聚合物基体中的三苯胺-萘二酰亚胺二酰亚胺极长寿命的光诱导电荷分离态,The Journal of Physical Chemistry A

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聚合物基体中的三苯胺-萘二酰亚胺二酰亚胺极长寿命的光诱导电荷分离态
The Journal of Physical Chemistry A ( IF 2.7 ) Pub Date : 2016-10-06 00:00:00 , DOI: 10.1021/acs.jpca.6b07705
Kenshi Kimoto ₁ , Tsubasa Satoh ₁ , Munetaka Iwamura ₁ , Koichi Nozaki ₁ , Takafumi Horikoshi ₂ , Shuichi Suzuki ₂ , Masatoshi Kozaki ₂ , Keiji Okada ₂

Affiliation

研究了含有三苯胺（MTA）和萘二酰亚胺（MNDI）与分散在聚苯乙烯（PS），聚氯乙烯和聚甲基丙烯酸甲酯的刚性聚合物基质中的低聚亚苯基亚乙炔基相连的二联体（dyad1和dyad2）中的光诱导电子转移）。这些二元体系的光激发产生长寿命的电荷分离（CS）规定涉及MTA ⁺和MNDI ^-。在聚合物基质中，dyad1和dyad2中电荷分离的量子产率分别约为0.4和0.3。dyad2的CS寿命PS在298 K下的时间（400 ms）比聚氯乙烯（120 ms）和聚甲基丙烯酸甲酯（65 ms）更长（400 ms）。此外，在玻璃状甲苯中，CS态的寿命非常长，为5.4 s在100 K下。在玻璃化转变温度以下，具有各种弛豫速率的聚合物侧链运动应会影响电荷重组过程。电荷重组过程中的能隙（ΔG）和外层重组能量（λ）是使用介电常数的慢频率分量估算的。通过使用ΔG和λ值，基于Marcus理论成功地理化了CS寿命的矩阵依赖性，并且低极性和高极化率的PS中的电荷复合过程应该在比其他聚合物矩阵更深的反向区域中。还表明聚合物的刚性有效地抑制了分子内运动，从而促进了电荷复合过程。

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Very Long-Lived Photoinduced Charge-Separated States of Triphenylamine–Naphthalenediimide Dyads in Polymer Matrices

Photoinduced electron transfer was studied in dyads (dyad1 and dyad2) containing triphenylamine (MTA) and naphthalenediimide (MNDI) linked with oligo(phenyleneethynylene) dispersed in rigid polymer matrices of polystyrene (PS), poly(vinyl chloride), and poly(methyl methacrylate). Photoexcitation of these dyads yielded long-lived charge-separated (CS) states involving MTA⁺ and MNDI^–. The quantum yields of charge separation in dyad1 and dyad2 were approximately 0.4 and 0.3, respectively, in the polymer matrices. The CS lifetime for dyad2 in PS was longer (400 ms) than those in poly(vinyl chloride) (120 ms) and poly(methyl methacrylate) (65 ms) at 298 K. In addition, CS state had a very long lifetime of 5.4 s in glassy toluene at 100 K. Below glass transition temperatures, polymer side chain motions with various relaxation rates should affect the charge recombination processes. The energy gap (ΔG) and outer-sphere reorganization energy (λ) in the charge recombination process were estimated using a slow-frequency component for dielectric constants. By use of ΔG and λ values, the matrix dependence of the CS lifetimes was successfully rationalized based on Marcus theory, and the charge recombination process in PS with low polarity and high polarizability should be in a deeper inverted region than the other polymer matrices. It also suggested that the rigidity of the polymer effectively suppressed intramolecular motions promoting the charge recombination process.

更新日期：2016-10-06

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