Influence of Side Chains on Geminate and Bimolecular Recombination in Organic Solar Cells

被引:33
作者
Massip, Sylvain [1 ]
Oberhumer, Philipp M. [1 ]
Tu, Guoli [2 ]
Albert-Seifried, Sebastian [1 ]
Huck, Wilhelm T. S. [2 ]
Friend, Richard H. [1 ]
Greenham, Neil C. [1 ]
机构
[1] Univ Cambridge, Cavendish Lab, Dept Phys, Cambridge CB3 0HE, England
[2] Univ Cambridge, Chem Lab, Melville Lab Polymer Synth, Cambridge CB2 1EW, England
关键词
DONOR-ACCEPTOR POLYMERS; CHARGE RECOMBINATION; PHOTOVOLTAIC PROPERTIES; POLYFLUORENE COPOLYMER; ELECTRON-TRANSFER; DEVICE PHYSICS; PERFORMANCE; STATE; FILMS; GENERATION;
D O I
10.1021/jp2070584
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The effects of the side chains on the loss processes in three polymer:PC[61]BM organic blends are studied by comparing transient absorption spectroscopy and solar cell measurements. It is shown that, after efficient photoinduced charge transfer, charge pairs are the only significant species present in the blend and that their recombination can be followed by monitoring the PIA kinetics. Charges are found to decay following two regimes. The subnanosecond decay of the charge signal, responsible for the losses of 55-75% of the charges, is well described by an Onsager-Braun geminate recombination model. The rates are found to be strongly affected by the presence and position of side chains, We attribute these changes to a better aggregation of the side-chain-less polymer that provides a better delocalization of the holes and a better mobility. At longer times (after about 10 ns) the charges undergo bimolecular recombination. By modeling the time and intensity dependence of this process, we measure the rate constant and find that it is similar for the three systems and slightly lower than the theoretical Langevin rate. By comparing these spectroscopic results with the light-intensity and bias dependence of the photocurrent, we conclude that bimolecular recombination does not play an important role under solar intensity. Geminate recombination is the main loss mechanism and explains the difference between all the devices, their strong bias dependence, and their generally low performance.
引用
收藏
页码:25046 / 25055
页数:10
相关论文
共 64 条
[1]   Impact of the Alkyl Side Chains on the Optoelectronic Properties of a Series of Photovoltaic Low-Band-Gap Copolymers [J].
Biniek, Laure ;
Fall, Sadiara ;
Chochos, Christos L. ;
Anokhin, Denis V. ;
Ivanov, Dimitri A. ;
Leclerc, Nicolas ;
Leveque, Patrick ;
Heiser, Thomas .
MACROMOLECULES, 2010, 43 (23) :9779-9786
[2]   Device physics of polymer:fullerene bulk heterojunction solar cells [J].
Blom, Paul W. M. ;
Mihailetchi, Valentin D. ;
Koster, L. Jan Anton ;
Markov, Denis E. .
ADVANCED MATERIALS, 2007, 19 (12) :1551-1566
[3]   Toward a rational design of poly(2,7-carbazole) derivatives for solar cells [J].
Blouin, Nicolas ;
Michaud, Alexandre ;
Gendron, David ;
Wakim, Salem ;
Blair, Emily ;
Neagu-Plesu, Rodica ;
Belletete, Michel ;
Durocher, Gilles ;
Tao, Ye ;
Leclerc, Mario .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2008, 130 (02) :732-742
[4]   A low-bandgap poly(2,7-carbazole) derivative for use in high-performance solar cells [J].
Blouin, Nicolas ;
Michaud, Alexandre ;
Leclerc, Mario .
ADVANCED MATERIALS, 2007, 19 (17) :2295-+
[5]   Low-Temperature Control of Nanoscale Morphology for High Performance Polymer Photovoltaics [J].
Campbell, Andrew R. ;
Hodgkiss, Justin M. ;
Westenhoff, Sebastian ;
Howard, Ian A. ;
Marsh, Robert A. ;
McNeill, Christopher R. ;
Friend, Richard H. ;
Greenham, Neil C. .
NANO LETTERS, 2008, 8 (11) :3942-3947
[6]   Correlation between chain packing and photoluminescence for PPV/PPE in macroscopically oriented state: Side chain effects [J].
Carbonnier, B ;
Egbe, DAM ;
Birckner, E ;
Grummt, UW ;
Pakula, T .
MACROMOLECULES, 2005, 38 (18) :7546-7554
[7]   Polymer solar cells with enhanced open-circuit voltage and efficiency [J].
Chen, Hsiang-Yu ;
Hou, Jianhui ;
Zhang, Shaoqing ;
Liang, Yongye ;
Yang, Guanwen ;
Yang, Yang ;
Yu, Luping ;
Wu, Yue ;
Li, Gang .
NATURE PHOTONICS, 2009, 3 (11) :649-653
[8]   Efficient Polymer Solar Cells with Thin Active Layers Based on Alternating Polyfluorene Copolymer/Fullerene Bulk Heterojunctions [J].
Chen, Mei-Hsin ;
Hou, Jianhui ;
Hong, Ziruo ;
Yang, Guanwen ;
Sista, Srinivas ;
Chen, Li-Min ;
Yang, Yang .
ADVANCED MATERIALS, 2009, 21 (42) :4238-+
[9]   Transient absorption spectroscopy of charge photogeneration yields and lifetimes in a low bandgap polymer/fullerene film [J].
Clarke, Tracey ;
Ballantyne, Amy ;
Jamieson, Fiona ;
Brabec, Christoph ;
Nelson, Jenny ;
Durrant, James .
CHEMICAL COMMUNICATIONS, 2009, (01) :89-91
[10]   Charge Photogeneration in Organic Solar Cells [J].
Clarke, Tracey M. ;
Durrant, James R. .
CHEMICAL REVIEWS, 2010, 110 (11) :6736-6767