Purely organic 4HCB single crystals exhibiting high hole mobility for direct detection of ultralow-dose X-radiation. Issue 10 (26th February 2020)

• Record Type: Journal Article
• Authors: Zhao, Dou; Xu, Meng; Xiao, Bao; Zhang, Binbin; Yan, Lei; Zeng, Guoqiang; Dubois, Alain; Sellin, Paul; Jie, Wanqi; Xu, Yadong
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 10(2020)
• Page Start: 5217
• Page End: 5226
• Publication Date: 2020-02-26
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c9ta12817d
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Purely organic 4HCB single crystals show a capability of directly detecting 241 Am 5.49 MeV α particles and X-ray imaging under low-dose rate (below 50 μGyair s −1 ) exposure conditions. Abstract : Precise detection of low-dose X-radiation using purely organic direct detectors is vital for tissue-equivalent dosimeters and safety control in medical radiation treatment, but it still remains a challenge. Here, we report a promising organic radiation detector based on 4-hydroxycyanobenzene (4HCB, C7 H5 NO) single crystals. Plate-like 4HCB single crystals up to 18 × 15 × 1.2 mm 3 in size are obtained by an optimized solvent evaporation method, thanks to the clarification of the two-dimensional nucleation growth mechanism. After post surface treatment, the leakage current of the 4HCB detector is no larger than 0.1 pA under an electric field of 600 V cm −1 . The fabricated detectors show a capability of detecting 241 Am 5.49 MeV α particles with a well resolved full energy peak. The calculated hole mobility ( μ h ) and hole mobility lifetime product ( μτ )h are 3.40 cm 2 V −1 s −1 and 8.50 × 10 −5 cm 2 V −1, respectively. Simultaneously, under a 50 kVp X-ray beam, a detection limit as low as 0.29 μGyair s −1 with a high sensitivity of 10 μC Gyair −1 cm −2 is achieved in the bias range of 40–100 V, contributing to a superior X-ray imaging capability with a spatial resolution of 0.9 lp mm −1 at a low-dose rate (below 150 μGyair s −1 ) of exposure.