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Synthesis of Single-Crystalline Core-Shell Metal-Organic Frameworks
Published on: February 10, 2023
Enforced one-dimensional photoconductivity in core-cladding hexabenzocoronenes.
Yaron S Cohen1, Shengxiong Xiao, Michael L Steigerwald
1Department of Chemistry, Columbia University, New York, New York 10027, USA.
Nano Letters
|December 14, 2006
Summary
Photoconductivity in contorted hexabenzocoronene liquid crystals is strictly one-dimensional. This unique property arises from distinct pi-systems, influencing charge transport and recombination dynamics.
Area of Science:
- Organic electronics
- Materials science
- Condensed matter physics
Background:
- Contorted hexabenzocoronenes (cHBCs) are promising organic semiconductors.
- Liquid crystalline phases offer ordered molecular arrangements for charge transport.
- Understanding charge transport mechanisms is crucial for device applications.
Purpose of the Study:
- To investigate the dimensionality of photoconductivity in cHBC liquid crystals.
- To elucidate the relationship between molecular structure and charge transport.
- To analyze the factors influencing photocurrent and recombination.
Main Methods:
- Spectroscopic measurements (e.g., UV-Vis, fluorescence).
- Density Functional Theory (DFT) calculations.
- Photocurrent measurements as a function of applied field, channel length, and light intensity.
Main Results:
- Photoconductivity was confirmed to be exclusively one-dimensional.
- Two distinct pi-systems were identified: a low-energy radialene core and higher-energy alkoxyphenyl rings.
- Persistent photocurrents followed a stretched exponential behavior, indicating intracolumnar transport.
- Alkoxyphenyl groups were found to restrict transport through the radialene core.
- Bimolecular recombination increased with carrier concentration due to one-dimensionality.
Conclusions:
- The one-dimensional nature of photoconductivity in cHBC liquid crystals is established.
- Molecular design, specifically the radialene core and alkoxyphenyl cladding, dictates charge transport pathways.
- The system's dimensionality significantly impacts carrier recombination kinetics.
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