Excitation energy-dependent photocurrent switching in a single-molecule photodiode.


Journal Article

The direction of electron flow in molecular optoelectronic devices is dictated by charge transfer between a molecular excited state and an underlying conductor or semiconductor. For those devices, controlling the direction and reversibility of electron flow is a major challenge. We describe here a single-molecule photodiode. It is based on an internally conjugated, bichromophoric dyad with chemically linked (porphyrinato)zinc(II) and bis(terpyridyl)ruthenium(II) groups. On nanocrystalline, degenerately doped indium tin oxide electrodes, the dyad exhibits distinct frequency-dependent, charge-transfer characters. Variations in the light source between red-light (∼1.9 eV) and blue-light (∼2.7 eV) excitation for the integrated photodiode result in switching of photocurrents between cathodic and anodic. The origin of the excitation frequency-dependent photocurrents lies in the electronic structure of the chromophore excited states, as shown by the results of theoretical calculations, laser flash photolysis, and steady-state spectrophotometric measurements.

Full Text

Duke Authors

Cited Authors

  • Shan, B; Nayak, A; Williams, OF; Yost, DC; Polizzi, NF; Liu, Y; Zhou, N; Kanai, Y; Moran, AM; Therien, MJ; Meyer, TJ

Published Date

  • August 2019

Published In

Volume / Issue

  • 116 / 33

Start / End Page

  • 16198 - 16203

PubMed ID

  • 31366631

Pubmed Central ID

  • 31366631

Electronic International Standard Serial Number (EISSN)

  • 1091-6490

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.1907118116


  • eng