TY - JOUR
T1 - Linear optical properties and electronic structures of poly(3- hexylthiophene) and poly(3-hexylselenophene) crystals from first principles
AU - Tsumuraya, Takao
AU - Song, Jung Hwan
AU - Freeman, Arthur J.
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012/8/8
Y1 - 2012/8/8
N2 - Linear optical properties of regio-regular-poly(3-hexythiophene) (rr-P3HT) and regio-regular-poly(3-hexyselenophene) (rr-P3HS) are investigated in relation to their anisotropic crystal structure by means of first-principles density functional calculations. The optical spectra are evaluated by calculating its dielectric functions, focusing on the frequency dependence of the imaginary part. The optical transition along the π conjugation-connecting backbone direction is found to be the most significant at the band edges. A group-theoretical analysis of the matrix elements is given to explain the interband transitions. The optical spectra, electronic structures, and structural stabilities are calculated using the all-electron full-potential linearized augmented plane wave (FLAPW) method within the local-density approximation. We proposed several possible crystal structures of rr-P3HT and performed structural optimizations to determine a stable structure. Comparing the total energy differences among these relaxed structures, a base-centered monoclinic structure belonging to the space group A2 is found to be the most stable structure. In the electronic structure, C and S orbitals belonging to polythiophene backbones are the biggest contributors at the valence band maximum and conduction band minimum, but there is almost no contribution from the hexyl side chains. Last, the differences in electronic and optical properties between rr-P3HT and rr-P3HS are discussed.
AB - Linear optical properties of regio-regular-poly(3-hexythiophene) (rr-P3HT) and regio-regular-poly(3-hexyselenophene) (rr-P3HS) are investigated in relation to their anisotropic crystal structure by means of first-principles density functional calculations. The optical spectra are evaluated by calculating its dielectric functions, focusing on the frequency dependence of the imaginary part. The optical transition along the π conjugation-connecting backbone direction is found to be the most significant at the band edges. A group-theoretical analysis of the matrix elements is given to explain the interband transitions. The optical spectra, electronic structures, and structural stabilities are calculated using the all-electron full-potential linearized augmented plane wave (FLAPW) method within the local-density approximation. We proposed several possible crystal structures of rr-P3HT and performed structural optimizations to determine a stable structure. Comparing the total energy differences among these relaxed structures, a base-centered monoclinic structure belonging to the space group A2 is found to be the most stable structure. In the electronic structure, C and S orbitals belonging to polythiophene backbones are the biggest contributors at the valence band maximum and conduction band minimum, but there is almost no contribution from the hexyl side chains. Last, the differences in electronic and optical properties between rr-P3HT and rr-P3HS are discussed.
UR - http://www.scopus.com/inward/record.url?scp=84865067198&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84865067198&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.86.075114
DO - 10.1103/PhysRevB.86.075114
M3 - Article
AN - SCOPUS:84865067198
VL - 86
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 7
M1 - 075114
ER -