Efficient Small-Molecule-Based Inverted Organic Solar Cells With Conjugated Polyelectrolyte as a Cathode Interlayer

Author

Qingduan Li ; Feng Liu ; Xiaowen Hu ; Wenzhan Xu ; Liping Wang ; Xuhui Zhu ; Xiong Gong ; Yong Cao

Author_Institution

State Key Lab. of Luminescent Mater. & Devices, South China Univ. of Technol., Guangzhou, China

Volume

5

Issue

4

fYear

2015

fDate

Jul-15

Firstpage

1118

Lastpage

1124

Abstract

An efficient organic photovoltaics (OPVs) fabricated by using benzofuran-substituted diketopyrrolopyrrole (DPP)-oligothiophene-3,6-bis(5-(benzofuran-2-yl)thiophen-2-yl)-2,5-bis (2-ethylhexyl) pyrrolo[3,4-c] pyrrole-1,4-dione (DPP(TBFu)₂ ) blended with [6,6]-phenyl-C61-butyric acid methyl ester (PC₆₁BM) as the bulk heterojunction composite and a conjugated polyelectrolyte as the electron extraction layer in the inverted device structure is reported. Improved fill factor (FF) but reduced short-circuit current density were obtained from DPP(TBFu)₂ :PC₆₁ BM-based OPVs processed from chloroform solution with small percentage of solvent processing additive, 1,8-diiodooctane (DIO). The investigation by grazing incidence X-ray diffraction and resonant soft X-ray scattering indicated that the large phase separation in the thin film of DPP(TBFu)₂ :PC₆₁ BM BHJ composite was induced by DIO, which results in decreased J_SC.

Keywords

X-ray diffraction; X-ray scattering; current density; electrochemical electrodes; filled polymers; phase separation; polymer blends; polymer electrolytes; polymer films; short-circuit currents; solar cells; thin film devices; 1,8-diiodooctane; [6,6]-phenyl-C61-butyric acid methyl ester; benzofuran-substituted diketopyrrolopyrrole-oligothiophene-3,6-bis(5-(benzofuran-2-yl)thiophen-2-yl)-2,5-bis(2-ethylhexyl) pyrrolo[3,4-c] pyrrole-1,4-dione; bulk heterojunction composite; cathode interlayer; chloroform solution; conjugated polyelectrolyte; electron extraction layer; fill factor; grazing incidence X-ray diffraction; inverted device structure; organic photovoltaics; phase separation; resonant soft X-ray scattering; short-circuit current density; small-molecule-based inverted organic solar cells; solvent processing additive; thin film; Absorption; Annealing; Indium tin oxide; Photovoltaic cells; Photovoltaic systems; Polymers; Interlayer; inverted device structure; organic photovoltaics (OPV); small molecules; solvent processing additive; thin-film morphology;

fLanguage

English

Journal_Title

Photovoltaics, IEEE Journal of

Publisher

ieee

ISSN

2156-3381

Type

jour

DOI

10.1109/JPHOTOV.2015.2425656

Filename

7104066