退火气压对于P3HT∶PCBM微观形貌及光伏性能的影响  

Effect of Annealing Pressure on P3HT∶PCBM Nanoscale Morphology and Photovoltaic Properties

作　　者：李畅[1] 薛唯[1] 章婷[1] 赵谡玲[2] 

机构地区：[1]北京理工大学光电学院,北京100081 [2]北京交通大学发光与光信息技术教育部重点实验室,北京100044

出　　处：《光谱学与光谱分析》2015年第1期19-23,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(10904002);教育部留学回国基金项目(20110432001);北京理工大学校优秀青年教师计划项目(2009Y0408)资助

摘　　要：通过精确设定不同的退火环境气压,实现对P3HT(Poly(3-hexylthiophene-2,5-diyl)与PCBM([6,6]-Phenyl C61butyric acid methyl ester)体系中聚噻吩结晶度以及共混相分离程度的控制,并在此基础上制备了结构为ITO/PEDOT∶PSS/P3HT∶PCBM/Al的正型光伏器件。在允许的压强设定范围内,器件各项性能参数均随退火环境压强的增大表现出先升高后下降的变化规律,并统一于气压设定为1 500mTorr时获得最大值。从活性层的紫外-可见(UV-Vis)吸收光谱中发现P3HT在510nm吸收峰以及550和600nm肩峰附近的吸收强度随退火气压升高而增大,在气压为1 500mTorr时达到最高,吸收强度的提升源于聚合物分子π—π堆叠的增加。原子力显微镜(AFM)进一步分析结果表明,高气压环境(>1 000mTorr)能够促进P3HT∶PCBM共混组分在退火过程中形成较大程度的相分离,而当环境压强合适时(1 500mTorr)适度的相分离利于聚合物形成良好有序结晶,从而能够提升活性层内部载流子传输能力,保证较高的短路电流与填充因子,制备的器件也因此表现出良好的光伏性能,光电转化效率达到3.56%。The considerable performance enhancement of P3HT-based solar cell after thermal annealing can be attributed to the thermodynamically driven partial crystallization and phase segregation of each component .In the present work ,thermal annea-ling was executed by delivering P3HT ∶PCBM blend films onto the preheated susceptor in a PECVD chamber filled with high purity nitrogen gas .The pressure of inner chamber could be set steadily and precisely in the range of 1 to 1 850 mTorr at 150 ℃ . It was found that the phase segregation scale of two components was tuned to a certain extent by varying the annealing pressure , whereas the polymer crystallinity was slightly affected .According to the pressure settings ,polymer solar cells （PSCs） were fab-ricated in the following structure ：ITO/PEDOT ∶ PSS/P3HT ∶ PCBM/Al .All of the device parameters exhibited the similar trend—an initial increase followed by a decrease ,and reached a peak at 1 500 mTorr with successive increase in annealing setting pressure .PSC annealed under 1 500 mTorr shows overall high performances with the power conversion efficiency up to 3.56% . The UV-Vis absorption spectra of annealed blend films shows that the vibronic absorption peaks （shoulders） at 510 ,550 and 600 nm became more pronounced under higher setting pressure ,which is attributed to better crystalline P3HT with increased π—πstacking of polymer molecules .The AFM results further suggest that high annealing pressure （〉1 000 mTorr） promoted the domain formations of P3HT or PCBM ;moreover ,a moderate phase segregation ,as a result of an appropriate annealing pressure （1 500 mTorr） ,facilitates polymer crystallization which ensures the high charge （hole） mobility and consequently increased＆amp;nbsp;short-circuit current and fill factor .

关 键 词：聚合物太阳能电池 退火压强 相分离 

分 类 号：O43[机械工程—光学工程] O469[理学—光学]