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

Heetak Han, Sanggeun Lee, Jungmok Seo, Chandreswar Mahata, Sung Hwan Cho, A. Reum Han, Keun Sung Hong, Joon Ho Park, Myung Jin Soh, Cheolmin Park, Taeyoon Lee

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Abstract: Although 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 code: 8.67.Sc

Original languageEnglish
JournalNanoscale Research Letters
Volume9
Issue number1
DOIs
Publication statusPublished - 2014 Dec 1

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Single-walled carbon nanotubes (SWCN)
Polymers
carbon nanotubes
X rays
composite materials
augmentation
Composite materials
polymers
x rays
Photocurrents
Detectors
photocurrents
detectors
Excitons
Signal to noise ratio
signal to noise ratios
excitons
Picture archiving and communication systems
Dark currents
Current voltage characteristics

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics

Cite this

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. / Enhancement of X-ray detection by single-walled carbon nanotube enriched flexible polymer composite. In: Nanoscale Research Letters. 2014 ; Vol. 9, No. 1.
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abstract = "Abstract: Although 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 code: 8.67.Sc",
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Enhancement of X-ray detection by single-walled carbon nanotube enriched flexible polymer composite. / 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.

In: Nanoscale Research Letters, Vol. 9, No. 1, 01.12.2014.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Enhancement of X-ray detection by single-walled carbon nanotube enriched flexible polymer composite

AU - Han, Heetak

AU - Lee, Sanggeun

AU - Seo, Jungmok

AU - Mahata, Chandreswar

AU - Cho, Sung Hwan

AU - Han, A. Reum

AU - Hong, Keun Sung

AU - Park, Joon Ho

AU - Soh, Myung Jin

AU - Park, Cheolmin

AU - Lee, Taeyoon

PY - 2014/12/1

Y1 - 2014/12/1

N2 - Abstract: Although 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 code: 8.67.Sc

AB - Abstract: Although 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 code: 8.67.Sc

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U2 - 10.1186/1556-276X-9-610

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