Synergistic Effect of Double Lone‐Pair Electrons Cations toward Enhancing X‐ray Detection Performance in Novel Oxide Single Crystals

ABSTRACT Oxide semiconductors are highly promising materials for X‐ray detection applications due to their robust absorption, outstanding physicochemical stability, and excellent crystal growth habits. However, most of them exhibit poor detection performance, limiting their applications in X‐ray imaging. Here, the synergistic effect of double lone‐pair electrons cations is proposed to enhance X‐ray detection of oxide semiconductors. These lone‐pair electrons facilitate the generation of more charge carriers, enhance charge‐carrier mobility, and increase the effective collection of charge carriers, resulting in excellent detection performance. High‐quality Bi 2 Te 2 O 7 with two lone‐pair electron cations (Bi 3+ and Te 4+ ), and Bi 2 Ti 2 O 7 , which contains one (Bi 3+ ), are grown through the flux method. As expected, the Bi 2 Te 2 O 7 crystal exhibits better carrier transport than the Bi 2 Ti 2 O 7 crystal due to the synergistic effect of double lone‐pair electron cations. The Bi 2 Te 2 O 7 crystal detector achieves an ultrahigh sensitivity (1202 µC Gy air ‒1 cm ‒2 ) and an ultralow detection limit (2.71 nGy air s −1 ). At 200°C, its sensitivity increases to 1670 µC Gy air ‒1 cm ‒2 . Additionally, the Bi 2 Te 2 O 7 array detector offers spatial resolution of 2.37 lp mm −1 and performs well in high‐temperature X‐ray imaging. Our work confirms that the synergistic effect of double lone‐pair electrons cations is a highly efficient strategy for enhancing X‐ray detection performance.