本文選題：太赫茲頻段 + 單組分有機(jī)電光材料��； 參考：《電子科技大學(xué)》2016年博士論文

【摘要】：太赫茲技術(shù)在通信、雷達(dá)、安檢、射電天文、生物醫(yī)學(xué)等多個(gè)領(lǐng)域中的重要價(jià)值得到當(dāng)今科學(xué)界愈益增加的認(rèn)可。在這一新興科學(xué)技術(shù)領(lǐng)域,太赫茲輻射產(chǎn)生與檢測(cè)的能力與水平成為推動(dòng)太赫茲技術(shù)發(fā)展的關(guān)鍵。利用電光材料的光整流效應(yīng)產(chǎn)生太赫茲波、電光取樣技術(shù)檢測(cè)太赫茲波,是實(shí)現(xiàn)寬頻帶太赫茲波產(chǎn)生和檢測(cè)的常用方法之一。相比傳統(tǒng)的電光晶體材料,有機(jī)電光材料具有非線(xiàn)性光學(xué)系數(shù)大、響應(yīng)速度快、無(wú)聲子吸收帶隙等優(yōu)點(diǎn),并可根據(jù)需求進(jìn)行分子設(shè)計(jì)、修飾,易于提高材料性能,在太赫茲技術(shù)研究中得到了廣泛的關(guān)注。其中,高數(shù)密度單組分有機(jī)電光材料以其在電光性能方面的巨大潛力,近年來(lái)迅速成為電光材料領(lǐng)域關(guān)注的熱點(diǎn)。然而,為了使這類(lèi)材料能夠滿(mǎn)足太赫茲波產(chǎn)生與檢測(cè)的應(yīng)用要求,必須對(duì)包括電光活性、熱穩(wěn)定性和吸收損耗等材料關(guān)鍵性能進(jìn)行進(jìn)一步的綜合優(yōu)化。本文分析了電場(chǎng)極化引入發(fā)色團(tuán)取向過(guò)程中的電導(dǎo)機(jī)理,利用固態(tài)器件工程概念減少泄漏電流,提高了單組分有機(jī)電光材料的電光系數(shù);建立了單組分有機(jī)電光材料固有極化效率的評(píng)估標(biāo)準(zhǔn);系統(tǒng)地研究了單組分有機(jī)電光發(fā)色團(tuán)的結(jié)構(gòu)性質(zhì)關(guān)系,拓展了分子結(jié)構(gòu)對(duì)材料重要性能影響的認(rèn)知體系;探索研究了有機(jī)電光材料在太赫茲頻段折射率和吸收系數(shù)的快速表征方法。具體研究?jī)?nèi)容包括:1.苯并環(huán)丁烯阻擋層對(duì)極化過(guò)程中器件電導(dǎo)的抑制研究。單組分有機(jī)電光材料由于材料體系中有機(jī)電光發(fā)色團(tuán)數(shù)密度的增加,大大提高了電光性能,但也因此導(dǎo)致材料電導(dǎo)率的增加,其引發(fā)的泄漏電流在極化過(guò)程中限制發(fā)色團(tuán)分子的取向,成為實(shí)現(xiàn)大的電光系數(shù)所面臨的主要挑戰(zhàn)。本文通過(guò)對(duì)極化過(guò)程中泄漏電流本質(zhì)的理解和器件電導(dǎo)機(jī)理的分析,提出了在電極和電光材料層的交界面引入苯并環(huán)丁烯阻擋層,以阻止電荷注入。研究了阻擋層厚度對(duì)材料電光活性實(shí)現(xiàn)的影響,確定了阻擋層的最優(yōu)厚度區(qū)間。苯并環(huán)丁烯阻擋層的使用,有效降低了極化過(guò)程中的泄漏電流或器件電導(dǎo),保持有效極化電壓與外加電壓近似相等,顯著提高了高數(shù)密度單組分有機(jī)電光材料的電光系數(shù),所觀(guān)察到的最大電光系數(shù)是無(wú)阻擋層器件的2倍左右。其中,材料JRD1在極化電場(chǎng)大于85 Vμm-1的條件下,多次測(cè)試的電光系數(shù)超過(guò)之前報(bào)道的最大值400 pm V-1,并獲得了目前所報(bào)道的最大電光系數(shù)556 pm V-1。對(duì)比實(shí)驗(yàn)證明苯并環(huán)丁烯阻擋層對(duì)泄漏電流的抑制度比目前最常用的二氧化鈦?zhàn)钃鯇犹岣吡艘恢羶蓚�(gè)數(shù)量級(jí)。2.單組分有機(jī)電光材料極化效率的評(píng)估標(biāo)準(zhǔn)研究。單組分有機(jī)電光材料的高電導(dǎo)率問(wèn)題導(dǎo)致極化過(guò)程中電場(chǎng)強(qiáng)度的明顯降低,之前沿用的以外加電場(chǎng)強(qiáng)度作為極化電場(chǎng)強(qiáng)度的方法不能準(zhǔn)確計(jì)算此類(lèi)材料的極化效率。針對(duì)這個(gè)問(wèn)題,本文提出用極化過(guò)程中的平均電場(chǎng)強(qiáng)度作為極化電場(chǎng)值,通過(guò)電壓數(shù)據(jù)的分段擬合進(jìn)行計(jì)算。極化電場(chǎng)的這種修正算法充分考慮了極化過(guò)程中電場(chǎng)強(qiáng)度下降對(duì)電光系數(shù)的影響,使得從傳統(tǒng)器件的電光特性表征中就能準(zhǔn)確地評(píng)估單組分發(fā)色團(tuán)的實(shí)際電光性能。3.單組分有機(jī)電光發(fā)色團(tuán)的結(jié)構(gòu)性質(zhì)關(guān)系研究。單組分有機(jī)電光材料在應(yīng)用中有兩個(gè)潛在的不利條件:一是部分單組分有機(jī)電光發(fā)色團(tuán)易結(jié)晶,發(fā)生相位分離;二是這類(lèi)材料熱穩(wěn)定性(主要反映在玻璃化溫度)普遍偏低,降低工作裝置的可靠性和壽命。針對(duì)這個(gè)問(wèn)題,本文研究了有機(jī)電光發(fā)色團(tuán)的結(jié)構(gòu)性質(zhì)關(guān)系,通過(guò)對(duì)現(xiàn)有分子結(jié)構(gòu)的漸進(jìn)式改變,探索分子修飾對(duì)材料的最大電光系數(shù)、極化效率、玻璃化溫度和電導(dǎo)率等重要參數(shù)的影響。提出采用體積較大的叔丁基二苯基硅烷基團(tuán)對(duì)電子給體進(jìn)行修飾,以促進(jìn)非晶態(tài)薄膜的形成和極化效率的提高。在此基礎(chǔ)上,通過(guò)在電子橋上增加咔唑位置隔離基團(tuán),有效減小了分子間的偶極-偶極相互作用,制備出的材料極化效率約為3 nm2/V2,是目前報(bào)道的最高值,并且玻璃化溫度提高到100?C以上,比已見(jiàn)報(bào)道的同類(lèi)材料提高了20-40?C。4.超薄聚合物膜在太赫茲頻段的光學(xué)特性研究。有機(jī)電光材料在太赫茲波產(chǎn)生與檢測(cè)中的應(yīng)用需要解決相位匹配和吸收損耗問(wèn)題,因此在選擇材料時(shí),需要知道材料的折射率和吸收系數(shù)。傳統(tǒng)測(cè)試方法要求待測(cè)樣品厚度較大,存在與厚膜制作加工相關(guān)的一系列難題。本文探索性研究了利用衰減全反射技術(shù)在有機(jī)電光材料超薄薄膜上進(jìn)行折射率和吸收系數(shù)測(cè)試的方法,提出了應(yīng)用于該測(cè)試方法的新的器件結(jié)構(gòu),建立了一種與之相對(duì)應(yīng)的多層結(jié)構(gòu)分析模型,并利用Matlab程序?qū)崿F(xiàn)了對(duì)材料在太赫茲頻段折射率和吸收系數(shù)的分析。可行性驗(yàn)證實(shí)驗(yàn)顯示利用該方法測(cè)得的材料折射率和吸收系數(shù)與傳統(tǒng)方法的測(cè)試結(jié)果有良好的一致性。有機(jī)電光材料極化前后的折射率和吸收系數(shù)通過(guò)在幾個(gè)微米厚的薄膜上進(jìn)行測(cè)試即可獲得,實(shí)現(xiàn)了對(duì)材料光學(xué)特性的快速表征。
[Abstract]:The important value of terahertz technology in many fields, such as communication, radar, security, radio astronomy, biomedicine, and other fields, is gaining recognition. In this new field of science and technology, the ability and level of the generation and detection of terahertz radiation is the key to the development of terahertz technology. The terahertz wave should be produced by the terahertz wave. It is one of the common methods to realize the generation and detection of the broadband terahertz wave. Compared with the traditional electrooptic crystal material, the organic electro-optic material has the advantages of large nonlinear optical coefficient, fast response speed, no sound absorption band gap and so on, and can be designed and modified according to the demand. In the study of terahertz technology, the high density of single component organic electro-optic materials have become a hot spot in the field of electrooptic materials in recent years. However, in order to make this kind of materials meet the application of terahertz generation and detection It is required to further optimize the key properties of materials including electrooptic activity, thermal stability and absorption loss. This paper analyzes the conductivity mechanism of the electric field polarization introduced into the chromophore orientation process, reduces the leakage current by using the concept of solid-state device engineering and improves the electrooptic coefficient of the single component organic electrooptic material. The evaluation criteria for the intrinsic polarization efficiency of the single component organic electro-optic materials, the structural properties of the single component organic electrooptic chromophore, the cognitive system of the influence of the molecular structure on the material properties, and the rapid characterization of the emissivity and absorption coefficient of the organic electrooptic materials in the terahertz band are explored and studied. The study includes: the study of the inhibition of the conductance of the device in the polarization process of 1. benzo - butylene barrier. Single component organic electrooptic material increases the electrooptic performance greatly because of the increase of the number density of the organic light chromophore in the material system, but it also leads to the increase of the conductivity of the material, and the leakage current caused by the single component is limited in the polarization process. The orientation of the chromophore has become a major challenge for the realization of large electro-optical coefficients. By understanding the nature of the leakage current in the polarization process and the analysis of the mechanism of the device conductance, a benzo butylene barrier is introduced into the interface of the electrode and the electrooptic material layer to prevent the charge injection. The optimal thickness of the barrier layer is determined by the effect of the electrooptic activity. The use of the benzo butylene barrier effectively reduces the leakage current or the device conductance in the polarization process. The effective polarization voltage is approximately equal to the applied voltage, and the electro-optical coefficient of the high density single component organic electro-optic material is greatly improved. The maximum electro-optical coefficient is about 2 times that of the non barrier device. In the condition of the polarization electric field greater than 85 V M-1, the electrooptic coefficient of multiple tests is higher than the maximum value of the previously reported 400 PM V-1, and the maximum electro-optical coefficient of the present reported 556 PM V-1. has been reported to prove the leakage of the benzo butylene barrier over the experiment. The inhibition of current is higher than the most commonly used titanium dioxide barrier layer, which improves the evaluation standard of the polarization efficiency of one to two orders of magnitude.2. single component organic light materials. The high conductivity of the single component organic electro-optic material leads to the obvious decrease of the electric field intensity in the polarization process, and the electric field intensity as the polarization used before is used as the polarization. The method of electric field strength can not accurately calculate the polarization efficiency of this kind of material. In this paper, the average electric field intensity in the polarization process is used as the polarization field value and the piecewise fitting of the voltage data is calculated. This correction algorithm of the polarization field fully considers the electric field intensity decrease to the electro-optic system in the polarization process. The influence of the number makes it possible to accurately evaluate the actual electro-optic properties of single group distribution chromophores from the electrooptic characterization of traditional devices. The structural properties of.3. monocomponent organic light chromophores are studied. There are two potential adverse conditions in the application of single component organic electro-optic materials: one is that some monocomponent organic light chromophores are easy to knot. Crystal, phase separation, two is the thermal stability of this kind of material (mainly reflected at the glass temperature) is generally low, reducing the reliability and life of the working device. In this paper, the structure and property relationship of the organic electrooptic chromophore is studied. By the gradual change of the existing molecular structure, the maximum of the molecular modification to the material is explored. The effect of electrooptic coefficient, polarization efficiency, vitrification temperature and electrical conductivity, and so on. A large volume tert butyl two phenyl silane group was used to modify the electron donor in order to promote the formation of amorphous film and increase the polarization efficiency. On this basis, the effect of carbazole position isolation group was increased by increasing the position of carbazole. When the dipole dipole interaction between molecules is small, the polarization efficiency of the prepared material is about 3 nm2/V2, which is the highest value reported at present, and the glass temperature increases to more than 100? C. The optical properties of the 20-40? C.4. ultra-thin polymer film in the terahertz band are improved compared with the similar materials that have been reported. The organic electro-optic materials are in the terahertz wave. The application of generation and detection needs to solve the problem of phase matching and absorption loss, so it is necessary to know the refractive index and absorption coefficient of the material in the selection of materials. The traditional testing method requires that the thickness of the sample is large and there is a series of problems related to the fabrication and processing of thick film. The method of measuring the refractive index and absorption coefficient on the ultra-thin film of the organic electrooptic material is carried out. A new device structure applied to the test method is proposed. A multi-layer structure analysis model corresponding to it is established. The analysis of the refractive index and absorption coefficient of the material in the terahertz band is realized by the Matlab program. The experimental results show that the refractive index and absorption coefficient of the material obtained by this method are in good agreement with the test results of the traditional method. The refractive index and absorption coefficient of the organic electrooptic material before and after polarization can be obtained by testing on a few micron thick films, and the rapid characterization of the optical properties of the material is realized.

【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TN204

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 蔡禾;郭雪嬌;和挺;潘銳;熊偉;沈京玲;;太赫茲技術(shù)及其應(yīng)用研究進(jìn)展[J];中國(guó)光學(xué)與應(yīng)用光學(xué);2010年03期

相關(guān)博士學(xué)位論文 前1條

1 葉龍芳;基于光整流的太赫茲源與新型太赫茲導(dǎo)波結(jié)構(gòu)研究[D];電子科技大學(xué);2013年

，

本文編號(hào)：1858230