Nanoscale structural and electronic evolution for increased efficiency in polymer solar cells monitored by electric scanning probe microscopy

作     者：Denghua Li Han Yan Chao Li Yanlian Yang Zhixiang Wei Chen Wang 

作者机构：CAS Key Laboratory of Standardization and Measurement for Nanotechnology National Center for Nanoscience and Technology 

出 版 物：《Chinese Science Bulletin》 (科学通报(英文版))

年 卷 期：2014年第59卷第4期

页      面：360-368页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：supported by the National Basic Research Program of China(2011CB932800 and 2013CB934200) Sino-British Collaboration Program(2010DFA64680) National Natural Science Foundation of China(20973043) Chinese Academy of Sciences(KGCX2-YW-375-3) 

主　　题：塑料太阳能电池 扫描探针显微镜 纳米结构 进化 电子 聚合物 表面光电压 监测 

摘      要：Control of blend morphology at multi-scale is critical for optimizing the power conversion efficiency(PCE)of plastic solar cells.To better understand the physics of photoactive layer in the organic photovoltaic devices,it is necessary to gain understanding of morphology and the corresponding electronic property.Herein we report the correlation between nanoscale structural,electric properties of bulk heterojunction(BHJ)solar cells and the annealing-induced PCE change.We demonstrate that the PCE of BHJ solar cells are dramatically improved(from1.3%to 4.6%)by thermal annealing,which results from P3HT crystalline stacking and the PCBM aggregation for interpenetrated network.The similar trend for annealinginduced photovoltage and PCE evolution present as an initial increase followed by a decrease with the annealing time and temperature.The surface roughness increase slowly and then abruptly after the same inflection points observed for photovoltage and PCE.The phase images in electric force microscopy indicate the optimized P3HT and PCBM crystallization for interpenetrating network formation considering the spectroscopic results as well.From the correlation between surface photovoltage,blend morphology,and PCE,we propose a model to illustrate the film structure and its evolution under different annealing conditions.This work would benefit the better design and optimization of the morphology and local electric properties of solar cell active layers for improved PCE.