本文選題：紅熒烯　切入點：激子裂變　出處：《西南大學》2017年碩士論文　論文類型：學位論文

【摘要】：近些年,國內外越來越多的研究者開始對單重態(tài)激子分裂過程(簡稱激子裂變)進行研究,激子裂變已成為有機電子學中熱門的研究領域�，F階段,對激子裂變的研究主要在有機光伏器件上,能發(fā)生激子裂變的有機材料可作為一種新型的敏化劑,能夠大幅度提升有機光伏器件的量子效率。由于在單重態(tài)激子裂變過程中,有機材料吸收一個光子后被激發(fā),產生一個具有高能量的S1態(tài)激子,該S1態(tài)激子與一個處于基態(tài)的分子相互作用可轉換為一對具有低能量的T1態(tài)激子,這將提升有機光伏器件的量子效率。且T1態(tài)激子比S1態(tài)激子壽命要長,擴散范圍廣,有利于激子的拆分解離,這可進一步的提高光電轉換效率。目前,已有研究表明所制的有機薄膜器件中量子效率已經超過100%,如果能夠將能發(fā)生激子裂變的有機材料用在工業(yè)上,將會解決能源問題。但是,目前對激子裂變研究過程中還存在許多問題,對其過程研究不夠深入。本文中主要選了三個擬解決的問題進行研究。(1)有機薄膜材料的瞬態(tài)衰減曲線的擬合問題。在對激子裂變過程的研究中,實驗上研究者主要是通過對有機材料的瞬態(tài)衰減過程進行研究。在對光致發(fā)光瞬態(tài)衰減曲線擬合時,主要有兩種方法:一種用耦合速率方程組,但是擬合曲線與實驗曲線符合的不太好;另一種用方程式進行擬合,雖然擬合曲線與實驗曲線符合的很好,但是方程式的物理意義不明確,我們實驗組針對該問題對不同rubrene摻雜濃度的薄膜瞬態(tài)衰減過程進行研究。(2)不同摻雜濃度的有機薄膜器件激子裂變速率與分子間距之間的關系。實驗通過對不同rubrene摻雜濃度的薄膜進行研究,由于rubrene摻雜濃度不同可使分子間距不同,通過對薄膜的瞬態(tài)衰減過程進行研究,可得出激子裂變的速率,進而可得出激子裂變速率與分子間距之間的關系。(3)激子裂變的機制問題。目前,對于激子裂變機制主要有兩種不同的看法:一種看法認為其為“內轉換”模型;另一種認為其為“雙電子轉移”模型。本文通過對激子裂變過程進行分析,對激子裂變機制進行了驗證。在實驗中,通過雙源共蒸的方法將不同濃度的rubrene分子摻雜到主體材料中,制成有機薄膜器件。由于rubrene分子的摻雜濃度不同使得分子間距不同,結合實驗測量的薄膜器件在穩(wěn)態(tài)下的光致發(fā)光光譜及瞬態(tài)衰減曲線,對激子裂變過程進行分析。本文主要解決了上述的三個問題。各章節(jié)的主要內容如下:(1)第一章主要介紹了激子裂變的動力學過程,能發(fā)生激子裂變的幾種常見材料。同時,還說明了激子裂變的機制的兩種不同觀點,闡述了現階段激子裂變研究背景,需要解決的問題及發(fā)展前景。(2)第二章主要對有機薄膜器件的制備,樣品的光致發(fā)光光譜及瞬態(tài)衰減曲線的測量做了介紹。在對基片進行鍍膜時,我們采用分子束外延技術,在真空度約為10-5Pa條件下對樣品進行蒸鍍,并詳細闡述了實驗所用到的真空系統(tǒng)及監(jiān)控系統(tǒng)的原理及操作。同時,還對光致發(fā)光光譜和瞬態(tài)衰減曲線的測量儀器做了簡單的介紹。(3)第三章通過對Alq3:rubrene(x%)有機薄膜的光致發(fā)光及瞬態(tài)衰減過程進行測量,其中x取值從2%到50%。由薄膜器件的發(fā)光光譜圖分析得出了有機薄膜器件發(fā)光均來自rubrene分子。還得出一組既能夠使擬合曲線與實驗曲線符合的很好,物理意義明確的速率方程組。且經過分析薄膜的瞬態(tài)衰減曲線,得出了激子裂變速率與分子間距之間的關系為指數下降規(guī)律。同時,由擬合的瞬態(tài)衰減曲線對激子裂變電子轉移過程進行分析,驗證了激子裂變的機制為“雙電子轉移”模型,這對于明確激子裂變機制有重要的意義。
[Abstract]:In recent years, more researchers start to the singlet exciton splitting process (the exciton fission of exciton fission) has become a hot research field in organic electronics. At this stage, the research on exciton fission mainly in organic photovoltaic devices, organic materials can occur exciton fission can be used as a model the sensitizing agent, can greatly enhance the quantum efficiency of organic photovoltaic devices. Due to the singlet exciton fission process, organic material after absorption of a photon is excited to produce a high energy of S1 exciton, the S1 exciton and a ground state molecular interaction can be converted into a pair of with low energy T1 excitons, which will enhance the quantum efficiency of organic photovoltaic devices. And the T1 exciton exciton lifetime longer than S1, the diffusion range, there are split beneficial to the exciton dissociation. This can be further provided The high photoelectric conversion efficiency. At present, studies have shown that the organic thin film device made in quantum efficiency is more than 100%, organic materials can occur if the exciton fission in industry, will solve the energy problem. However, the exciton fission research process also exists a lot of problems, the research is not deep enough this paper mainly selected. Three problems to be solved are studied. (1) the fitting problem of transient organic thin film materials. The attenuation curve of exciton fission process, the researchers mainly through transient organic material degradation process were studied. The photoluminescence decay curve when fitting, there are two main ways: one using the coupled rate equations, but the fitting curve and the experimental curve with the not so good; another with a fitting equation, while the fitting curve and the experimental curve With the good, but the physical meaning of the equation is not clear, our experimental group to solve the problem of transient films of different doping concentration of rubrene decay was studied. (2) the relationship between organic thin film devices exciton fission rate and the distance between molecules of different doping concentration. The experimental research through the thin film of rubrene doped. Because of different doping concentration of rubrene can make the distance between molecules, by transient on the film attenuation process was studied. The rate of exciton fission, and obtained the relationship between exciton fission rate and molecular distance. (3) mechanism of exciton fission. At present, the main mechanism for exciton fission has two different views: one view is that the "conversion" model; another is that the "double electron transfer" model. Based on the exciton fission process analysis of shock Sub fission mechanism was verified. In the experiment, the method of using dual source co evaporation with different concentrations of rubrene molecules doped into the main material, made of organic thin film devices. Due to the different doping concentration of rubrene molecules and the molecular spacing, combined with experimental film device under steady state photoluminescence spectroscopy and transient decay the curve of exciton fission process were analyzed. This paper mainly solves the above three problems. The main contents of each chapter are as follows: (1) the first chapter mainly introduces the dynamic process of exciton fission, several common materials can occur exciton fission. At the same time, also illustrates the two different views of the mechanism of exciton fission. The present exciton fission research background, problems and future development needs to be solved. (2) the second chapter of the organic thin film device preparation, photoluminescence spectroscopy and transient decay Curve measurement is introduced. The coating on the substrate, we used molecular beam epitaxy in vacuum is about 10-5Pa of the samples under the conditions of evaporation, and expounds the principle and operation of the vacuum system used by the experiment and monitoring system. At the same time, the photoluminescence spectrum measuring instruments and the transient decay curves were briefly introduced. (3) the third chapter based on the Alq3:rubrene (x%) organic thin film photoluminescence and transient decay were measured, the x value from 2% to 50%. by the luminescence spectra analysis of thin film devices have been obtained from the light emitting machine thin film devices are drawn rubrene molecules. A group can make the fitting curve and the experimental curve is in good agreement with the rate equations, a clear physical meaning. And after the transient analysis of film decay curve, obtained the relationship between exciton fission rate and molecular distance for finger The law of number decline is also analyzed. Meanwhile, the electron transfer process of exciton fission is analyzed by fitting the transient decay curve. The mechanism of exciton fission is verified to be a "double electron transfer" model, which is of great significance for defining exciton fission mechanism.

【學位授予單位】：西南大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN304.5;TN305

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本文編號：1614937