Near-infrared photoresponse in single walled carbon nanotube/polymer composite films

TL;DR

This study investigates the near-infrared photoresponse of SWCNT/polymer composite films, revealing significantly enhanced photoresponse compared to pure SWCNT films, with dependence on SWCNT loading and laser position, explained by exciton dissociation at interfaces.

Contribution

It demonstrates enhanced near-infrared photoresponse in SWCNT/polymer composites and elucidates the role of interfaces and loading ratios in photoresponse behavior.

Findings

Photoresponse up to 157% in composites versus 40% in pure SWCNT films.

Maximum photocurrent occurs at the metal-film interface.

Photoresponse driven by exciton dissociation and charge separation at Schottky barriers.

Abstract

We present a near-infrared photoresponse study of single-walled carbon nanotube/poly(3-hexylthiophene)-block-polystyrene polymer (SWCNT/P3HT-b-PS) composite films for different loading ratios of SWCNT in the polymer matrix. Compared to the pure SWCNT film, the photoresponse [(light current - dark current)/dark current] is much larger in the SWCNT/polymer composite films. The photoresponse is up to 157% when SWCNTs are embedded in P3HT-b-PS while for a pure SWCNT film it is only 40%. We also show that the photocurrent strongly depends on the position of the laser spot with maximum photocurrent occurring at the metal-film interface. We explain the photoresponse due to exciton dissociations and charge carrier separation caused by a Schottky barrier at the metallic electrode - SWCNT interface