Microstructural stiffness engineering of low dimensional metal halide perovskites for efficient X-ray imaging

Area of Science:

• Materials Science
• Solid-State Physics
• Optoelectronics

Background:

• Low-dimensional metal halide perovskites (MHPs) exhibit strong exciton-phonon coupling and localization due to their soft lattice.
• Microstructural stiffness engineering is crucial for tuning material properties, yet its impact on MHP luminescence is not well understood.

Purpose of the Study:

• To investigate the effects of microstructural stiffness engineering on the luminescence properties of low-dimensional MHPs.
• To enhance the X-ray excited luminescence (XEL) and photoluminescence quantum yield (PLQY) of MHPs through stiffness modulation.

Main Methods:

• Engineered microstructural stiffness of MHPs via halogen replacement in Ag-X bonds and [AgX4]3- units (X = Br, Cl).
• Increased Young's modulus from 15.6 to 18.3 GPa.
• Utilized spectroscopic analysis and projected crystal orbital Hamilton population calculations.

Main Results:

• Achieved a 10-fold enhancement in XEL intensity and a 16-fold increase in PLQY (from 2.8% to 44.3%).
• Demonstrated that high stiffness in Rb2AgCl3 facilitates radiative pathways and reduces non-radiative transitions.
• Showcased superior anti-deformation ability and enhanced radiation resistance in Rb2AgCl3 due to shorter Ag-Cl bonds.

Conclusions:

• Stiffness engineering is an effective strategy for designing efficient emitters in low-dimensional MHPs.
• Developed a high-performance scintillation screen (Rb2AgCl3@PDMS) with zero self-absorption, ultra-low detection limit, and high resolution.
• The findings offer a new avenue for optimizing MHP-based X-ray detectors and imaging technologies.