Pressure sensors are ubiquitous companions in the Internet of Things for recording system properties. Challenges for current technologies are long-term stability and operation at elevated temperatures >250°C. These challenges are being addressed by the BMBF-funded consortium “QInd – Quantum Sensors for Industrial Applications in Process Technology”, which is part of the QSens future cluster. The CiS Research Institute cooperates closely with the industrial partner Endress+Hauser and provides support with its own expertise in packaging and assembly (AVT) and the characterization of diamond-based materials. Basic research has revealed correlations between mechanical stress and the optical photoluminescence properties of nitrogen vacancy centers (NV centers). What is attractive about this quantum material is its stability over large temperature and pressure ranges and the possibility of achieving purely optically based readout. The project will assess the suitability of NV centers in diamond for pressure measurement in terms of
- the signal strength and the signal-to-noise ratio,
- suitable diamond materials and their availability and
- the process control (industrialization) and the expected costs.
The aim is not necessarily to increase the technology readiness level (TRL), but to improve the level of knowledge of quantum sensor technology for pressure measurement and to limit parasitic influencing variables.
The CiS Research Institute has used cost-efficient diamond materials and bonded them to ceramic measuring cells using industry-typical processes. If these measuring cells are exposed to different pressures, an inner membrane deforms. As a result of this slight deformation, mechanical stresses are transferred to the diamond platelet placed on top. These can be read purely optically using spectroscopic methods or with the aid of microwave-assisted measurements of photoluminescence intensity. It has now been demonstrated that both the packaging + assembly and the two readout methods used are fundamentally suitable for pressure measurement technologies. It should be emphasized that these results were achieved at moderate pressures of up to 5 bar and with diamond materials that are comparatively easy to produce.
The scientific results obtained will now be presented to the specialist audience. A poster (#5.29) will be presented at the renowned 28th International Hasselt Diamond Workshop, which will take place from 28th February to 1st March 2024, organized by the University of Hasselt (Belgium). In parallel, a scientific publication has been prepared and is currently in the review process.
