Effective panchromatic sensitization of electrochemical solar cells: Strategy and organizational rules for spatial separation of complementary light harvesters on high-area photoelectrodes

Nak Cheon Jeong*, Ho Jin Son, Chaiya Prasittichai, Chang Yeon Lee, Rebecca A. Jensen, Omar k Farha, Joseph T Hupp

*Corresponding author for this work

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

Dye-sensitized solar cells, especially those comprising molecular chromophores and inorganic titania, have shown promise as an alternative to silicon for photovoltaic light-to-electrical energy conversion. Co-sensitization (the use of two or more chromophores having complementary absorption spectra) has attracted attention as a method for harvesting photons over a broad spectral range. If implemented successfully, then cosensitization can substantially enhance photocurrent densities and light-to-electrical energy conversion efficiencies. In only a few cases, however, have significant overall improvements been obtained. In most other cases, inefficiencies arise due to unconstructive energy or charge transfer between chromophores or, as we show here, because of modulation of charge-recombination behavior. Spatial isolation of differing chromophores offers a solution. We report a new and versatile method for fabricating two-color photoanodes featuring spatially isolated chromophore types that are selectively positioned in desired zones. Exploiting this methodology, we find that photocurrent densities depend on both the relative and absolute positions of chromophores and on "local" effective electron collection lengths. One version of the two-color photoanode, based on an organic push-pull dye together with a porphyrin dye, yielded high photocurrent densities (JSC = 14.6 mA cm-2) and double the efficiency of randomly mixed dyes, once the dyes were optimally positioned with respect to each other. We believe that the organizational rules and fabrication strategy will prove transferrable, thereby advancing understanding of panchromatic sensitization as well as yielding higher efficiency devices.

Original languageEnglish (US)
Pages (from-to)19820-19827
Number of pages8
JournalJournal of the American Chemical Society
Volume134
Issue number48
DOIs
StatePublished - Dec 5 2012

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Fingerprint Dive into the research topics of 'Effective panchromatic sensitization of electrochemical solar cells: Strategy and organizational rules for spatial separation of complementary light harvesters on high-area photoelectrodes'. Together they form a unique fingerprint.

  • Cite this