Study finds CsPbBr₃ out-of-phase perovskite helps highly sensitive X-ray detection

A recent study conducted by the research team at Hefei Institutes of Physical Science of the Chinese Academy of Sciences, has introduced a new method for enhancing X-ray detection by incorporating out-of-phase CsPb₂Br₅ perovskite into CsPbBr₃ bulk material.

"We achieved really good sensitivity for detecting X-rays (2.58×10⁵ μC Gyair-1 cm^-2), and a low detection limit (127.9 nGy_air^-1)," said Prof. Pan Xu, who led the team, "We also integrated this technique with a thin-film transistor (TFT) plate to make X-ray images."

The relevant 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 traditional detectors. Inorganic perovskite CsPbBr₃ has excellent environmental stability and unique high-temperature plasticity, rendering it particularly advantageous for X-ray detector and imaging applications.

However, making single-crystal CsPbBr₃ is difficult and expensive, and polycrystalline CsPbBr₃ devices have low electron mobility, limiting their use in certain imaging systems.

In this study, scientists developed a new method called the Out-of-Phase Articulation Strategy (OPAS). They used OPAS 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 decrease 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 needing a lot of voltage.

In addition, the researchers put together CsPb₂Br₅/CsPbBr₃ on TFT backplanes to realize multi-pixel X-ray surface-array imaging. This proved that CsPbBr₃ material can be used for imaging.

"It also gives us a new material system and design concept for using chalcocite in X-ray imaging," added Ye.

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