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Previous studies have demonstrated the use of crystalline organic semiconductors to detect and localize the passage of charged particles and energetic radiation. [1-6] In this context, polycrystalline bis-(triisopropylsilylethynyl)pentacene (TIPS-pentacene) was printed onto polyethylene naphthalate (PEN) substrates patterned with parylene-C dielectric, PEDOT electrodes and gold pads to form fully organic flexible x-ray detectors. The electrodes were patterned using orthogonal photolithography and oxygen reactive ion etching to define a width/length (W/L) = 100 µm/10 µm. An organic voltage divider built using these materials was hot bar bonded to a printed circuit board (PCB) via a flexible conducting tape to form a complete sensor system. The devices were irradiated with a variety of localized and large area sources and the output was extracted from the node between the two resistors and then connected to an operational amplifier via a second PCB. Dark currents for each resistor were in the 100 pA - 1 nA range. The device demonstrated has the potential to be applied in microdosimetry to allow for detection using a cross-section that matches organic tissue forming a solid state tissue equivalent detector (SSTED) [7].
References:
[1] Beckerle, P. and Ströbele, H., 2000. Charged particle detection in organic semiconductors. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 449(1-2), pp.302-310.
[2] Fraboni, B., Ciavatti, A., Merlo, F., Pasquini, L., Cavallini, A., Quaranta, A., Bonfiglio, A. and Fraleoni‐Morgera, A., 2012. Organic Semiconducting Single Crystals as Next Generation of Low‐Cost, Room‐Temperature Electrical X‐ray [3] Detectors. Advanced Materials, 24(17), pp.2289-2293.
Intaniwet, A., Keddie, J.L., Shkunov, M. and Sellin, P.J., 2011. High charge-carrier mobilities in blends of poly (triarylamine) and TIPS-pentacene leading to better performing X-ray sensors. Organic Electronics, 12(11), pp.1903-1908.
[4] Kane, M.C., Lascola, R.J. and Clark, E.A., 2010. Investigation on the effects of beta and gamma irradiation on conducting polymers for sensor applications. Radiation Physics and Chemistry, 79(12), pp.1189-1195..
[5] Lai, S., Cosseddu, P., Basiricò, L., Ciavatti, A., Fraboni, B. and Bonfiglio, A., 2017. A Highly Sensitive, Direct X‐Ray Detector Based on a Low‐Voltage Organic Field‐Effect Transistor. Advanced Electronic Materials, 3(8), p.1600409.
[6] Schrote, K. and Frey, M.W., 2013. Effect of irradiation on poly (3, 4-ethylenedioxythiophene): poly (styrenesulfonate) nanofiber conductivity. Polymer, 54(2), pp.737-742.
[7] Bardash, M., 2010, August. An organic semiconductor device for detecting ionizing radiation on a cellular level. In Organic Semiconductors in Sensors and Bioelectronics III (Vol. 7779, p. 77790F). International Society for Optics and Photonics.
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