Kinetic Studies of Geminate Polaron Pair Recombination, Dissociation, and Efficient Triplet Exciton Formation in PC:PCBM Organic Photovoltaic Blends
Kinetic Studies of Geminate Polaron Pair Recombination, Dissociation, and Efficient Triplet Exciton Formation in PC:PCBM Organic Photovoltaic Blends
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DOI：
10.1021/jp208820g
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发表时间：
2012-02
影响因子：
3.7
通讯作者：
E. Snedden;A. Monkman;F. Dias
中科院分区：
文献类型：
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作者：
E. Snedden;A. Monkman;F. Dias
利用飞秒瞬态吸收光谱研究了染料分子1,4,8,11,15,18,22,25-八叔甲氧基- 29h， 31h -酞菁（PC）与电子受体[6,6]-苯基- c61 -丁酸甲酯（PCBM）的体积异质结共混物中双极化子对（GPPs）的重组和解离。GPP状态的动力学是由PC的三重态的有效重组所主导的，这与GPP的解离相竞争，并从根本上减少了共混物中产生的自由极化子的总数。复合和解离都强烈依赖于共混形态，通过创造极化子离开界面区域的渗透途径，可以增加自由极化子的产量。然而，在这种条件下，在电子转移开始之前，PC域中的快速激子衰变就发生了，并进一步降低了自由极化子的产率。研究了这些因素对三元共混物太阳能电池运行的影响。
The recombination and dissociation of geminate polaron pairs (GPPs) in bulk-heterojunction blends of the dye molecule 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (PC) with the electron acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) is studied using femtosecond transient absorption spectroscopy. The kinetics of the GPP state is dominated by efficient recombination to the triplet state of the PC, which competes with GPP dissociation and acts to fundamentally reduce the total number of free polarons generated in the blend. Both recombination and dissociation are strongly dependent on the blend morphology, with increased free polaron yields obtained by creating percolation pathways for polarons to move away from interfacial regions. Under such conditions, however, rapid exciton decay within PC domains occurs before the onset of electron transfer and acts to further reduce the free polaron yield. The consequences of these factors on the operation of solar cells using ternary blends for n...