Performance of High Spatial Resolution Hybrid and All-Inorganic Perovskite Direct X-Ray Imagers: A Comparative Study

This paper presents a systematic comparative study of solution-processed hybrid organicinorganic and all-inorganic perovskite-based X-ray imagers (PeroXIs) integrated onto identical active pixel arrays. Methylammonium lead iodide (MAPI) and cesium lead bromide (CPB) films were fabricated via blade-coating and characterized for direct conversion X-ray detection performance. The CPB-based imagers demonstrated markedly superior performance, achieving spatial resolution of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$6.9 \text{lp} / \text{mm}$</tex> at 20\% modulation transfer function compared to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$5.5 \text{lp} / \text{mm}$</tex> for MAPI-based devices, while maintaining a significantly higher contrast-to-noise ratio of 442 versus typical values of 11-147 for MAPI-based systems. Mobility-lifetime <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mu \tau)$</tex> product measurements revealed values of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$8.0 \times 10^{-4} \text{cm}^{2} / \mathrm{V}$</tex> for CPB versus <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.3 \times 10^{-4} \text{cm}^{2} / \mathrm{V}$</tex> for MAPI, correlating with superior charge collection efficiency at equivalent electric fields. CPB-based detectors exhibited exceptional sensitivity of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$55,400 \mu \mathrm{C}$</tex> Gyair <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$^{-1} \text{cm}^{-2}$</tex>, approximately four times higher than MAPI counterparts, with a remarkably low detection limit of 417 pGyair <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{s}^{-1}$</tex>. The all-inorganic devices also demonstrated enhanced operational stability with sensitivity variations below <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 1 \%$</tex> over eight months without encapsulation, compared to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 4 \%$</tex> for encapsulated MAPI devices. Integration with high-density <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$7.8 \mu \mathrm{m}$</tex> pixel arrays enabled unprecedented spatial resolution exceeding <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$20 \text{lp} / \text{mm}$</tex> while maintaining high detection efficiency ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\operatorname{DQE}(0) \approx 85.3 \%$</tex>), effectively resolving the longstanding trade-off between spatial resolution and detection efficiency in X-ray imaging. These results establish solution-processed inorganic perovskites as a scalable, high-performance platform capable of surpassing commercial standards for low-dose, high-resolution X-ray imaging across medical, industrial, and scientific domains.