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ground-breaking PEROvskite technologies for advanced X-ray medical Imaging Systems

Periodic Reporting for period 1 - PEROXIS (ground-breaking PEROvskite technologies for advanced X-ray medical Imaging Systems)

Reporting period: 2020-01-01 to 2021-06-30

The aim of the PEROXIS project is to develop a groundbreaking direct X-ray detection technology to be introduced into imaging system with higher sensitivity and spatial resolution compared to conventional ones. These will support diagnosis during intervention and treatments of various diseases such as cardiovascular disease (CVD) and chronic obstructive pulmonary disease (COPD) which are respectively the first leading cause and the third leading cause of death globally.
The medical sector will be highly impacted by the PEROXIS project outcome: future applications of an improved PEROXIS imaging system will not be limited to COPD and CVD only, but may be extended to various other clinical domains in which the performance of diagnostic driven therapy systems is limited by current flat panel X-ray detector technology.
The emerging semiconducting perovskite materials, largely used for photovoltaic applications, are a good candidate since they have the potential to globally address the following PEROXIS ambitious objectives:
-Advancing X-ray based imaging systems for advanced diagnostics and treatments of two major diseases: cardiovascular disease (CVD) and chronic obstructive pulmonary disease (COPD)
-Improving the efficiency and spatial resolution of flat panel X-ray detectors
-Groundbreaking perovskite-based direct conversion X-ray imaging detectors for large-area compatibility
-Validating the feasibility of phase contrast imaging for earlier detection of chronic obstructive pulmonary disease

To develop a ground-breaking and cost-effective technology for the direct conversion of X-rays into electronic charges by using thick (>500µm) semi-conducting hybrid organic inorganic perovskite layers, The PEROXIS project will consider two complementary deposition processes compatible with large area X-ray flat panels:
• The short-term and low-risk “powder sintering route” to improve the performance and robustness of the current process and upscale it from small area to large area prototype detectors,
• The medium term “solution-process route” to obtain much higher optoelectronic performances through denser and higher crystallinity perovskite layers compared to powder sintering, and upscaled to small area demonstrators
The definition of the high level system requirements has been peformed for the two different investigational devices that will be used for the evaluation of the perovskite direct X-ray detection technology for cardiovascular disease (CCVD) and chronic obstructive pulmonary disease (COPD).

The two first milestones of the project have been passed:
- For the powder sintering route, the frontplane process has been demonstrated on 5x5 cm² size devices
- For the solution-process route, a growth reactor developed for 5x5 cm² active matrixes is operational.

For the powder sintering approach, image measurements on medium size devices (5x5 cm²) show performance in spatial resolution, linearity, sensitivity, signal lag and long term stability which allow to assess that perovskite detectors have the potential to outperform the existing direct conversion detectors based on amorphous selenium.
For the solution process approach, freestanding single devices have been achieved for advanced characterization.

Advanced electronic characterization methods such as impedance spectroscopy and transient techniques have been used to measure the electrical response of single diode devices from both processes. This allowed to gain fundamental knowledge on the connection between device architecture (absorbing perovskite layer structure, contacting electrodes...) and operational mechanisms and device physics of X-ray detectors. These results have been described into two publications.

The development and the sourcing of detector components, especially the key components corresponding to the TFT arrays for the different imaging test vehicles, have been achieved for further steps in the detectors maunfacturing process.

For phase contrast imaging purpose, physical limits of spatial resolution on perovskite layers have been calculated and characterization of first samples have been conducted.
Progress beyond the State of the Art:
The powder sintering and the solution approaches are complementary and will be conducted in parallel, as shown in the PEROXIS qualitative innovation S-curve.
On the one hand, the powder sintering approach has the potential to reach in a short timeframe the targeted specifications of detector efficiency and accuracy, mandatory to improve the treatment of CVD and early diagnosis of COPD.
On the other hand, the solution process approach is a less mature and more risky concept, but with a higher performance potential. In particular, the charge carrier mobility and lifetime could be improved by two orders of magnitude compared to the powder sintering approach.

Expected potential Impact:
PEROXIS will enable better image quality and dose reduction for CVD as well as early diagnosis of COPD, together with a cost effective solution for the detector within an X-ray medical imaging system.
This should allow a substantial gain in competitiveness compared to the current technologies, thus strengthen European medical imaging industry and expect business growth by increased market share in X-ray systems and detectors.
Population screening increase, saving or improving several million people lives per year as well as reduced global healthcare costs are expected.
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