Abstract
While Organic photovoltaics (OPV) offer great promise as a low-cost renewable energy source, the relative low efficiency still challenges its commercialization potential. This challenge can be addressed with squaraine (SQ) molecules through unique material de-sign. Advantages of SQ over other materials, such as conjugate polymers, include its high extinction coefficients (>105), decent photo-stability, good synthetic reproducibility, and tunable molecular structure. The chemical properties of SQ dyes make them very suitable to form two pronounced aggregates in film: H- and J-aggregates. With small chemical modifications, the squaraines can have substantial impact on photophysical properties and aggregation pattern, and thus on operational OPV efficiency. In this work we comprehen-sively assign the spectral features of two squaraines: a dihydroxy squaraine, 2,4-bis-(4-dibutylamino-2,6-dihydroxyphenyl) cyclobutane-1,3-dione (DBSQ(OH)2) and a corre-sponding deshydroxy squaraine, 2,4-bis-(4-dibutylamino-phenyl)cyclobutane-1,3-dione (DBSQ) as the squaraines interact with each other in a range of different environments spanning dilute liquid solution with completely isolated molecules, concentrated solid so-lutions by working with polymethylmethacrylate films, and neat and blended films analo-gous to active layers for OPV devices. We then verified these assignments with materials characterization and testing of associated OPV devices. In general, the data follows a trend seen for many squaraines synthesized in our group that the presence (absence) of the OH groups. The superior performance of DBSQ(OH)2-based OPV devices suggests the benefit of incorporating OH groups into SQ molecule for OPV application.
Library of Congress Subject Headings
Solar cells--Materials; Photovoltaic power systems--Materials; Organic compounds--Optical properties
Publication Date
12-2015
Document Type
Thesis
Student Type
Graduate
Degree Name
Chemistry (MS)
Department, Program, or Center
School of Chemistry and Materials Science (COS)
Advisor
Christopher J. Collison
Advisor/Committee Member
Thomas W. Smith
Advisor/Committee Member
Jeremy A. Cody
Recommended Citation
Zheng, Chenyu, "Spectral Properties of Squaraines and Their Aggregates, Targeted for Use in Bulk Hetero-junction Solar Cells" (2015). Thesis. Rochester Institute of Technology. Accessed from
https://repository.rit.edu/theses/8923
Campus
RIT – Main Campus
Plan Codes
CHEM-MS
Comments
Physical copy available from RIT's Wallace Library at TK2960 .Z44 2015