Toward next-generation X-ray imaging: Pb-free PErovskite Charge Transport engineering

X-rays are widely applied in medical diagnostics, security screening and scientific research. The growing demand for X-ray imaging has increased the frequency with which humans are exposed to ionizing X-rays, directly increasing radiation-related health risks. To minimize these health risks, X-PECT aims to rationally design materials that enable more sensitive X-ray detectors, thus allowing the use of lower operational radiation doses. Metal halide perovskite (MHP) semiconductors have emerged as a highly promising material class for sensitive X-ray detection. Besides their easy processing, the popularity of MHPs arises from their outstanding optoelectronic properties, such as strong high-energy X-ray absorption, and efficient charge carrier generation and transport, outperforming current market standards. However, the intrinsic instability and toxicity of popular lead-based MHPs hinders their large-scale application in sustainable X-ray technology. X-PECT aims for a fundamental understanding of the intrinsic strengths and limitations of MHPs as photoactive material for X-ray detection. In this context, X-PECT will address urging scientific hurdles related to toxicity, structural and chemical stability, intrinsic charge carrier transport efficiency, and processing efforts. The ultimate goal of X-PECT is to rationally develop highly sensitive, sustainable lead-free MHPs through micromanaging their electronic structure by composition and dimensionality engineering. Tailoring their functionality will be guided by applying a full arsenal of both established characterization techniques and unique (micro)spectroscopy platforms for the full assessment of the structural and photophysical properties to identify and suppress the factor(s) currently limiting the X-ray sensitivity and stability. Ultimately, selected candidate materials will be processed into a stable, scalable pixelated X-ray demonstrator device with a 20- to 50-fold improved sensitivity and resolution.