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


Document Type


Student Type


Degree Name

Chemistry (MS)

Department, Program, or Center

School of Chemistry and Materials Science (COS)


Christopher J. Collison

Advisor/Committee Member

Thomas W. Smith

Advisor/Committee Member

Jeremy A. Cody


Physical copy available from RIT's Wallace Library at TK2960 .Z44 2015


RIT – Main Campus

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