過程有很大的關聯性。由載子生命期與螢光能量的分析中，可得知MCM-48的光激螢光具有載子侷域化的現象。我們根據載子侷限效應和聲子有關的非輻射發光過程提出了一個模型，同時說明了隨溫度變化之載子生命期和隨溫度變化之光激螢光強度等現象。
並列摘要
Time-resolved photoluminescence was used to investigate the luminescence mechanism in MCM-48. The excitation source was a solid-state laser with the wavelength of 396 nm. The PL lifetime of MCM-48 is not a single exponential or bi-exponential profile, but follows a stretched exponential function. In the temperature range from 50 to 300 K, the PL intensity decreases, which is suggested to be an indication of the phonon-assisted nonradiative process. From the analysis of the energy-dependent carrier lifetime, we observed the carrier localization of the PL. The temperature dependence of PL lifetime and PL intensity has been explained using a model considering the carrier localization of radiative recombination and the phonon-assisted nonradiative recombination.