Dye-sensitized Solar Cells (DSCs)

Solar-derived electricity will likely play a substantial role in meeting the rising demand for energy in general and, more specifically, for energy from carbon-neutral sources. Dyesensitized solar cells (DSCs), comprising chromophores, redox shuttles, and nanoporous semiconductors, have shown considerable promise as low-tech alternatives to ubiquitous, but pricey, silicon-based photovoltaics.The most efficient DSCs display light-to-electrical energy conversion efficiencies of just over 12%. Obviously, in order for DSCs to attain higher efficiencies and become genuinely competitive with silicon technology, efficiencies, and therefore, photovoltages, photocurrent densities, or both, must be increased. One approach to boosting photocurrents is to employ multiple dye types (“co-sensitization”) rather than a single type, thereby broadening spectral coverage and enhancing light harvesting efficiencies (LHEs). A second general idea, applicable to increasing both open-circuit photovoltages (Voc) and shortcircuit photocurrent densities (Jsc) is to decrease the rate at which injected electrons are lost to recombination with the oxidized dye, or more commonly, the oxidized redox shuttle. To the extent the loss or recombination rate can be diminished, the effective electron collection length, Leff, can be increased. Leff is the average distance an injected electron travels through the photoanode before recombining; electrons injected at distances greater than Leff from the current collector will be collected with only low probability and, therefore, will seldom contribute to the photocurrent. Larger effective-collectionlengths allow thicker (i.e., higher surface area) photoelectrodes to be productively used, resulting in greater dye loading, larger LHEs, and larger photocurrents.

Related Papers

“A Ruthenium Complex as a Single-Component Redox Shuttle for Electrochemical Photovoltaics”
Jeung Yoon Kim, Won Seok Yoon, Ho-Jin Son, JaeDong Lee, Nak Cheon Jeong*
Chem. Commun. 2015, 51, 7745-7748. (Publication Date: 2015.05.04)

“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*
JACS 2012, 134, 19820-19827. (Publication date: 2012.12.05)

“Fast Transporting ZnO-TiO₂ Coaxial Photoanodes for Dye-Sensitized Solar Cells Based on ALD-modified SiO₂ Aerogel Frameworks”
Vennesa O. Williams, Nak Cheon Jeong, Chaiya Prasittichai, Omar K. Farha, Michael J. Pellin, Joseph T. Hupp*
ACS Nano 2012, 6, 6185-6196. (Publication date: 2012.7.24)

“Glass-encapsulated Light Harvesters: More Efficient Dye-sensitized Solar Cells by Deposition of Self-aligned, Conformal and Self-limited Silica Layers”
Ho-Jin Son, Xinwei Wang, Chaiya Prasittichai, Nak Cheon Jeong, Titta Aaltonen, Roy G. Gordon, Joseph T. Hupp*
JACS 2012, 134, 9537-9540. (Publication date: 2012.6.13)

“Photocurrent Enhancement by Surface Plasmon Resonance of Silver Nanoparticles in Highly Porous Dye-Sensitized Solar Cells”
Nak Cheon Jeong, Chaiya Prasittichai, Joseph T. Hupp*
Langmuir 2011, 27, 14609-14614. (Publication date: 2011.12.6)

“A Convenient Route to High Area, Nanoparticulate TiO₂ Photoelectrodes Suitable for High-efficiency Energy Conversion in Dye-Sensitized Solar Cells”
Nak Cheon Jeong, Omar K. Farha, Joseph T. Hupp*
Langmuir 2011, 27, 1996-1999. (Publication date: 2011.3.1)

“Porphyrin Sensitized Solar Cell: TiO₂ Sensitization with a p-extended porphyrin possessing two anchoring groups ”
Chang Yeon Lee, Chunxing She, Nak Cheon Jeong, Joseph T. Hupp*
Chem. Commun. 2010, 46, 6090-6092. (Publication date: 2010.9.7)

Figure. Photograph of a two-color photoanode.

Figure. (a) Photographs of: TMAOH-based and TBAOH-based TiO₂ NPs for dye-sensitized solar cells. (b) Schematic illustration of surface plasmonic silver nanoparticles-deposited on TiO₂ nanoparticle for dye-sensitized solar cells. (c) JV curves of mixed (blue) and separated co-sensitization with an organic dye and Zn-porphyrin dye.

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