Perovskite X-ray Photon Counting Detector
Lead Research Organisation:
UNIVERSITY OF CAMBRIDGE
Department Name: Chemical Engineering and Biotechnology
Abstract
Perovskite X-ray Photon Counting Detectors (PePAD) project focuses on the development of multi-pixelated photon counting detectors (PCDs) via growing high-quality perovskite (PVK) single crystals directly onto pixelated application-specific integrated circuit (ASIC) arrays, thus realising the first pixelated PVK-based PCDs. The PePAD is an ambitious project comprised of the following objectives.
Objective 1: Modular and shape-controlled growth of PVK single crystals onto device-relevant substrates with optoelectronic properties rivalling to conventional Cadmium Telluride (CdTe) or Cadmium Zinc Telluride (CZT) semiconductors. WP1 will first allow fabricating PVK single crystals via inverse temperature crystallisation (ITC) method. The levers to optimise the PVK single crystals growth will include tuning fractions of A-site cations (FA, Cs and/or MA) and additives in the crystal growth including EDTA will be used inspired by the host group's recent work.
Objective 2: Fabrication and build a strong fundamental understanding of single-pixel PCD with self-operating capability (at 0V applied bias), low dark current, high energy resolution and stable operation. WP2 will allow optimisation of device architecture and their components. The general structure of single-pixel PCD will be a Me/HTL/PVK single crystal/ETL/Me or TCO. Interfaces will be optimised to best address the defects arising at the interfaces of PVK and ETL or HTL, including use of 2D/3D surfaces, LiF and/or MgF2 thin layers inspired by PV works.
Objective 3: Fabrication and demonstration of high-performance pixelated PCD with low charge sharing and low pixel-to-pixel leakage current, without pulse pileup effect at certain fluxes and high image resolution. WP3 will allow demonstration of PVK single crystal growth already optimised in WP1 directly on the ASIC arrays. The optimized charge transport layers and electrodes in WP2 will be deposited on the PVK single crystals to complete multi-pixel PCDs.
Objective 1: Modular and shape-controlled growth of PVK single crystals onto device-relevant substrates with optoelectronic properties rivalling to conventional Cadmium Telluride (CdTe) or Cadmium Zinc Telluride (CZT) semiconductors. WP1 will first allow fabricating PVK single crystals via inverse temperature crystallisation (ITC) method. The levers to optimise the PVK single crystals growth will include tuning fractions of A-site cations (FA, Cs and/or MA) and additives in the crystal growth including EDTA will be used inspired by the host group's recent work.
Objective 2: Fabrication and build a strong fundamental understanding of single-pixel PCD with self-operating capability (at 0V applied bias), low dark current, high energy resolution and stable operation. WP2 will allow optimisation of device architecture and their components. The general structure of single-pixel PCD will be a Me/HTL/PVK single crystal/ETL/Me or TCO. Interfaces will be optimised to best address the defects arising at the interfaces of PVK and ETL or HTL, including use of 2D/3D surfaces, LiF and/or MgF2 thin layers inspired by PV works.
Objective 3: Fabrication and demonstration of high-performance pixelated PCD with low charge sharing and low pixel-to-pixel leakage current, without pulse pileup effect at certain fluxes and high image resolution. WP3 will allow demonstration of PVK single crystal growth already optimised in WP1 directly on the ASIC arrays. The optimized charge transport layers and electrodes in WP2 will be deposited on the PVK single crystals to complete multi-pixel PCDs.
Publications
| Description | This research brings significant advancements in the development of a new type of X-ray detector. We successfully created high-quality perovskite semiconductor crystals and using these crystals, we built an X-ray detector. Our X-ray detector successfully detected extremely low doses of X-ray radiation including individual X-ray photons, which is crucial for much lower radiation exposure, improving safety for patients undergoing medical scans. We are also developing a more advanced version of our detector with multiple pixels, similar to the tiny squares in a camera sensor. This design could lead to improved imaging devices for healthcare, security screening, and industrial inspection, benefiting society by enabling safer and more accurate X-ray imaging solutions. This breakthrough shows promise for transforming medical imaging by reducing radiation risks and improving image quality. |
| Exploitation Route | Our research outcomes have potential applications in medical imaging, security screening, and industrial inspection. The developed X-ray detector can improve image quality while reducing radiation exposure, enhancing patient safety and screening efficiency. Medical equipment manufacturers, security providers, and industry experts can adopt and develop this technology. Academic researchers can further refine crystal growth techniques and device performance to expand its potential use. |
| Sectors | Aerospace Defence and Marine Electronics Healthcare |
| URL | https://ieeexplore.ieee.org/abstract/document/10656002 |
| Description | STFC-UKRI Project Partner |
| Organisation | Rutherford Appleton Laboratory |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | During this collaboration, we have successfully fabricated thick perovskite films devices, and developed a single-pixel detector. We have initially assessed their performances and single crystal-based devices have proven a better performance with very low dark currents of <0.001nA/cm2 and a reasonably good detection limit of 167 nGy(air)/s at 1000mV. Now, we aim for developing chips based on these devices and test their performance in collaboration with STFC. |
| Collaborator Contribution | STFC is contributing to the optimization of devices and their architecture. This is an iterative process in which we are also testing the performance of materials in its facilities. The complete iterative process implies synthesizing samples, producing devices, testing their performances both in our in-house equipments and in the STFC facilities. In addition, STFC is contributing to its know-how to produce photon counting ASICs chips, providing us with some, helping in the integration of the device and evaluating its performance. |
| Impact | We have successfully fabricated thick perovskite films based devices and measure their performance. We have also developed a backup approach for high quality perovskites single crystals, and integrate them into devices with better performances. We are currently in the process of optimising chips based on these approaches and we aim for producing a multi-pixel single photon counting detector. |
| Start Year | 2022 |