Tarik Dickens

Space travel is hazardous because its environment contains higher amounts of radiation compared to the Earth. For this reason, materials must be optimized for radiation shielding to protect organic life forms and electrical equipment. This project focuses on creating effective shielding for protection against space radiation. The Stopping Range of Ions in Matter (SRIM) is a software used to simulate the electronic stopping power of protons in materials and can assist in optimizing them for shielding. SRIM was used to simulate diamond (D), graphite (G), carbon nanotubes (CNT) and combinations of material layer ordering consisting of the three allotropes with 145 MeV Protons. Results showed that diamond, graphite and carbon nanotube (D_G_CNT) were the optimal order of layering for minimum penetration depth amongst these multi-layered materials. The multi-layered material CNT_G_D having the least effective stopping power reordered to D_G_CNT, the travel depth reduces by 28.14%, showing how layer ordering effects the stopping power of a material.

A 3D-printed Cd-doped Cs ₄ MnBi ₂ Cl ₁₂ /PLA composite achieves a water-stable X-ray scintillator with a 47% PLQY, 605 nm bright orange emission, and 5 LP mm ⁻¹ spatial resolution under high-flux X-ray, supporting sustainable industrial imaging.

Halide perovskites have exhibited great research impact for developing innovative materials with novel properties. Here, we report the synthesis of different caesium lead bromide perovskites using different (Cs/Pb) molar ratios and fabrication of their corresponding perovskite/polyvinylidene fluoride (PVDF) composites, as well as study of their structural and UV-photodetection properties. Spin-coated perovskite/PVDF composite thin films revealed strong oriented XRD diffraction peaks along the c-axis direction (00l) with homogeneously distributed perovskite microcrystals in the polymer matrix. The high-Cs containing perovskite/PVDF composite, with Cs/Pb (3/1) molar ratio, demonstrated the highest green emission under UV light and its corresponding UV-photodetector exhibited the highest UV photo-responsivity. These results highlight the importance of structural modulation and additive manufacturing for tailoring the optoelectronic properties of halide perovskites.

Structural modulation of (Cs/MA) mixed-cation copper perovskite via (Cl/Br) mixed-halide engineering led to enhancement of the piezoelectric response.

Four different primary, secondary, and tertiary amine-based bismuth perovskites have shown good potential towards photodetection application with the highest photo-detectivity of branched primary amine-based devices compared to other devices.

Direct ink write deposition facilitates line‐by‐line extrusion of inks spanning wide viscoelastic ranges. Following deposition, post processing technologies permit tuning of the extrudate's material property characteristics—ultraviolet (UV) irradiation, facilitating the photopolymerization of UV‐reactive catalyst solutions, permits targeted modification of the extrudate's microstructure and in situ tuning of extrudate macrostructure. This report analyzes the morphological, rheological, and microstructural property relationships governing the printability, and processivity, of extruded UV‐curable resin inks for delineation of sufficiency and optimization of ink printability utilizing direct ink write technologies. A design‐of‐experiments approach is implemented to quantify significance regarding an extrudate's dimensional response to extrusion parameter variation and in situ processing parameters, identifying proportionally of nozzle velocity, nozzle height, and UV irradiation exposure with extrudate aspect ratio, reflected by respective maximum extrudate aspect ratio increases of 158% and 109%, regarding 121 and 123K resin inks. Finally, the relationship between extrudate morphology and microstructure variation was assessed via dielectric cure monitoring, whereby an extrudate's ion viscosity was calculated in relation to its rheological modulus, reflecting the relationship between an extrudate's morphology, rheological response, and printability, regarding its microstructural variation.

This research introduces a readily available and non-chemical combinatorial production approach, known as the laser-induced writing process, to achieve laser-processed conductive graphene traces. The laser-induced graphene (LIG) structure and properties can be improved by adjusting the laser conditions and printing parameters. This method demonstrates the ability of laser-induced graphene (LIG) to overcome the electrothermal issues encountered in electronic devices. To additively process the PEI structures and the laser-induced surface, a high-precision laser nScrypt printer with different power, speed, and printing parameters was used. Raman spectroscopy and scanning electron microscopy analysis revealed similar results for laser-induced graphene morphology and structural chemistry. Significantly, the 3.2 W laser-induced graphene crystalline size (La; 159 nm) is higher than the higher power (4 W; 29 nm) formation due to the surface temperature and oxidation. Under four-point probe electrical property measurements, at a laser power of 3.8 W, the resistivity of the co-processed structure was three orders of magnitude larger. The LIG structure and property improvement are possible by varying the laser conditions and the printing parameters. The lowest gauge factor (GF) found was 17 at 0.5% strain, and the highest GF found was 141.36 at 5%.

A semiconductor-polymer composite was developed in this work consisting of inorganic halide perovskite (CsPbBr3) crystals embedded in polylactic acid (PLA) matrix. The composite exhibits the essential semiconductor properties of CsPbBr3 and the easy processability of PLA, enabling 3D printed tandem X-ray detectors. The tandem detectors demonstrated a sensitivity of 383 μC Gyair-1 cm-2 when four layers and total 600 µm thick CsPbBr3-PLA were printed. This sensitivity is 23X of single-layer detectors with same absorber thickness. The result indicates that 3D printed tandem detectors can overcome the X-ray absorption vs. charge carrier collection tradeoff in conventional single-layer detectors towards high performance radiation detection.

Dynamic bond exchanging vitrimers have emerged recently due to their malleability, self‐heal ability, recyclability, and mechanical stability. Likewise, 3D printing is consciously introduced at different platforms for ease of fabrication, high throughput, cost‐effectiveness, and waste reduction. These two distinctive techniques have recently made their consensus performance, resulting from a phenomenal change in the printing field. Conventionally, thermoplastic inks have been primarily used in 3D printing, owing to their effortless processability. At the same time, thermosets were utilized for their superior mechanical strength. However, these two essential properties have been required to be presented in the printed material. In that scenario, thermoset vitrimer materials have been introduced in 3D printing, where malleability and mechanical stability have been observed in the same material. Thus, this article details the recent vitrimer material included with the different 3D printing system systems with their reported results to understand and make them widespread. Eventually, the outlook and perspectives could be helpful to understand and enhance this specific field.