Photophysical and electronic properties of five PCBM-like C60 derivatives: spectral and quantum chemical view.
Photophysical and electronic properties of five PCBM-like C60 derivatives: spectral and quantum chemical view.
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DOI：
10.1021/jp208520v
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发表时间：
2012-01
期刊：
影响因子：
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通讯作者：
Huan Wang;Youjun He;Yongfang Li;Hongmei Su
中科院分区：
文献类型：
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作者：
Huan Wang;Youjun He;Yongfang Li;Hongmei Su
本工作通过瞬时紫外-可见吸收光谱/荧光光谱，结合电子结构计算，表征了五个类PCBM C(60)衍生物(F1、F2、F3、F4和F5)的光物理和电子性质，并了解这些性质将如何影响以这些分子为受体的聚合物太阳能电池(PSCs)的光伏性能。光谱数据表明，与原始C(60)相比，五个类PCBM型C(60)的荧光量子产率(Φ(F))提高，三重态量子产率(Φ(T))降低，这表明C-═C双键的官能化扰乱了富勒烯的π-体系，破坏了原始C(60)的I(H)对称性，从而导致了富勒烯衍生物的光物理性质的改变。PBEPBE/6-311G(d，p)//PBEPBE/6-31G(D)水平的电子结构计算得到了HOMO-LUMO能级和LUMO能级，表明侧链官能团引起的电子吸引效应扰动了LUMO能级，从而产生了不同的开路电压V(Oc)。由我们的计算预测的V(Oc)与以前的实验结果一致。基本上，我们发现C-═-C双键的官能化维持了富勒烯的结构及其电子亲和性质。加成侧链有助于调节受体的HOMO-LUMO间隙和LUMO水平，以改善开路电压。这一结果可以为理解结构修饰对光伏性能的影响提供基础的见解，为合成性能更好的新型富勒烯衍生物在聚合物太阳能电池中的应用铺平道路。
By means of transient UV-visible absorption spectra/fluorescence spectra, combined with electronic structure calculations, the present work focuses on characterizing the photophysical and electronic properties of five PCBM-like C(60) derivatives (F1, F2, F3, F4, and F5) and understanding how these properties are expected to affect the photovoltaic performance of polymer solar cells (PSCs) with those molecules as acceptors. Spectral data reveal that the fluorescence quantum yields (Φ(F)) are enhanced and the triplet quantum yields (Φ(T)) are lowered for the five PCBM-like C(60) derivatives as compared to those of the pristine C(60), suggesting that functionalization of a C═C double bond perturbs the fullerene's π-system and breaks the I(h) symmetry of pristine C(60), which results in modifications of photophysical properties of the fullerene derivatives. PBEPBE/6-311G(d,p)//PBEPBE/6-31G(d) level of electronic structure calculations yields the HOMO-LUMO gaps and LUMO energies, showing that the electron-withdrawing effect induced by the side chain functional groups perturbs LUMO energies, from which different open circuit voltages V(oc) are resulted. The predicted V(oc) from our calculation agrees with previous experiment results. Basically, we found that functionalization of a C═C double bond sustains the fullerene structure and its electron affinitive properties. Adducted side chains contribute to adjust the HOMO-LUMO gap and LUMO levels of the acceptors to improve open circuit voltage. The results could provide fundamental insights for understanding how structural modifications influence the photovoltaic performance, which paves a way for guiding the synthesis of new fullerene derivatives with improved performance in polymer solar cells.