Fullerene derivatives A-3PV and B-3PV in which an oligophenylenevinylene trimeric subunit (3PV) is attached to C60 through, respectively, a pyrrolidine or a pyrazoline ring have been prepared. The electrochemical and excited-state properties of the multicomponent arrays A-3PV and B-3PV have been investigated in solution using the related oligophenylenevinylene derivative 3PV, fullerenopyrrolidine A and fullerenopyrazoline B as reference compounds. In A-3PV quantitative OPV → C60 photoinduced singlet–singlet energy transfer has been observed. Population of the lowest fullerene singlet excited state is followed by nearly quantitative
intersystem crossing to the lowest fullerene triplet excited state in CH2Cl2 and toluene, whereas OPV → C60 electron transfer is able to compete significantly in the more polar solvent benzonitrile. In the case of B-3PV, the excited-state properties are more complex due to the electron donating ability of the pyrazoline ring. As observed for A-3PV, quantitative OPV → C60 photoinduced singlet–singlet energy transfer occurs in B-3PV. However, in this case, the population of the lowest fullerene singlet excited state is followed by an efficient electron transfer from the pyrazoline ring in CH2Cl2 and benzonitrile. In B-3PV, studies of the dependence of photoinduced processes on solvent polarity, addition of acid, and temperature
also reveal that this compound can be considered as a fullerene-based molecular switch, the switchable parameters being the photoinduced processes. Finally, A-3PV and B-3PV have been tested as active materials in photovoltaic devices and the differences of light to energy conversion efficiencies found for the two compounds have been rationalised on the basis of their photophysical properties.
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富勒烯衍
生物 A-3PV 和 B-3PV,其中低聚亚苯基
乙烯三聚亚基(3PV)分别通过
吡咯烷环或
吡唑啉环连接到 C60 上。以相关的低聚亚苯基
乙烯衍
生物 3PV、
富勒烯吡咯烷 A 和
富勒烯吡唑啉 B 为参考化合物,研究了多组分阵列 A-3PV 和 B-3PV 在溶液中的电
化学和激发态特性。在 A-3PV 中观察到了定量 OPV → C60 光诱导的单线窦-单线窦能量转移。在
CH2Cl2 和
甲苯中,最低
富勒烯单线激发态的流行几乎是定量的系统间交叉到最低
富勒烯三线激发态,而在极性更强的溶剂
苯甲腈中,OPV → C60 的电子转移能够产生明显的竞争。对于 B-3PV,由于
吡唑啉环具有电子捐赠能力,其激发态特性更为复杂。与在 A-3PV 中观察到的情况一样,在 B-3PV 中也发生了定量的 OPV → C60 光诱导单线窦-窦能量转移。不过,在这种情况下,最低
富勒烯单线激发态的能量传递是通过
吡唑啉环在 和
苯甲腈中的高效电子转移进行的。在 B-3PV 中,对光诱导过程对溶剂极性、酸的添加和温度的依赖性的研究也表明,这种化合物可被视为一种基于
富勒烯的分子开关,其可切换参数就是光诱导过程。最后,A-3PV 和 B-3PV 作为活性材料在光伏设备中进行了测试,并根据其光物理性质合理解释了两种化合物光能转换效率的差异。