Trap States Ruling Photoconductive Gain in Tissue-Equivalent, Printed Organic X-Ray Detectors

Ilaria Fratelli, Laura Basiricò, Andrea Ciavatti, Zachary A. Lamport, John E. Anthony, Ioannis Kymissis, Beatrice Fraboni

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Organic semiconductors are excellent candidates for X-ray detectors that can adapt to new applications, with unique properties including mechanical flexibility and the ability to cover large surfaces. Their chemical composition, primarily carbon and hydrogen, makes them human tissue equivalent in terms of radiation absorption. This is a highly desirable property for a radiation dosimeter to be employed in medical diagnostics and therapy, however a low-Z composition limits the absorption of ionizing radiation. The detection efficiency can be enhanced by considering the photoconductive gain (PG) effect, a significant contributor to the ionizing radiation detection mechanism in this class of materials. In this work, a process of controlled solution deposition by nozzle printing and crystallization of an organic semiconductor thin film is demonstrated whereby a flexible, arrayed thin-film X-ray detector with record X-ray sensitivities among flexible radiation detectors (S = (9.0 ± 0.4) × 107 µC Gy−1 cm−3) is developed. The excitonic peaks responsible for the activation of the PG effect are investigated and identified using a novel technique called photocurrent spectroscopy optical quenching, and the analysis of the changes in trap states is further demonstrated.

Original languageEnglish
Article number2200769
JournalAdvanced Materials Technologies
Volume8
Issue number3
DOIs
StatePublished - Feb 10 2023

Bibliographical note

Publisher Copyright:
© 2022 The Authors. Advanced Materials Technologies published by Wiley-VCH GmbH.

Keywords

  • flexible electronics
  • organic direct X-ray detectors
  • organic thin-film transistors
  • photoconductive gain
  • printing

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Industrial and Manufacturing Engineering

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