Near-Room-Temperature Solution Epitaxy of Large-Area High-Mobility Two-Dimensional Organic Single Crystals for Direct X-Ray Detection

Abstract

The fundamental trade-off between high intrinsic carrier mobility and solution processability severely limits the development of organic single crystals (OSCs). For instance, while 2,6-diphenylanthracene (DPA) is a benchmark candidate for direct X-ray detection, its intrinsic insolubility hinders solution processing, and conventional solubilizing alkyl modifications inevitably degrade transport efficiency. Here, we report a facile surfactant-assisted near-room-temperature solution epitaxy method to overcome this bottleneck, fabricating centimeter-scale ultrathin DPA two-dimensional (2D) OSCs utilizing a common solvent at 35°C. Electrical characterization reveals that the as-fabricated DPA 2DOSCs exhibit a maximum mobility of 5.55 cm²/(V∙s), an order of magnitude higher than that of the alkylated C₆-DPA counterpart. This superior charge transport efficiency directly translates into exceptional X-ray detection performance, achieving a high sensitivity of 7.02×10³ μC/(Gy∙cm²) and a low detection limit of 24.05 nGy/s. This work not only provides a facile low-energy route to process intrinsically insoluble organic semiconductors but also establishes high-mobility DPA 2DOSCs as a premier platform for next-generation large-area organic direct X-ray detectors.

Keywords

high mobility / organic single crystals / solution epitaxy methods / X-ray detectors

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