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

ABSTRACT: 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

SUBMITTER: Fish GC 

PROVIDER: S-EPMC8549113 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature