Charge Photogeneration Dynamics of Poly(3-hexylthiophene) Blend with Covalently-Linked Fullerene Derivative in Low Fraction

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• 作者：Ning-Jiu Zhao ; Zi-Hong Lin ; Wei Zhang ; Juan Liu ; Yu-Wei Wang ; Yu-Jun Qin ; Xi-Cheng Ai ; Zhi-Xin Guo ; Jian-Ping Zhang
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：September 18, 2014
• 年：2014
• 卷：118
• 期：37
• 页码：21377-21384
• 全文大小：477K
• ISSN：1932-7455

文摘

Exciton and charge dynamics of poly(3-hexylthiophene) (P3HT) blended with covalently linked monomeric (MP), dimeric (BP), or trimeric (TP) fullerene derivatives are investigated by using near-infrared time-resolved absorption spectroscopy under low excitation photon fluence. A low blending ratio (10%, w/w) of the fullerene derivative allows us to examine the effect of linked-fullerene number on charge photogeneration. With reference to P3HT:MP, the P3HT:BP blend shows a one-fold higher exciton dissociation rate and significantly alleviated nongeminate charge recombination in spite of a similar P3HT packing order. However, TP with even larger size tends to aggravate the geminate and nongeminate recombination in picosecond-to-nanosecond time scales. The primary exciton and charge dynamics are discussed in correlation with the nanoscopic film morphology. The results suggest that the dumbbelled fullerene derivative BP as an electron-withdrawing material is promising in boosting the free charge photoproduction in polymer solar cells.