Photocurrent transients in polymer-fullerene bulk heterojunction organic solar cells

Author

Li, Lijun ; Li, Kejia ; Khlyabich, Petr P. ; Burkhart, Beate ; Thompson, Barry C. ; Campbell, Joe C.

Author_Institution

Dept. of Electr. & Comput. Eng., Univ. of Virginia, Charlottesville, VA, USA

fYear

2012

fDate

3-8 June 2012

Abstract

By measuring the transient photocurrents we study the charge carrier dynamics in regioregular poly(3-hexylthiophene) (P3HT): 6,6-phenyl-C61-butyric acid methyl ester (PCBM), and poly(3-hexylthiophene) thiophene thienopyrazine (P3HTT-TP):PCBM bulk heterojunction (BHJ) solar cells. The latter is based on a novel “semi-random” copolymer and exhibits broad spectral absorption. We observe that the charge carrier transport in P3HTT-TP:PCBM is more imbalanced than that of P3HT:PCBM. Voltage dependent photocurrent transients indicate that P3HT:PCBM has longer carrier lifetimes than P3HTT-TP:PCBM. Light intensity dependent open-circuit voltage measurements show stronger monomolecular recombination in P3HTT-TP:PCBM. The unfavorable charge carrier transport may be one of the reasons for the low power conversion efficiency of P3HTT-TP:PCBM BHJ solar cells.

Keywords

photoconductivity; solar cells; (P3HTT-TP):P CBM bulk heterojunction solar cells; 6,6-phenyl-C61-butyric acid methyl ester; P3HTT-TP:P CBM BHJ solar cells; charge carrier dynamics; charge carrier transport; light intensity dependent open-circuit voltage measurements; low power conversion efficiency; photocurrent transients; poly(3-hexylthiophene) thiophene thienopyrazine; polymer-fullerene bulk heterojunction organic solar cells; regioregular poly(3-hexylthiophene); transient photocurrents; voltage dependent photocurrent transients; Charge carriers; Heterojunctions; Photoconductivity; Photovoltaic cells; Polymers; Power conversion; Transient analysis; charge carrier lifetime; organic semiconductors; photovoltaic cells; polymer films;

fLanguage

English

Publisher

ieee

Conference_Titel

Photovoltaic Specialists Conference (PVSC), 2012 38th IEEE

Conference_Location

Austin, TX

ISSN

0160-8371

Print_ISBN

978-1-4673-0064-3

Type

conf

DOI

10.1109/PVSC.2012.6318164

Filename

6318164