MORPHOLOGY STUDY OF ORGANIC PHOTOVOLTAIC MATERIALS AND ELECTROACTIVE POLYMERS
Open Access
Author:
Main, Alexei Seresin
Graduate Program:
Chemistry
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
March 31, 2008
Committee Members:
John B Asbury, Thesis Advisor/Co-Advisor
Keywords:
solar energy organic photovoltaics nanoimprint lithography anisotropy electroactive polymers
Abstract:
Ultrafast infrared polarization resolved pump/probe spectroscopy was used to study the anisotropy of the electroactive polymer 2-ethylhexyl acrylate (EHA). An anisotropy of 0.48 +/- 0.01 was observed, suggesting a preexisting molecular ordering in the EHA polymer film. Nanoimprint lithography (NIL) was used to produce nanoscale features on thin polymer films of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene]
(MEH-PPV) and sodium poly[2-(3-thienyl)ethoxy-4butylsulfonate] (PTEBS) with a periodicity of 750nm and a maximum depth of 80nm. The electron acceptor C60 was thermally deposited on top of the polymer film. By using NIL to imprint nanoscale features, the electron donor and acceptor in an organic photovoltaic cell will be closer to one another, hopefully leading to an increase in device efficiency. Atomic force microscopy, UV-VIS spectroscopy, and FTIR spectroscopy were used to study these polymer films. Future work will use transient absorption spectroscopy along with 2DIR spectroscopy to study the charge transfer dynamics in films with and without imprinting.
