Real-Time Investigation of Crystallization and Phase-Segregation Dynamics in P3HT:PCBM Solar Cells During Thermal Annealing
Real-Time Investigation of Crystallization and Phase-Segregation Dynamics in P3HT:PCBM Solar Cells During Thermal Annealing
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DOI：
10.1002/adfm.201002076
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发表时间：
2011-05-10
影响因子：
19
通讯作者：
Macdonald, J. Emyr
中科院分区：
文献类型：
--
作者：
Agostinelli, Tiziano;Lilliu, Samuele;Macdonald, J. Emyr
热退火过程中的结晶和相分离导致聚（3-己基噻吩）（P3HT）：[6,6]-苯基c61 -丁酸甲酯（PCBM）块状异质结太阳能电池的功率转换效率提高。了解结晶和相偏析发生的长度和时间尺度对于改善纳米形貌的控制是重要的。在热退火过程中，利用掠入射x射线衍射实时监测结晶过程。此外，利用椭偏仪监测了薄膜密度的变化，利用场效应晶体管监测了载流子迁移率的演变。从这些测量与器件性能作为退火时间的函数的测量相结合，得出结论，微观结构的演变涉及两个重要的时间窗：i)第一个时间窗约为5分钟，其中聚合物的结晶与光电流的主要增加有关；ii)约30分钟的第二个窗口，在此期间PCBM继续聚集，并伴随着填充因子的增加。
Crystallization and phase segregation during thermal annealing lead to the increase of power-conversion efficiency in poly(3-hexylthiophene) (P3HT):[6,6]-phenyl C61-butyric acid methyl ester (PCBM) bulk-heterojunction solar cells. An understanding of the length and time scale on which crystallization and phase segregation occur is important to improve control of the nanomorphology. Crystallization is monitored by means of grazing incidence X-ray diffraction in real time during thermal annealing. Furthermore, the change in film density is monitored by means of ellipsometry and the evolution of carrier mobilities by means of field effect transistors, both during annealing. From the combination of such measurements with those of device performance as a function of annealing time, it is concluded that the evolution of microstructure involves two important time windows: i) A first one of about 5 minutes duration wherein crystallization of the polymer correlates with a major increase of photocurrent; ii) a second window of about 30 minutes during which the aggregation of PCBM continues, accompanied by an increase in the fill factor.