Enhancement of X-ray detection by single-walled carbon nanotube enriched flexible polymer composite.

Content Provider	Europe PMC
Author	Han, Heetak Lee, Sanggeun Seo, Jungmok Mahata, Chandreswar Cho, Sung Hwan Han, A-Reum Hong, Keun-Sung Park, Joon-Ho Soh, Myung-Jin Park, Cheolmin Lee, Taeyoon
Abstract	AbstractAlthough organic-based direct conversion X-ray detectors have been developed, their photocurrent generation efficiency has been limited by recombination of excitons due to the intrinsically poor electrical properties of organic materials. In this report, we fabricated a polymer-based flexible X-ray detector and enhanced the X-ray detection sensitivity using a single-walled carbon nanotube (SWNT) enriched polymer composite. When this SWNT enriched polymer composite was used as the active layer of an X-ray detector, it efficiently separated charges at the interface between the SWNTs and polymer, preventing recombination of X-ray-induced excitons. This increased the photocurrent generation efficiency, as measured from current-voltage characteristics. Therefore, X-ray-induced photocurrent and X-ray detection sensitivity were enhanced as the concentration of SWNTs in the composite was increased. However, this benefit was counterbalanced by the slow and unstable time-dependent response at high SWNT concentrations, arising from reduced Schottky barrier heights between the active layer and electrodes. At high SWNT concentration, the dark current also increased due to the reduced Schottky barrier height, leading to decrease the signal-to-noise ratio (SNR) of the device. Experimental results indicated that 0.005 wt.% SWNT in the composite was the optimum composition for practical X-ray detector operation because it showed enhanced performance in both sensitivity and SNR. In mechanical flexibility tests, the device exhibited a stable response up to a bending radius of 0.5 cm, and the device had no noticeable change in diode current after 1,000 bending cycles.PACS code8.67.ScElectronic supplementary materialThe online version of this article (doi:10.1186/1556-276X-9-610) contains supplementary material, which is available to authorized users.
ISSN	19317573
Journal	Nanoscale Research Letters
Volume Number	9
PubMed Central reference number	PMC4493992
Issue Number	1
PubMed reference number	26088997
e-ISSN	1556276X
DOI	10.1186/1556-276x-9-610
Language	English
Publisher	Springer
Publisher Date	2014-11-12
Publisher Place	New York
Access Restriction	Open
Rights License	This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. © Han et al.; licensee Springer. 2014
Subject Keyword	Semiconducting polymers X-ray detectors Single-walled carbon nanotubes Flexible electronics
Content Type	Text
Resource Type	Article
Subject	Nanoscience and Nanotechnology Condensed Matter Physics Materials Science