Understanding Novel Lewis Acid Doping Mechanisms in Organic Semiconductors
- Univ. of California, Santa Barbara, CA (United States)
Recent studies supported by this DOE grant have provided a more detailed understanding of the doping mechanism of organic semiconductors by the Lewis acid, tris(pentafluorophenyl)borane (BCF). Our studies have examined the intermolecular semiconductor-dopant interactions as well as the thermodynamic feasibility of different doping mechanisms. Most notably, we found a different proposed doping scheme is much more thermodynamically favoured (exergonic) than our proposed two-step BCF doping mechanism. The state-of-the-art experimental and theoretical techniques of High-Field Multi-Dimensional Solid State NMR spectroscopy and Time-Dependent Density Functional theory (TD-DFT) and DFT were employed in this work. The data obtained helped identify the structural details and intermolecular interactions which impact the organic semiconductor doping efficiency for BCF and how these compare to the case of doping by the standard integer charge transfer dopant molecule F4TCNQ. We have, for the first time, assigned specific chemical shift values for the F4TCNQ molecules clustered outside of polymer chains as well as those intercalated between the polymer backbones. Further, we provide theoretical support for a novel doping mechanism which combines those proposed in previous literature involving the evolution of hydrogen gas along with a doping species more complex than the simple BCF·H2O. While our previously proposed doping mechanism was found to be highly thermodynamically unfavorable, the formation of large anion [BCF(OH)(OH2)BCF]- is the key change making the proposed mechanism exergonic while the elimination of gaseous H2 helps drive the doping reaction.
- Research Organization:
- Univ. of California, Santa Barbara, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- SC0017659
- OSTI ID:
- 1854606
- Report Number(s):
- DOE-UCSB-17659; TRN: US2302962
- Country of Publication:
- United States
- Language:
- English
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