Trap-limited carrier recombination in single-walled carbon nanotube heterojunctions with fullerene acceptor layers

Andrew J. Ferguson, Anne Marie Dowgiallo, Dominick J. Bindl, Kevin S. Mistry, Obadiah G. Reid, Nikos Kopidakis, Michael S. Arnold, Jeffrey L. Blackburn

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

Single-walled carbon nanotube (SWCNT)-fullerene (C60) bilayers represent an attractive "donor-acceptor" binary system for solar photoconversion, where the kinetics of photoinduced processes depend critically on the properties of the interface between the two materials. Using photoconductivity measurements we identify the kinetic scheme that describes the free carrier kinetics in such bilayers where the dominant SWCNT species is the (7,5) semiconducting nanotube. Following charge separation, the carrier kinetics, covering up to four orders of magnitude in volumetric hole density, are described by a recombination process that is limited by capture and emission at traps or states at the SWCNT-C60 interface. The high-frequency mobility of holes in the (7,5) SWCNT phase is lower than in multichiral films, potentially due to differences in SWCNT defect density for nanotubes that have been purified more aggressively. The results obtained here provide fundamental insights into the transport and recombination of both charges and excitons within SWCNT thin films and bilayers, and point to several potential ways to improve SWCNT-C60 photovoltaic devices.

Original languageEnglish
Article number245311
Pages (from-to)245311-1-245311-8
Number of pages8
JournalPhysical Review B: Condensed Matter and Materials Physics
Volume91
Issue number24
DOIs
Publication statusPublished - 26 Jun 2015
Externally publishedYes

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