Photoconductivity of Low-Bandgap Polymer andPolymer: Fullerene Bulk Heterojunction Studied byConstant Photocurrent Method

Organic Photonics and Photovoltaics

卷:3

Novikov S. V.¹  Malov V. V.¹  Tameev A. R.¹  Vannikov A.V.¹  Khenkin M. V.²  Kazanskii A. G.² 

[1] A.N. Frumkin Institute of PhysicalChemistry and Electrochemistry of the Russian Academy of Sciences,Leninsky prosp. 31, Moscow 119071, Russia;

[2] M.V. Lomonosov Moscow StateUniversity, Faculty of Physics, Leninskie Gory, Moscow 119991 Russia;

关键词: photoconductivity;    constant photocurrentmethod;    organic solar cell;    density-of-states;    PTB7;    PCDTBT;    bulk heterojunction;   

DOI  :  10.1515/oph-2015-0011

来源: DOAJ

【 摘 要 】

Optical and photoelectric properties of modernphotosensitive polymers are of great interest due totheir prospects for photovoltaic applications. In particular,an investigation of absorption and photoconductivityedge of these materials could provide valuable information.For these purpose we applied the constant photocurrentmethod which has proved its efficiency for inorganicmaterials. PCDTBT and PTB7 polymers were used as objectsfor the study as well as their blends with a fullerenederivative PC71BM. The measurements by constant photocurrentmethod (CPM) show that formation of bulk heterojunction(BHJ) in the blends increases photoconductivityand results in a redshift of the photocurrent edgein the doped polymers compared with that in the neatpolymers. Obtained from CPM data, spectral dependencesof absorption coefficient were approximated using Gaussiandistribution of density-of-states within HOMO (highestoccupied molecular orbital) and LUMO (lowest unoccupiedmolecular orbital) bands. The approximation procedureallowed us to evaluate rather optical than electricalbandgaps for the studied materials. Moreover, spectra ofpolymer:PC71BM blends were fitted well by the sum of twoGaussian peaks which reveal both the transitions withinthe polymer and the transitions involving charge transferstates at the donor-acceptor interface in the BHJ.

【 授权许可】

Unknown