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Band Gap Tuning in Composites of Polypyrrole Derivatives and C 60 Pd 3 Polymer as Models for p–n Junction: A First Principle Computational Study
Author(s) -
Goclon Jakub,
Winkler Krzysztof
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201702752
Subject(s) - polypyrrole , substituent , homo/lumo , pyrrole , palladium , materials science , binding energy , band gap , polymer , chemistry , crystallography , composite material , stereochemistry , organic chemistry , molecule , atomic physics , polymerization , physics , catalysis , optoelectronics
In this work, the electronic properties of a substituted polypyrrole (PPy−R) deposited on a palladium–fullerene polymer (C 60 Pd 2 (‐2Pd)) were obtained by first principles DFT+vdW calculations. By introducing both electron‐withdrawing (COOH) and electron‐donating (NH 2 ) substituents into the polypyrrole chain, we modulated the HOMO and LUMO levels of PPy−R/C 60 Pd 2 (‐2Pd). Furthermore, we also determined the influence of the second COOH group in each pyrrole ring and the CH 3 group linked to the nitrogen atom on the electronic properties. The calculated data show that the type of substituent, as well as the termination of the palladium–fullerene polymer, strongly influences the band gap. The general picture of the mixed systems reveals that the HOMO corresponds to that of PPy/PPy−R and the LUMO corresponds to that of C 60 Pd 2 (‐2Pd). For isolated PPy−R, the substituent strongly influences the relative position of the HOMO and LUMO levels toward the vacuum level, and, based on this fact, we can easily tune the band gap of the mixed systems. For the sake of completeness, all configurations, as well as the corresponding total binding energies, were carefully analysed and compared. The adsorption of PPy(‐R) on the Pd‐terminated C 60 Pd 2 led to the formation of surface Py⋅⋅⋅Pd complexes that have higher binding energies than in the case of the C 60 ‐terminated polymer. Furthermore, composites with two PPy chains on C 60 Pd 2 (‐2Pd) were also studied.