Researchers at the Hefei Institutes of Physical Science of the Chinese Academy of Sciences have proposed a new method to enhance X-ray detection by incorporating out-of-phase CsPb₂Br₅ perovskite into CsPbBr₃ bulk material. 

They achieved good sensitivity for X-ray detection and a low detection limit, and integrated this technique with a thin-film transistor (TFT) plate to produce X-ray images. 

The results were published in Advanced Functional Materials. 

Metal halide perovskite is a promising material for detecting things like X-rays, offering better sensitivity and resolution than conventional detectors. Inorganic perovskite CsPbBr₃ has excellent environmental stability and unique high-temperature plasticity, making it particularly advantageous for X-ray detection and imaging applications. However, single-crystal CsPbBr₃ is difficult and expensive to produce, and polycrystalline CsPbBr₃ devices have low electron mobility, limiting their use in certain imaging systems. 

In this study, the researchers developed a new method called, the out-of-phase articulation strategy, to combine a special material called CsPb₂Br₅ with another material called CsPbBr₃. They made a mixture of these materials using a technique called high-energy mechanical ball milling.  

Adding CsPb₂Br₅ didn't slow down the current baseline. Instead, it helped to speed up the movement of electrons and holes, which are important for detecting X-rays.  

This improvement was possible because CsPb₂Br₅ created pathways for the electrons and holes to move more easily within CsPbBr₃. Using this method, they achieved high sensitivity and spatial resolution for detecting X-rays without the need for high voltage. 

In addition, the researchers assembled CsPb₂Br₅/CsPbBr₃ on TFT backplanes to realize multi-pixel X-ray surface array imaging. This proved that the CsPbBr₃ material could be used for imaging. It also offers a new material system and design concept for using chalcocite in X-ray imaging. 

This work shows that perovskites with the introduction of a 2D phase exhibit a carrier transport effect and good long-term stability, making them promising candidates for commercial use.

The introduction of CsPb₂Br₅ enhances the transport of charge carriers within CsPbBr₃. (Image by WAN Changmao)