TY - JOUR
T1 - Photophysics of Molecular-Weight-Induced Losses in Indacenodithienothiophene-Based Solar Cells
AU - Gasparini, Nicola
AU - Katsouras, Athanasios
AU - Prodromidis, Mamantos I.
AU - Avgeropoulos, Apostolos
AU - Baran, Derya
AU - Salvador, Michael
AU - Fladischer, Stefanie
AU - Spiecker, Erdmann
AU - Chochos, Christos L.
AU - Ameri, Tayebeh
AU - Brabec, Christoph J.
N1 - Publisher Copyright:
© 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - The photovoltaic performance and optoelectronic properties of a donor-acceptor copolymer are reported based on indacenodithienothiophene (IDTT) and 2,3-bis(3-(octyloxy)phenyl)quinoxaline moieties (PIDTTQ) as a function of the number-average molecular weight (Mn). Current-voltage measurements and photoinduced charge carrier extraction by linear increasing voltage (photo-CELIV) reveal improved charge generation and charge transport properties in these high band gap systems with increasing Mn, while polymers with low molecular weight suffer from diminished charge carrier extraction because of low mobility-lifetime (μτ) product. By combining Fourier-transform photocurrent spectroscopy (FTPS) with electroluminscence spectroscopy, it is demonstrate that increasing Mn reduces the nonradiative recombination losses. Solar cells based on PIDTTQ with Mn = 58 kD feature a power conversion efficiency of 6.0% and a charge carrier mobility of 2.1 × 10-4 cm2 V-1 s-1 when doctor bladed in air, without the need for thermal treatment. This study exhibits the strong correlations between polymer fractionation and its optoelectronics characteristics, which informs the polymer design rules toward highly efficient organic solar cells.
AB - The photovoltaic performance and optoelectronic properties of a donor-acceptor copolymer are reported based on indacenodithienothiophene (IDTT) and 2,3-bis(3-(octyloxy)phenyl)quinoxaline moieties (PIDTTQ) as a function of the number-average molecular weight (Mn). Current-voltage measurements and photoinduced charge carrier extraction by linear increasing voltage (photo-CELIV) reveal improved charge generation and charge transport properties in these high band gap systems with increasing Mn, while polymers with low molecular weight suffer from diminished charge carrier extraction because of low mobility-lifetime (μτ) product. By combining Fourier-transform photocurrent spectroscopy (FTPS) with electroluminscence spectroscopy, it is demonstrate that increasing Mn reduces the nonradiative recombination losses. Solar cells based on PIDTTQ with Mn = 58 kD feature a power conversion efficiency of 6.0% and a charge carrier mobility of 2.1 × 10-4 cm2 V-1 s-1 when doctor bladed in air, without the need for thermal treatment. This study exhibits the strong correlations between polymer fractionation and its optoelectronics characteristics, which informs the polymer design rules toward highly efficient organic solar cells.
KW - charge transport
KW - energetic losses
KW - indacenodithienothiophene
KW - molecular weight
KW - organic solar cells
UR - http://www.scopus.com/inward/record.url?scp=84938990629&partnerID=8YFLogxK
U2 - 10.1002/adfm.201501062
DO - 10.1002/adfm.201501062
M3 - Article
AN - SCOPUS:84938990629
SN - 1616-301X
VL - 25
SP - 4898
EP - 4907
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 30
ER -
