Direct and Inverse Photoelectron Spectroscopy Evidence for a Revised Picture of Electronic States of Negative Polarons in n‐Doped C 60
[1];
[1]
- Department of Electrical and Computer Engineering Princeton University Princeton NJ 08544 USA
- Department of Chemistry and Biochemistry The University of Arizona Tucson AZ 85721‐0041 USA
- Renewable and Sustainable Energy Institute University of Colorado Boulder Boulder CO 80309 USA
- Renewable and Sustainable Energy Institute University of Colorado Boulder Boulder CO 80309 USA, National Renewable Energy Laboratory Chemistry and Nanoscience Center Golden CO 80401 USA
- Renewable and Sustainable Energy Institute University of Colorado Boulder Boulder CO 80309 USA, National Renewable Energy Laboratory Chemistry and Nanoscience Center Golden CO 80401 USA, Department of Chemistry University of Colorado Boulder Boulder CO 80309 USA, Department of Chemical and Biological Engineering University of Colorado Boulder Boulder CO 80303 USA
Abstract Determining the electronic levels associated with polarons, the fundamental charge carriers in organic semiconductors, is key to understanding the charge transport properties of these materials. Recent findings challenge the traditional view of these electronic levels by highlighting the importance of intra‐molecular Coulomb interactions in polarons. Experimental evidence was previously presented for a revised model of the negative polaron in the case of the polymer semiconductor poly(NDI2OD‐T 2 ); there, the addition of an excess electron was seen to lead to the emergence of a singly occupied state within the energy gap of the undoped material and an unoccupied state above the edge of the conduction states . Here, focus is on a small‐molecule semiconductor, C 60 , and spectral evidence is provided of a similar picture for the new states appearing upon polaron formation. Specifically, direct and inverse photoemission spectroscopy is used to investigate the density of states in C 60 films n‐doped with two dimeric dopants. The Coulomb interaction energy (Hubbard U ) of the C 60 anion is experimentally determined to be ≈1.1 eV, a value that aligns closely with theoretical predictions.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States); Princeton University, NJ (United States)
- Sponsoring Organization:
- US Department of the Navy, Office of Naval Research (ONR); USDOE; USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
- Grant/Contract Number:
- AC36-08GO28308; SC0012458
- OSTI ID:
- 2472976
- Report Number(s):
- NREL/JA--5900-91008; 2415336
- Journal Information:
- Advanced Functional Materials, Journal Name: Advanced Functional Materials; ISSN 1616-301X
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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