High-performance direct detection of α-particle and X-ray with centimeter-sized organic BPEA single crystals

Organic semiconductor single crystals with tissue-equivalent properties present promising advantages for detecting ionizing radiation, particularly X-rays. However, few organic semiconductor materials can exhibit excellent radiation detection performance. In this study, we focus on 9,10-bis(phenylethynyl)anthracene (BPEA) single crystals with two different crystalline phases (α-BPEA and β-BPEA). A slow solution evaporation method is employed to grow centimeter-sized α-BPEA and β-BPEA crystals with high quality. The sandwich-type α-BPEA detector demonstrates exceptional ionizing radiation detection capabilities, with resistivity of 2.72 × 10¹² Ω cm and hole mobility of 2.93 cm² V⁻¹ s⁻¹. The α-BPEA detector also achieves rapid detection of 5.49 MeV α-particles with detection time of 7 ms. The energy resolution and hole mobility-lifetime product are calculated to be 29.93 % and 2.51 × 10⁻⁵ cm² V⁻¹, respectively, marking the best α-particle energy spectrum performance among current organic semiconductor detectors. The α-BPEA detector exhibits X-ray detection sensitivity as high as 451.37 μC Gy_air⁻¹ cm⁻² and detection of limit as low as 26.28 nGy_air s⁻¹. The α-BPEA detector also demonstrates good operational stability and outstanding imaging capabilities, achieving a spatial resolution of 1.6 lp mm⁻¹. The BPEA single crystals suggest significant potential for direct ionizing radiation detection and broader optoelectronic applications.