Fully organic solid state tissue equivalent radiation dose (SSTED) detector (Conference Presentation)

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 Strobele, 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., Basirico, 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.