【作者】 刘升建；

【导师】 G.C.Bazan； 曹镛；

【作者基本信息】 华南理工大学 ， 材料学， 2014， 博士

【摘要】 近三十来，聚合物发光二极管和聚合物太阳电池（PLEDs/PSCs），由于在通过旋涂或喷墨打印等湿法加工制备重量轻、大面积、柔性的光电转换器件方面具有广泛的应用前景，引起了学术界和工业界持续而广泛的关注。PLEDs/PSCs通常采用两个金属电极夹一层共轭聚合物的三明治结构，为了实现高效的PLEDs/PSCs，对共轭聚合物和金属电极的界面进行调控，使其形成欧姆接触至关重要。胺基功能化共轭聚合物（AFCPs）由于其具有优异的光电性能，能够采用正交、环保型溶剂加工，优异的阴极界面修饰能力，降低金属电极功函数等优势而展现了广泛的用途。基于AFCPs的阴极界面层，实现了高效、并以稳定金属为阴极的PLEDs/PSCs，其中实现了全溶液加工的、银胶为阴极的PLEDs；PSCs的能量转换效率达到9.2%，为文献报道单节PSCs的最高值之一。本论文的研究内容主要针对胺基功能化共轭有机/聚合物的主链结构和侧链结构进行优化和调控，使其多功能化，并成功应用于PLEDs/PSCs中。在第二章，为了克服溶液加工复杂的多层聚合物光电器件时存在的界面侵蚀、界面混溶等问题，提出了将可交联基团、具有阴极界面修饰能力的强极性官能团胺基链接于共轭聚合物侧链的设计思路，使其具多功能性。含可交联基团的AFCPs可通过环保型、正交溶剂加工成膜、且在加热或者光照条件下能相互反应形成不溶不熔的互穿网络聚合物膜，有利于溶液加工制备界面清晰的多层器件；此外，含可交联基团的AFCPs还兼具优异的阴极界面修饰功能。将其作为阴极界面层应用于PLEDs中，可以有效地促进高功函金属Al（或者ITO）阴极向发光层的电子注入，实现了高效稳定的PLEDs器件，正装PLEDs器件的最高流明效率达到了13.5cdA1；倒置PLEDs器件的最高流明效率达到了14.8cdA1。此外将其作为ITO阴极界面修饰层应用于倒置PSC（I-PSCs）中，I-PSCs器件的能量转换效率均大幅提高，最高能量转换效率超过9%，为文献报道单节聚合物太阳电池最高效率之一。在第三章，为了使AFCPs阴极界面层厚度在较宽的范围内，I-PSCs器件仍保持优异的性能，在传统AFCPs的主链引入半径较大的金属原子Hg，利用金属-金属的超分子相互作用，改善共轭聚合物的有序、规整排列，提高载流子的传输性能。主链含金属Hg原子的胺基功能化共轭聚合物PFEN-Hg具有正交溶剂加工特性、ITO阴极界面修饰能力、良好的载流子选择和传输性能、空穴阻挡性能、可见-近红外区域无吸收、较宽的光学带隙等优点，将PFEN-Hg作为ITO阴极界面层应用于I-PSCs中，器件的能量转换效率超过9%，为文献报道单节PSCs最高效率之一；且I-PSCs器件的光伏性能对PFEN-Hg界面层的厚度依赖性较小，在7-19nm范围内，器件的能量转换效率均超过8.6%。在第四章，首次设计并合成了结构确定、醇溶性的胺基功能化有机铂（II）配合物Pt-N，Pt-N兼具分子结构确定、易提纯、批次与批次差异小、器件重复性好、正交溶剂加工特性、阴极界面修饰能力、良好的载流子选择和传输性能、空穴阻挡性能、可见光-近红外区域吸收弱等优点，是一类优异的阴极界面修饰材料。Pt-N能帮助实现非常有效的电子收集，获得更好的器件性能，以Pt-N作为Al阴极的修饰层，采用高效的聚合物材料PTB7和PC71BM作为活性层，制备的PSCs能量转换效率可从参比器件的3.62%提高到8.89%。在第五章，为了系统研究侧链强极性官能团胺基含量的变化对共轭聚合物的电子注入性能、发光性能的影响，设计合成了三系列具有电子注入和优异发光性能的AFCPs，通过在主链掺杂生色团单元，实现了红、绿、蓝三基色发光。由于胺基与3,7-S,S-二氧-二苯并噻吩（FSO）的弱相互作用，形成激基复合物，光致发光光谱（PL）和电致发光光谱（EL）随着胺基含量增加而逐渐红移及变宽。所有发光聚合物均应用于纯Al为阴极的PLEDs器件中，蓝光聚合物当胺基含量从0%增加至1%，器件性能增加至3.28cdA1，胺基含量继续增加至5%和15%时，由于激基复合物的形成，器件性能反而下降。而绿光、红光聚合物PLEDs性能随着胺基比例增加而逐渐增加，发红、绿光PLEDs器件的最大流明效率分别为0.79和7.31cdA1。更多还原

【Abstract】 Polymer light-emitting diodes (PLEDs) and polymer solar cells (PSCs), have attractedconsiderable attention over the past decades due to their unique characteristics, such as lowcost, light weight, and possible flexibility and large-area coverage. Both PLEDs and PSCsusually adopt a basic architecture composed of a thin layer of organic semiconductingmaterial sandwiched between two electrodes. It is therefore important to control theproperties and Ohmic contact of the organic/electrode interface to maximize performance.Amino-functionalized conjugated polymers (AFCPs) have exhibited wide applications owingto their excellent optoelectronic properties, orthogonal solvent processibility, and outstandinginterfacial modification functions. Combined these advantages, high efficiency and stablePLEDs and PSCs based on AFCPs cathode interlayer have been realized. That directly leadedto the realization of the first high efficiency all-solution processed PLEDs based on Ag pastecathode. Single junction PSCs based on AFCPs cathode interlayer reached PCEs of up to9.2%, which is one of the highest PCEs for single junction PSCs.The studies demonstrated in this thesis are the development of novel multifunctionalamino-functionalized conjugated polymers by optimizing their backbones and side chains.The novel amino-functionalized conjugated polymers were successfully applied in polymerlight emitting diodes and polymer solar cells.In chapter2, a series of novel crosslinkable alcohol soluble conjugated polymers(PF6N-OX, PF3N-OX, PF6N-St) containing oxetane/styrene groups and aminoalkyl groupsin the side chains have been developed and used as highly efficient electroninjection/extraction and transporting material for PLEDs and PSCs. The unique solubility inpolar solvents and crosslinkable ability of the novel conjugated polymers render them a goodcandidate for solution processed multilayer and inverted PLEDs and PSCs.It was found that novel conjugated polymers (PF6N-OX, PF6N-St) can greatly enhancethe electron injection from high work-function metal cathode Al or ITO, due to its pendantamino groups, and so high efficiency and stable PLEDs have been realized. The resultingPLEDs and inverted PLEDs showed promising performance with a maximum luminance efficiency of13.53and14.8cd A-1, respectively.When the PF3N-OX was used as ITO cathode in inverted PSCs, the PSCs showedsignificantly improved performance, and the best PSCs reached PCEs of up to9%, which isone of the highest PCEs for single junction PSCs.In chapter3, a metal-based conjugated polymer PFEN-Hg with pendent amino groupswas synthesized and employed as an efficient interlayer to improve the electron transport andcollection property in high performance I-PSCs. This new polymer offers most of the desiredproperties one would consider for an efficient interface material including orthogonal solventprocessing ability, good film formation property, effective in workfunction modification ofthe ITO substrate, low optical absorption, good electron selectivity and good electrontransporting property. With these improved interfacial properties from the PFEN-Hginterlayer, I-PSCs showed very encouraging PCE of over9%, which is one of the bestreported performance for single-junction PSCs. An even more appealing feature offered bythe new interface material is the feasibility to achieve good device performance with a widerrange of film thickness, those property is good for large-area device processing.In chapter4, an amino-functionalized organoplatinum(II) complex called Pt-N wasdeveloped and utilized as an efficient Al cathode interlayer to improve the electrontransporting and collection in high performance PSCs. This new small molecule Pt-N offersmost of the desired properties one would consider for an efficient interface material includingwell-defined chemical structure, orthogonal solvent processing ability, good film formationproperty, low optical absorption, excellent electron selectivity, good hole-blocking ability. Byusing Pt-N as ETL underneath the Al cathode, the PCE values of the PSCs can be increasedfrom the initial3.62%to8.89%, benefiting from the dramatic enhancement in Voc, FF andslightly increase in Jsc. These results indicate that the amino-functionalized organoplatinum(II) complex would be a promising family of interfacial materials for highly efficient PSCs.In chapter5, a series of blue, green and red-emitting aminoalkyl functionalizedpolyfluorene derivatives containing FSO, BT and DTBT as chromophores, respectively weresynthesized. We found that the variation of molar ratio of aminoalkyl functional groups didnot significantly influence thermal stability, UV-vis absorption, photoluminescence as well as electrochemical properties of copolymers. The application of the resulted aminoalkylfunctionalized copolymers in polymer light emitting devices exhibited dual-functionincluding efficient light-emission and electron injection from Al cathode. The increase ofmolar ratio of aminoalkyl side groups leads to enhanced device performances for both greenand red-emitting copolymers, however, reduced performance for blue-emitting ones due toformation of excimer. Best device performance with the LEmaxof3.28,7.31and0.79cd A-1was achieved for devices based on blue, green and red-emitting copolymers, respectively wasachieved by using Al as cathode. The results indicated the great potential for the applicationusing this kind of aminoalkyl functionalized copolymers as efficient light emitting layer withhigh workfunction as cathode.更多还原