有机—无机杂化钙钛矿材料的表面修饰及其器件组装

发布时间：2018-01-25 14:06

本文关键词： 有机无机杂化钙钛矿表面修饰界面工程电子转移传感器　出处：《山东大学》2017年博士论文　论文类型：学位论文

【摘要】：近年来,全球能源危机逐渐加深、环境污染不断加重,人们急需清洁、可再生的能源。太阳能作为全球最为丰富的清洁可再生能源,可以通过光电转换技术直接把光能转化成电能。在所有的光电转换技术中,有机-无机杂化钙钛矿(ABX3:A 为 CH3NH3+或 CH(NH2)2+,B 是 Pb2+,X 是 I-或 Br-或 Cl-)做为吸光层组装而成的太阳能电池的兴起与迅猛发展使之成为最有潜力的光伏材料。从2009年至今短短几年间,钙钛矿太阳能电池的光电转换效率已经从最初的3.8%增至22.1%,几乎可以与单晶硅太阳能电池(23.4%)相媲美,且组装工艺简单、成本低,有望成为已经工业化的硅基太阳能电池的最佳替补,被Science期刊评为2013年十大科技突破之一。虽然钙钛矿太阳能电池的光电转换效率较高,但器件的不稳定性成为其工业化亟待攻克的一个难题。因为钙钛矿材料对环境因素表现出较低的容忍度,比如湿气,水可以直接使CH3NH3PbI3分解为CH3NH3I和PbI2。本论文从界面工程的角度,选用具有特定功能傒二酰亚胺衍生物、苯胺类和具有不同疏水性的有机分子,对钙钛矿表面进行修饰,旨在提高钙钛矿材料的稳定性并探索钙钛矿材料在其他电子器件方面的应用,为组装高效、稳定的钙钛矿光电子器件提供理论基础。本论文的研究内容如下:第一章概述了钙钛矿材料的结构特点和性质,简述了纳米钙钛矿的制备并总结了钙钛矿太阳能电池、LED和激光器的工作原理以及界面工程在这些器件中所起的重要作用。第二章傒二酰亚胺衍生物作为一类具有良好光稳定性和光电性质的缺电子有机分子,常被用来作为有机太阳能电池中的电子受体。本章设计合成了对称的花二酰亚胺分子PDI-I,用具有光异构性质的4,4-二苯乙烯二羧酸(trans-SDBA,cis-SDBA)作为电子给体,来研究电子给体的异构化和电子受体的存在形式对跨界面电子转移的影响。紫外可见吸收光谱和稳态荧光光谱表明PDI-I和两种SDBA都能以1:1的比例通过离子作用形成稳定的配合物,但是与cis-SDBA所形成为配合物更稳定。电化学分析也显示cis-SDBA与PDI-I之间有更大的电子转移的驱动力,是更为合适的电子给体。然而淬灭实验表明trans-SDBA与PDI-I之间的电子转移效率更高。通过原子力显微镜和对比两种配合物在甲醇(PDI-I在甲醇中以单体形式存在,而在水中以聚集体形式存在)中的电子转移情况,cis-SDBA与PDI-I的相互作用太强以至于使PDI-I形成聚集体(PDI-I)n遭到破坏,由此可以看出,PDI-I的聚集程度和状态对跨界面的电子转移用着非常重要的影响。该研究结果为设计和调控傒二酰亚胺对钙钛矿进行表面修饰时的存在状态提供了指导。第三章选用傒二酰亚胺作为表面修饰剂,通过研究傒二酰亚胺与钙钛矿CH3NH3PbBr3之间的电子转移情况来探究钙钛矿受激发后的激子和表面缺陷情况。基于第二章的研究结果,我们设计合成了不易形成聚集体(减小探针分子本身的存在形式对电子转移的影响)且具有较强吸电子能力的傒二酰亚胺PDI。通过-NH3+的连接,将其成功修饰到CH3NH3PbBr3纳米颗粒表面。经过X-射线衍射分析,PDI修饰的CH3NH3PbBr3纳米粒子为立方晶相且具有良好的结晶性。稳态、瞬态荧光光谱和量子产率表明,钙钛矿的荧光几乎完全被PDI淬灭,这表明PDI分子能有效地提取钙钛矿中的光生电子,在PDI分子和钙钛矿纳米颗粒之间发生有效地跨界面电子转移。第四章选用灵活性和化学修饰性更强的一系列不同电子性质的苯胺分子作为修饰剂,即对位上有供电子的-OCH2CH3(-EtO)、H和吸电子的-OCF3的苯胺,探究芳香胺类有机分子作为钙钛矿表面修饰剂的可能性。通过调节苯胺盐与甲胺盐的比例,合成了一系列的CH3NH3PbBr3纳米粒子。通过核磁和热重分析,对位为H原子且碱性居中的苯胺An很容易修饰到钙钛矿CH3NH3PbBr3纳米粒子上;而对于碱性较强且具有供电子基团的EtO-An,只有当EtO-An与甲胺盐的比例大于1时,才能实现苯胺的修饰;而碱性最弱且具有吸电子基的OCF3-An,即使苯胺盐的比例再增加,也不能成功修饰钙钛矿。所以,影响钙钛矿表面修饰的因素除了修饰分子的碱性强弱,分子的空间位阻的影响是不可忽视的。此外,我们还研究了成功修饰后的钙钛矿纳米颗粒薄膜的电导,发现对位为供电子基团的EtOAn可以有效地增加钙钛矿的电导,该研究为调控钙钛矿的性质提供了新思路和指导。第五章我们利用界面电子转移成功拓展了钙钛矿材料在有毒N02气体识别方面的应用。我们旋涂四种不同浓度(20、25、30和35 ωt%)的前驱体溶液制备了一系列的MAPbBr3薄膜(SCFs),并用滴涂法制备了正辛胺封端的钙钛矿纳米颗粒薄膜(NPF)。实验结果表明,两种钙钛矿传感器均能对NO2气体实现可逆传感,但是其传感能力相差很大。对于SCFs传感器,依照35 wt%(0.1 ppm)30 wt%(0.15 ppm)25 wt%(0.38 ppm)= 20 wt%(0.38 ppm)的顺序,检测限依次增加,传感器传感反应能力按照30 wt%35 wt%25 wt%20 wt%的顺序依次降低。而对于NPF传感器,其检测限为0.1 ppm,传感反应能力略强于30 wt%SCF传感器,并且具有更好的稳定性。我们提出了钙钛矿SCF传感器对NO2可逆传感的机理:即氧化性的N02物理吸附在钙钛矿表面形成N02(ad),会发生从钙钛矿到N02(ad)的电子转移导致钙钛矿电子密度降低,电子电导下降。这是首次将有机铅钙钛矿用做化学气体传感器来识别有毒气体NO2。由于该传感器可以在室温下工作,具有很高的检测灵敏度,响应迅速,以及成本低、易组装等优点,因此具有很好的发展前景。第六章选用正辛胺、十二胺和十六胺三种不同碳链长度的脂肪胺盐,采用浸渍法对钙钛矿薄膜进行表面修饰。修饰后的脂肪链可以在钙钛表面形成一层疏水的分子层,防止水分子对钙钛矿薄膜的入侵,从而增加钙钛矿薄膜对水的稳定性。研究结果发现,十二胺对钙钛矿MAPbBr3薄膜的修饰效果最好,最佳的修饰时间为1.5 h,最佳的反应物浓度为20 mM。与未修饰的钙钛矿薄膜相比,表面钝化后薄膜的荧光寿命有所增加,薄膜的晶粒也略微增大,表面对水的接触角从38.1°提高到103.9°,由亲水性成功变为亲油性。在相对湿度为85%的条件下,薄膜的稳定性有了显著提高。第七章对论文的研究工作进行系统总结,包括论文的创新点和不足,并对研究工作进一步的展开提出展望。
[Abstract]:In recent years, the global energy crisis has deepened, environmental pollution is increasing, people need to clean, renewable energy. Solar energy is the most abundant renewable energy for the world, through the photoelectric conversion technology directly convert light into electrical energy. In all of the photoelectric conversion technology, organic-inorganic hybrid perovskite (ABX3:A CH3NH3+ or CH (NH2) 2+, B Pb2+, X is I- or Br- or Cl-) made solar cell into the light absorbing layer assembly and rapid development has become the most promising photovoltaic materials. Since 2009, just a few years, the photoelectric conversion efficiency of solar cell perovskite has from the initial 3.8% to 22.1%, almost with monocrystalline silicon solar battery (23.4%) comparable, and the assembly process is simple, low cost, is expected to become the best substitute of silicon-based solar cells has been industrialized, was named the Science Journal In 2013 ten major technological breakthroughs. Although higher photoelectric conversion efficiency of solar cell perovskite devices, but the instability has become a problem to be tackled in the industrialization. Because of environmental factors of perovskite materials exhibit a lower tolerance, such as moisture, water can be directly CH3NH3PbI3 decomposed into CH3NH3I and PbI2. from the interface the engineering angle, with specific function Xi two imide derivatives of aniline and with different hydrophobic organic molecules were modified on the surface to improve the stability of perovskite and perovskite materials and explore the application of perovskite materials in other electronic devices, to provide a theoretical basis for efficient assembly, perovskite stability. Research content of optoelectronic devices this thesis is as follows: the first chapter outlines the structure and properties of perovskite materials, nano perovskite preparation and the total The perovskite solar cells, an important role and working principle of LED laser and Interface Engineering played in these devices. The second chapter Xi two imide derivatives as a kind of good light stability and photoelectric properties of electron deficient organic molecules, is often used as a machine electron acceptor in solar cell. Two - the synthesis of PDI-I symmetric imine molecular design of this chapter, with two 4,4- styrene carboxylic acid having photoisomerization properties of two (trans-SDBA, cis-SDBA) as electron donor to study electron to form isomerization and electron acceptor of influence on cross interfacial electron transfer. UV Vis absorption spectra and steady-state fluorescence spectra showed that PDI-I and two SDBA can form stable complexes with the ratio of 1:1 by ion effect, but with cis-SDBA formed more stable complexes. The electrochemical analysis also showed that cis-SDBA and P There is a greater driving force for electron transfer between DI-I, is more suitable for the electron donor. However, quenching experiments show that the efficiency of electron transfer between trans-SDBA and PDI-I higher. By atomic force microscopy and comparison of two kinds of complexes in methanol (PDI-I in methanol, a monomer in the water to aggregates form) electron transfer in the interaction between cis-SDBA and PDI-I is too strong so that the formation of PDI-I aggregates (PDI-I) n is destroyed, it can be seen that the degree of aggregation and PDI-I of electron transfer across the interface with a very important influence. The research results provide guidance for the design and state of existence regulation two Xi imide modified the surface of the perovskite. The third chapter selects two Xi imide as surface modification agent, through the electronic transfer between two Xi imide and perovskite CH3NH3PbBr3 To explore the surface defects of perovskite exciton and after excitation. The results based on the second chapter, we designed and synthesized to form aggregates (reduced probe molecules form itself on electron transfer) and has strong electron withdrawing ability of two Xi imide PDI. through the -NH3+ connection, it will be successfully modified to the surface of CH3NH3PbBr3 nanoparticles. By X- ray diffraction analysis, CH3NH3PbBr3 nanoparticles modified by PDI is cubic phase and has good crystallinity. The steady state, suggesting that the transient fluorescence spectra and fluorescence quantum yield, perovskite PDI was almost completely quenched, suggesting that PDI molecules can effectively extract the perovskite in the photogenerated electrons effectively across the interfacial electron transfer between PDI molecules and perovskite nanoparticles. A series of different electronic properties of aniline and chemical modification of the fourth chapter with more flexibility As a molecular modifier, namely electron donor (-EtO), -OCH2CH3 - H and electron withdrawing -OCF3 aniline, as the possibility of perovskite surface modifier of aromatic amine organic molecules. By adjusting the proportion of aniline salt and methylamine, CH3NH3PbBr3 nanoparticles synthesized a series by NMR and thermogravimetric analysis. For An and H atoms on aniline in alkaline easily modified to perovskite CH3NH3PbBr3 nanoparticles; but for alkaline and has strong electron donating group EtO-An, only when the EtO-An and methylamine salt ratio is greater than 1, modified to achieve aniline; and alkaline and has the weakest electron withdrawing OCF3-An, even aniline salt the proportion increased again, can not successfully modified perovskite. So, the influence factors of surface modification of perovskite in addition to alkali modification of the molecule, the effect of molecular steric hindrance can not be ignored. In addition, we also studied the conductivity of perovskite nanoparticles films were successfully modified, found alignment as an electron donating group EtOAn can effectively increase the conductivity of the perovskite, provides new ideas and guidance for the study of perovskite regulation of the character. In the fifth chapter, we use the interface electron transfer successfully expanded the application of perovskite materials in toxic gas N02 recognition. We spin four different concentrations (20,25,30 and 35 Omega t%) a series of MAPbBr3 films prepared by the precursor solution system (SCFs), and preparation of octyl amine terminated perovskite nano particle film by drop coating method (NPF). The experimental results show that two kinds of perovskite type sensor can the NO2 gas sensor to realize reversible, but its sensing capabilities vary greatly. For the SCFs sensor, according to the 35 wt% (0.1 ppm) 30 wt% (0.15 ppm) 25 wt% (0.38 ppm) = 20 wt% (0.38 ppm) order, the detection limit were increase Plus, sensor response ability according to the 30 wt%35 wt%25 wt%20 wt% the order. But for the NPF sensor, the detection limit is 0.1 ppm, the sensing response ability is slightly better than the 30 wt%SCF sensor, and has better stability. We put forward the mechanism of perovskite SCF sensor on the NO2 reversible sensor: N02 oxidation of physics the formation of N02 on the adsorption surface of the perovskite (AD), occur from perovskite to N02 (AD) electron transfer to perovskite reduced electron density, electron conductivity decreased. This is the first organic lead calcium titanium mine as a chemical gas sensor to identify the toxic gas NO2. as the sensor can work at room temperature, with the detection sensitivity high response speed, and low cost, easy to assemble, so it has good prospects for development. The sixth chapter selects n-octylamine, twelve amines and sixteen amine three different carbon chain length of the fat Fatty amine salts by impregnation method for surface modification of Perovskite Thin Films. The modified aliphatic chain can form a layer of hydrophobic molecules in calcium titanium surface, prevent the intrusion of water molecules on the perovskite thin films, thereby increasing the stability of Perovskite Thin Films on water. The results of the study showed that the best modification effect of twelve amines on the perovskite MAPbBr3 thin films. The best modification time is 1.5 h, the best concentration was 20 mM. compared with the unmodified Perovskite Thin Films, surface passivation film fluorescence lifetime increased, the grain also increased slightly, the surface of the water contact angle from 38.1 degree to 103.9 degrees, from hydrophilic to hydrophobic success. When the relative humidity is 85%, the stability of the films has been significantly improved. The seventh chapter of this dissertation is summarized, including the innovations and shortcomings, and further research work A prospect is put forward.

【学位授予单位】：山东大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB306

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