TY - JOUR
T1 - Understanding the Double Doping of Organic Semiconductors Via State Energy Renormalization upon Charging
AU - Warren, Ross
AU - Cho, Eunkyung
AU - Li, Hong
AU - Bredas, Jean Luc
AU - Koch, Norbert
N1 - Funding Information:
The work in Berlin was supported by the Deutsche Forschungsgemeinschaft (Project No. 182087777-SFB951). The work at the University of Arizona was funded by the UA College of Science and the Office of Naval Research, Award No. N00014-20-1-2110. The authors acknowledge the use of High-Performance Computing (HPC) resources supported by Research Data Center (RDC) at the University of Arizona.
Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.
PY - 2022/10/3
Y1 - 2022/10/3
N2 - The double ionization of molecular dopants enables the doping efficiency (free charges per dopant molecule) to rise above 100%. However, the current models of doped organic semiconductors based on Fermi-Dirac statistics fail to explain the double ionization of dopants and also the analogous situation of bipolaron formation on a host polymer. Here, we address this shortcoming by considering the renormalization of the state energies upon electron transfer between host and p-dopant. We vary the model parameters-the reorganization energy and evolutions of ionization energies and electron affinities upon charging-and plot the fractions of doubly ionized, singly ionized, and neutral species. The model shows good agreement with experimental measurements of doubly ionized p-dopants and bipolarons on a p-doped polymer. With these insights, we suggest that the state energy renormalization upon charging is the key parameter to be minimized for double ionization of dopants or maximized to avoid formation of bipolarons on the host.
AB - The double ionization of molecular dopants enables the doping efficiency (free charges per dopant molecule) to rise above 100%. However, the current models of doped organic semiconductors based on Fermi-Dirac statistics fail to explain the double ionization of dopants and also the analogous situation of bipolaron formation on a host polymer. Here, we address this shortcoming by considering the renormalization of the state energies upon electron transfer between host and p-dopant. We vary the model parameters-the reorganization energy and evolutions of ionization energies and electron affinities upon charging-and plot the fractions of doubly ionized, singly ionized, and neutral species. The model shows good agreement with experimental measurements of doubly ionized p-dopants and bipolarons on a p-doped polymer. With these insights, we suggest that the state energy renormalization upon charging is the key parameter to be minimized for double ionization of dopants or maximized to avoid formation of bipolarons on the host.
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U2 - 10.1021/acsmaterialslett.2c00619
DO - 10.1021/acsmaterialslett.2c00619
M3 - Article
AN - SCOPUS:85139304897
SN - 2639-4979
VL - 4
SP - 2051
EP - 2057
JO - ACS Materials Letters
JF - ACS Materials Letters
IS - 10
ER -