4.6 Article

Critical role of H-aggregation for high-efficiency photoinduced charge generation in pristine pentamethine cyanine salts

期刊

PHYSICAL CHEMISTRY CHEMICAL PHYSICS
卷 23, 期 41, 页码 23886-23895

出版社

ROYAL SOC CHEMISTRY
DOI: 10.1039/d1cp03251h

关键词

-

资金

  1. Swiss National Science Foundation (SNF) [200021_175729]
  2. National Center of Competence in Research Molecular Ultrafast Science and Technology (NCCR-MUST)
  3. Swiss National Science Foundation (SNF) [200021_175729] Funding Source: Swiss National Science Foundation (SNF)

向作者/读者索取更多资源

The study demonstrates that a decrease in H-aggregation in organic salt semiconductors leads to reduced charge transfer, however, carrier mobility remains largely unchanged as a decrease in energetic disorder helps alleviate trapping of charges by H-aggregates.
The mechanism of photoinduced symmetry-breaking charge separation in solid cyanine salts at the base of organic photovoltaic and optoelectronic devices is still debated. Here, we employ femtosecond transient absorption spectroscopy (TAS) to monitor the charge transfer processes occurring in thin films of pristine pentamethine cyanine (Cy5). Oxidized dye species are observed in Cy5-hexafluorophosphate salts upon photoexcitation, resulting from electron transfer from monomer excited states to H-aggregates. The charge separation proceeds with a quantum yield of 86%, providing the first direct proof of high efficiency intrinsic charge generation in organic salt semiconductors. The impact of the size of weakly coordinating anions on charge separation and transport is studied using TAS alongside electroabsorption spectroscopy and time-of-flight techniques. The degree of H-aggregation decreases with increasing anion size, resulting in reduced charge transfer. However, there is little change in carrier mobility, as despite the interchromophore distance increasing, the decrease in energetic disorder helps to alleviate the trapping of charges by H-aggregates.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.6
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据