The research on perovskite radiation detectors at the University of Bologna is focused on thin film devices for the direct detection of radiation. We investigate the interaction between thin films and high energy photons and protons and we explore the best device geometries and fabrication process that allow scalability over large area and onto flexible substrates.
I will discuss the major...
Hybrid organic/inorganic lead halide perovskites represent a breakthrough in the direct detection of ionizing radiation thanks to their solution processability, and their scalability over large areas on flexible plastic substrates. Flexible perovskite X-ray detectors are lightweight devices that can be operated at low-voltages and strongly limit the use of toxic materials and precursors....
High sensitivity and efficient X-ray detectors are needed to promote and boost their application as tools in medical diagnostics and radiotherapy. Lead halide perovskites have emerged recently as a novel class of material for efficient X-ray detection. Although 3D perovskites possess very interesting optoelectronic properties they suffer from low environmental and operational stability. Here...
The urgency for affordable and reliable detectors for ionizing radiation in medical diagnostics, nuclear control and particle physics is generating growing demand for innovative scintillator devices combining efficient scintillation, fast emission lifetime, high interaction probability with ionizing radiation, as well as mitigated reabsorption to suppress losses in large volume/high-density...
Lead halide perovskites (LHP) are rapidly emerging as efficient, low-cost, solution-processable scintillators for radiation detection. Most importantly, LHP can be embedded in suitable polymeric hosts to create composite materials and produce fast, efficient, and more sensitive detectors in a cost-effective way, to meet the specific demands of all up-to-date technological and medical...
Lead halide perovskite (LHP) nanocrystals show promise as scintillators due to their high atomic number, bright luminescence and tunable emission wavelength. Here, we present nanocomposite scintillators which consist of formamidinium lead halide perovskite nanocrystals in a polymer matrix. Mixed-halide FAPbBr$_{3x}$Cl$_{3(1-x)}$ nanocrystals were synthesised by a room-temperature...
Metal halide perovskites with APbX3 crystal structure show rapidly increasing global interest as a new generation of radiation detection materials alternative to CdZnTe. In this work, we present our results of the multiple single crystals growth of all-inorganic perovskite CsPbBr3 using Bridgman method. Crystals were prepared directly from CsBr and PbBr2 starting materials mixed with a various...
Proton detectors play a crucial role in various fields, including radiation monitoring, medical imaging, and particle physics research. Recently, metal halide perovskites have emerged as a promising candidate for proton detection, offering high radiation tolerance alongside their demonstrated remarkable capabilities in detecting X-rays, gamma rays, alpha particles, electrons, and neutrons....
Here we have fabricated and characterised CsPbBr3 wafers for direct X-ray detection. Gram-scale CsPbBr3 powder was synthesized by milling of CsBr and PbBr2 precursors in a planetary ball mill. 0.4 g of CsPbBr3 power was pressed into a pellet of 10 mm diameter by a hot-pressing method at 70º C. We have characterized the morphology and structural properties of the polycrystalline CsPbBr3 wafer...
An open discussion about key results, challenges and future work around single crystal perovskite detectors
The fabrication of perovskite-polymer composites offers improved stability in perovskite radiation detectors alongside properties such as flexibility or improved strength. The facile production of all-inorganic perovskite nanocrystals is a convenient and cost-effective source of radiation detecting material. Incorporating these nanocrystals into the thermoplastic filaments used for fused...
Halide perovskites one of the most promising materials for next-generation, highly sensitive, low-noise, direct high energy X-ray detectors due to their excellent optoelectronic properties including bandgap tunability, high photoluminescence quantum yields (PLQY), defect tolerance and chemical versatility. However, challenges for the successful commercialization of halide perovskites X-ray...
In this study, we have investigated the impact of ligand-assisted Inverse Temperature Crystallisation (ITC) growth of FAPbBr3 perovskite single crystals on X-ray sensitivity and the charge transport properties. The ligand 3-(Declydimethylammonio)-propane-sulfonate inner salt (DPSI) was used to synthesise these perovskite single crystals from solution and the initial impact of the ligand on the...
During the measurement of the hole photocurrent relaxations (illuminated anode), we noticed an unusually high current after the bias polarity was switched. Our setup was designed to suppress the majority of effects tied to parasitic capacitances and is expected to have RC=100ns-1μs depending on the capacitance of the sample. The majority of the observed effects on a scale of 10s of μs,...
In this study, we analyse the performance of polycrystalline pellets of FAPbBr3 as a semiconductor-based radiation detector, and study the impact of lead acetate (LA) on the FAPbBr3 X-ray detector performance. Using a hot-pressing method various FAPbBr3 pellets were fabricated with different concentrations of lead acetate to investigate the improvement in the pellet microstructure and X-ray...
Metal halide perovskite is a new semiconductor family with great potential in various applications such as X/γ-ray detectors, solar cells, light emission diodes, and lasers. Especially inorganic metal halide perovskites, such as e.g. CsPbI3 or CsPbBr3 feature high atomic numbers (ZCs = 55, ZPb = 82, ZBr = 35, and ZI = 53), an...
Photoconductive gain is a physical phenomenon typical of photoconductors, where a highly defective semiconducting photoactive material is between two ohmic contacts. Such trappingactivated mechanism amplifies the high energy radiation-induced current by a factor G, leading to e quantum efficiency exceeding 100% and providing high sensitivity to the radiation. It occurs when...
The ability to detect ionising radiation is crucial to many areas of modern-day life spanning use in medical imaging, cancer therapies, security, and environmental monitoring as well as potential in military field applications. Indirect detectors, also known as scintillators, operate by absorbing high energy X-rays then converting into lower energy photons that emit in the UV/Visible region....
Halide perovskites are generating excitement for low-cost yet high-performance optoelectronic devices. Recently they have demonstrated enormous potential for radiation detection such as X-rays as scintillator or direct detector device platforms.
Here, I will give a summary of our group's efforts towards understanding and developing halide perovskites for X-ray detector applications. Topics...
A review of perovskite detector research as Freiburg.
Porous materials have started to gather attention as promising X-ray detectors due to their ease of processing and chemical versatility enabling the incorporation of high Z atoms and maximising attenuation efficiencies while keeping functional porosity. Here, I will present our team’s activities in functionalising porous structures with perovskites, including high throughput screening for...
An open discussion about key results, challenges and future work around thin film and polycrystalline perovskite detectors
