Investigation of the Role of the Acceptor Molecule in Bulk Heterojunction Photovoltaic Cells Using Impedance Spectroscopy
详细信息 查看全文
- 作者：Riccardo Casalini ; Sai Wing Tsang ; James J. Deininger ; Frank A. Arroyave ; John R. Reynolds ; Franky So
- 刊名：The Journal of Physical Chemistry C
- 出版年：2013
- 出版时间：July 11, 2013
- 年：2013
- 卷：117
- 期：27
- 页码：13798-13804
- 全文大小：396K
- 年卷期：v.117,no.27(July 11, 2013)
- ISSN：1932-7455
文摘
An investigation of the recombination kinetics and the density of states distribution in bulk heterojunction organic photovoltaic cells was undertaken using impedance spectroscopy measurements under varying levels of illuminations. Three organic polymer solar cells were investigated which differed only by the p-type polymer used in the active layers while the device architecture and acceptor molecule (PC70BM) were kept the same. We found that the density of states profiles for the three cells are similar and can be superimposed by a horizontal shift due to a difference between the polymers鈥?HOMO and the PC70BM鈥檚 LUMO levels. The recombination mechanisms for the three cells showed the same behavior, suggesting an important role of the acceptor in this process; however, large differences in the absolute value of carrier lifetime 蟿eff related to the choice of the polymer are evident, indicating that the recombination kinetics depends on a combination of the properties of both materials and the morphology of their blend.