【作者】 陆运章；

【导师】 吕燕伍； 侯延冰；

【作者基本信息】 北京交通大学 ， 光学， 2013， 博士

【摘要】 本论文围绕影响体相异质结聚合物太阳能电池光伏性能的相关因素展开研究,主要内容分为三个部分：首先研究了热处理对聚3-己基噻吩：[6,6]-苯基c61丁酸甲酯(poly(3-hexylthiophene):[6,6]-phenyl C61butyric acid methyl ester, P3HT:PCBM)薄膜的形貌影响；接着对喹喔啉类共聚物材料poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-dyl-alt-thiophene-2,5-diyl](TQ)采用氟原子取替方法得到最高占据分子轨道(HOMO)能级更低的Poly[6-fluoro-2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl](FTQ), FTQ:PCBM作为活性层制备的器件开路电压更高；最后对基于poly[4,8-bis-alkyloxybenzo(1,2-b:4,5-b)dithiophene-2,6-diyl-alt-(alkyl thieno(3,4-b) thiophene-2-carboxylate)-2,6-diyl](PBDTTT-C)的聚合物光伏器件制备工艺和器件参数进行了优化,对器件稳定性进行了初步的探讨。1、利用退火处理对P3HT.PCBM共混膜形貌及其器件性能在不同温度下的影响进行研究。◇退火温度对P3HT:PCBM共混膜中PCBM团聚体的影响。实验结果表明,PC61BM和PC71BM团聚体的尺寸随退火温度的升高而逐渐增大,但是两种受体的聚集态明显不同,PC61BM聚集体呈树枝状,而PC71BM聚集体呈星状。◇A1电极对PCBM团聚体形成的影响。研究表明,先蒸镀A1电极再对P3HT:PCBM薄膜退火,A1层可避免微米量级的PCBM团聚体在薄膜表面出现。令热处理对P3HT的结晶态和薄膜的吸收强度的影响。退火温度的提高会增强薄膜中P3HT的吸收强度和结晶强度。◇热处理对P3HT:PCBM为功能层的光伏器件的影响。结果表明,当热处理温度接近P3HT玻璃化温度时,器件的性能得到了提高。在170℃下的30分钟热处理时,器件的性能最好。2、研究了氟取代的FTQ材料的吸收,薄膜形貌以及在光伏器件中的应用。◇氟取代TQ得到的FTQ材料比原材料TQ的HOMO能级更低,介电常数更高,从而相应器件的Voc有所增加。FTQ材料有1.70eV光学带隙,-5.51eV的HOMO能级和高达5.7×10-3cm2V-1S-1的空穴迁移率,是一种优良的光伏给体材料。FTQ:PC71BM共混膜在110℃退火后FTQ的吸收变化情况。退火后吸收峰发生红移,且吸收强度与红移量随时间增加而增加。◇优化了器件性能。以1：1的质量比制备的FTQ:PC71BM器件,在其功能层经历1分钟的短时间退火后,得到5.3%的转换效率。3、对于分别以聚(3,4-乙撑二氧噻吩)：聚(苯乙烯磺酸)(poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS)和氧化锌(ZnO)为修饰层的PBDTTT-C:PC71BM体系的传统型与倒置型两种器件,研究了影响器件性能的参数,通过优化参数得到高效率的光伏器件。探讨了两种器件在长期存放、光照和加热下性能的稳定性。令研究了溶剂与添加剂对以PBDTTT-C:PC71BM功能层的光伏器件性能的影响。比较了几种不同溶剂和添加剂制备的光伏器件的性能,结果显示以邻二氯苯(dichlorobenzene, DCB)为溶剂添加3%的二碘辛烷(1,8-diiodoctane, DIO)对,其器件性能达到最优,光电转换效率达到6.7%。◇探讨了传统结构和倒置结构器件在氮气环境下长期存放、模拟太阳光照和加热条件时性能的变化。发现传统正型器件比倒置型的效率衰减快。这是由于倒置型器件中电极修饰层为ZnO和氧化钼(MoO3)等稳定的无机化合物的保护作用,其器件效率衰减更慢。令以ZnO作为阴极修饰层,不仅有良好的电子传输能力,而且能提高器件的寿命与稳定性,倒置型器件是较理想的实用化的太阳能电池候选者。更多还原

【Abstract】 This work is focused on factors that influence the performance of the bulk-heterojunction polymer solar cells. The main contents of dissertation include three parts. Firstly, temperature-dependent morphology alteration of the P3HT:PCBM blend solar cells during annealing processes were investigated. Secondly, in order to obtain a lower HOMO energy level donor material, the copolymer material FTQ was synthesized by using the fluorine atom to substitute the hydrogen atom in the TQ, which effectively improved the open circuit voltage of the FTQ:PCBM devices. Finally, the optimised PBDTTT-C:PCBM devices with high photovoltaic performance were fabricated. Compared to the conventional stucture devices, the inverted structure devices have better illumination and thermal stability, where the ZnO and MoO3as buffer layers.1The effect of thermal treatment on the morphology of P3HT:PCBM blend film and the performance of device based on P3HT:PCBM was studied.The influence of the thermal treatment processing on PCBM aggregations in P3HT:PCBM blend film were discussed. The results showed the size of PC61BM and PC71BM aggregations gradually enhance with the increasing temperature of thermal treatment, however the shape of two aggregations are significantly different, where the PC61BM aggregation with dendritic pattern, and the PC71BM aggregation with stellate pattern.The impact of Al electrode on the formation of PCBM aggregations was discussed. A1layer can limit the formation of microns PCBM aggregations in the active layer when A1electrode vapor-deposited before thermal annealing, which benefits to the dissociation of excitons and the transport of carriers.The influence of the thermal treatment on the P3HT crystalline state and the optical absorption of the film were discussed. With the temperature thermal treatment increased, the absorption and crystallinity of the P3HT blend film are enhance. Meanwhile the absorption peak shifts to long wavelength slightly.The impact of the annealing on the performance of P3HT:PCBM devices were studied. When the annealing temperature rised from130to170°C, the device performance has also been improved. The max efficiency of the was achieved, when the devices were annealed at170°C for30minutes. 2The fluorine-substituted TQ material, FTQ, were characterized, and the photovoltaic performance of the devices based on TQ and FTQ were studied and compared.The FTQ with optical band gap of1.70eV, the HOMO level of-5.51eV and the hole mobility up to5.7×10-3cmV-S-1. Compared to TQ, FTQ, fluorine-substituted by TQ, showed lower HOMO level and higher relative dielectric constant, which decides that the devices based on FTQ have higher Voc.The changes in the absorption of FTQ:PC71BM blend film during thermal treated at110°C was investigated. After thermal annealing, the obvious redshift of absorption peak of FTQ happens and the absorption increases with the increasing time.The device performance was optimized. The efficiency of5.3%was obtained for FTQ:PC71BM device with a mass ratio of1:1in its active layer, processing with a short time of1minute thermal annealing at110°C.3To study the key factor to affect the device performance, two kinds of device based on PBDTTT-C:PC71BM were fabricated, where the PEDOT:PSS and the ZnO were used as modified layers in conventional and inverted structure devices, respectively. By optimizing the parameters, the high efficiency device was obtained. The stability of the two kinds of devices in the long-term storage, illumination and thermal conditions were investigated.The effect of solvents and additives on the performance of the device were investigated. While DCB as the solvent to add3%DIO, the efficiency up to6.7%was achieved.In a nitrogen atmosphere, the aging of the devices with two structures were investigated in different conditions:the long-term storage, the illumination of solar simulator, and high temperature. The results show that conventional-type device decay faster than the inverted-type device. Due to using stable inorganic compound such as the ZnO and the MoO3as modified layer, the efficiency of the inverted-type device decays more slowly.ZnO, as a cathode modified layer, not only has good electron transport mobility, but also improves the lifetime and stability of the devices. The inverted-type device is an ideal practical solar cell candidate.更多还原