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Rectification and stability of a single molecular diode with controlled orientation
Ismael Díez-Pérez1, Joshua Hihath, Youngu Lee
1Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA.
Nature Chemistry
|March 8, 2011
Summary
Researchers engineered single molecules to function as diodes, achieving significant rectification in non-symmetric diblock molecules. This molecular diode behavior is crucial for advancing molecular electronics and nanoscale devices.
Area of Science:
- Molecular electronics
- Nanoscience
- Organic electronics
Background:
- Engineering molecular structure for specific functions is a key goal in molecular electronics.
- Single-molecule diode (rectification) behavior is a highly desirable device function.
Purpose of the Study:
- To investigate charge transport through symmetric tetraphenyl and non-symmetric diblock dipyrimidinyldiphenyl molecules.
- To control molecular orientation and determine current-voltage characteristics of single-molecule devices.
Main Methods:
- Covalent binding of molecules to electrodes.
- Selective deprotection strategy for controlling diblock orientation.
- Electrode-electrode distance modulation to determine current-voltage characteristics.
Main Results:
- Non-symmetric diblock molecules exhibit pronounced rectification behavior, superior to symmetric counterparts.
- Current flows preferentially from dipyrimidinyl to diphenyl moieties in the diblock molecule.
- Rectification is attributed to the localization of the hole ground state wave function.
Conclusions:
- Molecular diodes can be engineered for specific functions, demonstrating rectification.
- The observed rectification is explained by quantum mechanical effects within the molecule.
- Device instability and quantum point contact formation occur at high forward currents.
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