Heavy metallic oxide nanoparticles for enhanced sensitivity in semiconducting polymer x-ray detectors
Intaniwet, A, Mills, CA, Shkunov, M, Sellin, PJ and Keddie, JL (2012) Heavy metallic oxide nanoparticles for enhanced sensitivity in semiconducting polymer x-ray detectors Nanotechnology, 23 (23). ? - ?. ISSN 0957-4484
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Semiconducting polymers have previously been used as the transduction material in x-ray dosimeters, but these devices have a rather low detection sensitivity because of the low x-ray attenuation efficiency of the organic active layer. Here, we demonstrate a way to overcome this limitation through the introduction of high density nanoparticles having a high atomic number (Z) to increase the x-ray attenuation. Specifically, bismuth oxide (Bi O ) nanoparticles (Z=83 for Bi) are added to a poly(triarylamine) (PTAA) semiconducting polymer in the active layer of an x-ray detector. Scanning electron microscopy (SEM) reveals that the Bi O nanoparticles are reasonably distributed in the PTAA active layer. The reverse bias dc currentvoltage characteristics for PTAABi O diodes (with indium tin oxide (ITO) and Al contacts) have similar leakage currents to ITO/PTAA/Al diodes. Upon irradiation with 17.5keV x-ray beams, a PTAA device containing 60wt% Bi O nanoparticles demonstrates a sensitivity increase of approximately 2.5 times compared to the plain PTAA sensor. These results indicate that the addition of high-Z nanoparticles improves the performance of the dosimeters by increasing the x-ray stopping power of the active volume of the diode. Because the Bi O has a high density, it can be used very efficiently, achieving a high weight fraction with a low volume fraction of nanoparticles. The mechanical flexibility of the polymer is not sacrificed when the inorganic nanoparticles are incorporated. © 2012 IOP Publishing Ltd.
|Divisions :||Faculty of Engineering and Physical Sciences > Physics|
|Identification Number :||10.1088/0957-4484/23/23/235502|
|Additional Information :||Copyright 2012 Institute of Physics. This is the author's accepted manuscript.|
|Depositing User :||Symplectic Elements|
|Date Deposited :||26 Jul 2012 13:42|
|Last Modified :||09 Jun 2014 13:25|
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