SBIR/STTR Award attributes
In this SBIR project, we will develop an efficient, low-cost, rad-hard imager of ionizing radiation (focusing primarily on gamma-rays during Phase I but also expanding to fast neutrons during Phase II) that has high angular (< 2°) and energy resolution (< 2% at 662 keV) that can be handheld (< 4 kg system mass) and has a low operating bias (< 200 V) for its sensing pixel elements. Current radiation imagers are limited by their poor energy resolution and / or high system costs, especially for dual-mode (photon and fast neutron) imaging. Perovskite materials can solve these problems due to its low-cost material growth (using solution-based techniques) and its superior cross-section and semiconductor properties, enabling high-performance radiation detection (including of fast neutrons) at 1 – 2 orders of magnitude lower material costs than existing semiconductor or scintillator materials. While perovskite detectors have been demonstrated, the scalable growth techniques and device engineering of perovskite sensors necessary to realize commercial detection and imaging systems needs further development. In particular, the material yield, consistency, and device fabrication strategies need significant improvement. To demonstrate the feasibility of transitioning perovskite materials into commercializable imaging systems, we have developed several strategies that will be optimized during this Phase I work. The first step of our efforts will be to optimize the perovskite material chemistry to enable the high-resolution detection of gamma-rays (< 2% at 662 keV and 5 cm3) perovskite solids. Note that we have previously developed two such scalable growth methods: Field-Assisted Sintering Technology (FAST) and Axially-Forced Convection (AFC) growth techniques to grow large perovskite solids. During this project, these two methods will be optimized and compared for their ability to grow high-quality perovskites. While optimizing the growth techniques, we will also evaluate the sensors’ radiation survivability and develop the device architecture and deposition strategies needed to form stable, rectifying p-i-n contacts to perovskites, building on our previous work on low-temperature cast rectifying contacts. The problems caused by high detector capacitance (up to 100 nF cm-2 for perovskite detectors) on commercial readout circuitry will be addressed by designing a customized capacitance-insensitive preamplifier by optimizing a previous design we developed. When combined, the successful demonstration of our Phase I work will prove the feasibility of low-cost, high-energy, high-performance perovskite imagers.
