TY - JOUR
T1 - Spontaneous Charge Transfer and Dipole Formation at the Interface Between P3HT and PCBM
AU - Aarnio, Harri
AU - Sehati, Parisa
AU - Braun, Slawomir
AU - Nyman, Mathias
AU - de Jong, Machiel Pieter
AU - Fahlman, Mats
AU - Österbacka, Ronald
N1 - 10.1002/aenm.201100074
PY - 2011/10
Y1 - 2011/10
N2 - In the pursuit of developing new materials for more effi cient bulk-heterojunction solar cells, the blend poly (3-hexylthiophene):[6,6]-phenyl-C 61 -butyric acid methyl ester (P3HT:PCBM) serves as an important model system. The success of the P3HT:PCBM blend comes from effi cient charge
generation and transport with low recombination. There is not, however, a good microscopic picture of what causes these, hindering the development of new material systems. In this report UV photoelectron spectroscopy measurements
on both regiorandom- (rra) and regioregular- (rr) P3HT are presented, and the results are interpreted using the Integer Charge Transfer model. The results suggest that spontaneous charge transfer from P3HT to PCBM occurs after heat treatment of P3HT:PCBM blends. The resulting formation of an interfacial dipole creates an extra barrier at the interface explaining the reduced (non-)geminate recombination with increased charge generation in heat treated rr-P3HT:PCBM blends. Extensive photoinduced absorption measurements using both above- and below-bandgap excitation light are presented, in good agreement with the suggested dipole formation.
AB - In the pursuit of developing new materials for more effi cient bulk-heterojunction solar cells, the blend poly (3-hexylthiophene):[6,6]-phenyl-C 61 -butyric acid methyl ester (P3HT:PCBM) serves as an important model system. The success of the P3HT:PCBM blend comes from effi cient charge
generation and transport with low recombination. There is not, however, a good microscopic picture of what causes these, hindering the development of new material systems. In this report UV photoelectron spectroscopy measurements
on both regiorandom- (rra) and regioregular- (rr) P3HT are presented, and the results are interpreted using the Integer Charge Transfer model. The results suggest that spontaneous charge transfer from P3HT to PCBM occurs after heat treatment of P3HT:PCBM blends. The resulting formation of an interfacial dipole creates an extra barrier at the interface explaining the reduced (non-)geminate recombination with increased charge generation in heat treated rr-P3HT:PCBM blends. Extensive photoinduced absorption measurements using both above- and below-bandgap excitation light are presented, in good agreement with the suggested dipole formation.
KW - EWI-21088
KW - IR-79321
KW - METIS-287840
U2 - 10.1002/aenm.201100074
DO - 10.1002/aenm.201100074
M3 - Article
SN - 1614-6832
VL - 1
SP - 792
EP - 797
JO - Advanced energy materials
JF - Advanced energy materials
IS - 5
ER -