Proceedings of Asia-Pacific Conference on Perovskite, Organic Photovoltaics&Optoelectronics (IPEROP25)
Publication date: 17th October 2024
Currently, there is a significant need to increase the spatial resolution of medical X-ray imaging while maintaining high detection efficiency to provide high-quality images at low radiation doses [1]. This pushes research for the development of novel detector materials and architectures. Besides diverse state-of-the-art detector materials such as Si a-Se, and CdTe, recently, a novel class of semiconductors - metal halide perovskites - emerged as promising materials for radiography and computed tomography applications. However, existing studies lack persuasive examples of fully integrated perovskite detectors that would combine a high spatial resolution of multi-pixel detectors together with high detection efficiency (DE) [2], for which direct integration of single crystals on the readout substrates would be required. Here we show a method of fabricating high-quality, thick large-grain polycrystalline CsPbBr3 films by melt growth directly on pixelated glass interposers. The obtained detector arrays show a remarkable 20 lp mm-1 spatial resolution with a DE of 75.4% and low noise equivalent dose (NED) of ca. 28 photons for 22 keV X-rays under a low reverse bias voltage. The combination of these characteristics results in unprecedently, for charge-integrating mode, high values of 20% for detective quantum efficiency (DQE) at the Nyquist frequency. Single-pixel devices demonstrate single-photon counting performance for γ-radiation with an energy-resolved peak of 241Am. Melt-grown CsPbBr3 films, featuring a unique combination of detection efficiency, scalable fabrication, and cost-effectiveness, are promising for the development of high spatial resolution, low-dose X-ray imaging systems.
This work was financially supported by the Swiss Innovation Agency (Innosuisse) under grant agreement 46894.1 IP-ENG and by ETH Zürich through the ETH+ Project SynMatLab: Laboratory for Multiscale Materials Synthesis.