Project

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Towards polymer solar cell with 10% efficiency - ultrafast electron transfer in new polycarbazole-fullerene blends

English title Towards polymer solar cell with 10% efficiency - ultrafast electron transfer in new polycarbazole-fullerene blends
Applicant Banerji Natalie
Number 125859
Funding scheme Fellowships for prospective researchers
Research institution Center for Polymers and Organic Solids Department of Chemistry and Biochemistry University of California (UCSB)
Institution of higher education Institution abroad - IACH
Main discipline Physical Chemistry
Start/End 01.09.2009 - 31.05.2011
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All Disciplines (2)

Discipline
Physical Chemistry
Material Sciences

Keywords (6)

polymer solar cells; bulk heterojunction materials; semiconducting polymers; poly(2,7-carbazole) derivatives; femtosecond-resolved spectroscopy; ultrafast phtoinduced electron transfer

Lay Summary (English)

Lead
Lay summary
In view of an increasing worldwide energy demand and problems encountered with fossil fuels (pollution, limited availability), the almost unlimited energy reaching us from the Sun appears as an obvious solution. This solar energy is however diffuse and difficult to catch, so that solar cell technologies are not yet competitive with the price of other energy resources. Among numerous new approaches to solar energy conversion is the development of plastic solar cells. Since the introduction of the bulk heterojunction concept by Heeger and co-workers in 1995 (Science 1995, 270, 1789), innovative research on polymer solar cells has enjoyed a steady increase in interest. Photovoltaic devices based on semiconducting polymers blended with fullerene derivatives combine the practicality of being light-weight and flexible with the low-cost ease of processing. In spite of those highly attractive features, their implementation has been limited by the relatively low light conversion efficiency (around 5%). During the planned post-doctoral stay with the group of Professor Alan J. Heeger (Nobel Prize in Chemistry 2000), the photoinduced electron transfer mechanism in new poly(2,7-carbazole)/fullerene blends will be investigated by ultrafast spectroscopy. The new class of poly(2,7-carbazoles), promises solar cell efficiency beyond 10%. The ultrafast studies are a significant step in the optimization of the solar cells, as they allow understanding charge carrier generation and recombination mechanisms, which are important parameters of light conversion efficiency. The project will be conducted in the framework of a larger interdisciplinary project at the "Center for Polymers and Organic Solids" (University of California at Santa Barbara), which includes synthesis and scale up of the poly(2,7-carbazole) materials, solar cell fabrication, evaluation and optimization as well as lifetime measurements on final devices.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Publications

Publication
Spectroscopy of charge carrier dynamics- from generation to collection
Cowan Sarah, Banerji Natalie (2013), Spectroscopy of charge carrier dynamics- from generation to collection, in Richter Henning, Rand Barry (ed.), 429-495.
Breaking Down the Problem: Optical Transitions, Electronic Structure, and Photoconductivity in Conjugated Polymer PCDTBT and in Its Separate Building Blocks
Banerji N., Gagnon E., Morgantin P. Y., Valouch S., Mohebbi A. R., Seo J. H., Leclerc M., Heeger A. J. (2012), Breaking Down the Problem: Optical Transitions, Electronic Structure, and Photoconductivity in Conjugated Polymer PCDTBT and in Its Separate Building Blocks, in Journal of Physical Chemistry C, 116, 11456-11469.
Charge Formation, Recombination, and Sweep-Out Dynamics in Organic Solar Cells
Cowan S. R., Banerji N., Leong W. L., Heeger A. J. (2012), Charge Formation, Recombination, and Sweep-Out Dynamics in Organic Solar Cells, in Advanced Functional Materials, 22, 1116-1128.
Identifying a threshold impurity level for organic solar cells: Enhanced first-order recombination via well-defined PC84BM traps in organic bulk heterojunction solar cells
Cowan Sarah R., Leong Wei Lin, Banerji Natalie, Dennler Gilles, Heeger Alan J. (2011), Identifying a threshold impurity level for organic solar cells: Enhanced first-order recombination via well-defined PC84BM traps in organic bulk heterojunction solar cells, in Advanced Functional Materials, 21(16), 3083.
Ultrafast Relaxation of the Poly(3-hexylthiophene) Emission Spectrum
Banerji Natalie, Cowan Sarah, Vauthey Eric, Heeger Alan J. (2011), Ultrafast Relaxation of the Poly(3-hexylthiophene) Emission Spectrum, in The Journal of Physical Chemistry C, 115, 9726-9739.
Ultrafast spectroscopic investigation of a fullerene poly(3-hexylthiophene) dyad
Banerji N., Seifter J., Wang M. F., Vauthey E., Wudl F., Heeger A. J. (2011), Ultrafast spectroscopic investigation of a fullerene poly(3-hexylthiophene) dyad, in Physical Review B, 84, 075206-075206.
Exciton formation, relaxation, and decay in PCDTBT
Banerji Natalie, Cowan Sarah, Leclerc Mario, Vauthey Eric, Heeger Alan J. (2010), Exciton formation, relaxation, and decay in PCDTBT, in Journal of the American Chemical Society, 132, 17459-17470.

Collaboration

Group / person Country
Types of collaboration
Fred Wudl/UCSB United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Eric Vauthey/University of Geneva Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Mario Leclerc/University of Laval Canada (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
MRS Spring Meeting Talk given at a conference 1) The Implications of Ultrafast Relaxation Processes in Pristine Conjugated Polymers on the Charge Separation Mechanism in Bulk Heterojunction Polymer:Fullerene Blends 25.04.2011 San Francisco, United States of America Banerji Natalie;
Materials research Society (MRS) Spring Meeting 2011 Talk given at a conference Comparing the Photophysics of a Conjugated Donor‐Acceptor Copolymer to the One of Its Monomeric Repeat Unit 25.04.2011 San Francisco, United States of America Banerji Natalie;


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