Through structural isomerism: positional effect of alkyne functionality on molecular optical properties.
Nakka Nagaraju1, Dushyant Kushavah1, Sunil Kumar1
1School of Basic Sciences, Advanced Materials Research Center, Indian Institute of Technology Mandi, Kamand, H.P, 175005, India. suman@iitmandi.ac.in.
Physical Chemistry Chemical Physics : PCCP
|January 20, 2022
Summary
This study investigated how alkyne placement affects donor-acceptor dyes for dye-sensitized solar cells (DSSCs). The CAPC dye, with alkyne as a π-spacer, showed superior optical and charge generation properties compared to PACC.
Area of Science:
- Materials Science
- Organic Chemistry
- Photovoltaics
Background:
- Alkyne functionality's impact on donor-acceptor molecular scaffolds is less studied than alkene's.
- Donor-acceptor (D-A) dyes are crucial for dye-sensitized solar cells (DSSCs).
Purpose of the Study:
- To synthesize and compare two isomeric D-A dyes (CAPC and PACC) with varying alkyne positions.
- To evaluate the effect of alkyne placement on optical, electrochemical, and charge generation properties.
- To identify efficient dyes for potential DSSC applications.
Main Methods:
- Synthesis of carbazole- and cyanoacrylic acid-based D-A dyes (CAPC and PACC).
- Photophysical characterization (UV-Vis absorption, emission).
- Electrochemical analysis (cyclic voltammetry).
- Transient absorption spectroscopy and fluorescence lifetime studies.
- Density Functional Theory (DFT) calculations.
Main Results:
- Both dyes featured carbazole (donor) and cyanoacrylic acid (acceptor) units with controlled π-conjugation via an alkyne group.
- CAPC, with alkyne as a π-spacer, demonstrated superior photophysical and charge generation characteristics for DSSCs compared to PACC.
- Equal conjugation lengths were achieved in both designs, isolating the effect of alkyne position.
Conclusions:
- The positional isomerism of the alkyne group significantly influences the performance of D-A dyes.
- CAPC exhibits promising properties for efficient dye-sensitized solar cell applications.
- Further research into alkyne-based D-A systems is warranted for optimizing photovoltaic materials.
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