The commercialization of next-generation technologies, including optical interconnects, quantum computing, AR/VR, and medical diagnostics, requires a low-loss photonic platform offering compact, multifunctional systems in the visible and near-infrared range. Although silicon nitride (SiN) is an excellent material due to its ultra-low loss and broad transparency window, integrating active components such as light sources, modulators and photodetectors from diverse material platforms in a scalable, reliable way remains challenging. Micro-transfer printing is an emerging wafer-scale heterogeneous integration technology that can be implemented as a back-end post-processing step without disrupting the primary in-line fabrication process. In this work, we present a dual LPCVD SiN layer platform fabricated in a 200 mm CMOS pilot line, that incorporates micro-transfer printing modules, allowing the integration of active components on well defined recesses. A hydrogenated amorphous silicon layer is also available to increase the versatility of the platform allowing for evanescently-coupled III-V lasers as well as other passive functionality in the near-infrared region. We report full wafer-scale measurements showing low optical SiN losses of 4 dB/cm and 0.23 dB/cm at a wavelength of 488 nm and 940 nm respectively. In addition, a transition loss of only 0.35 dB is obtained from the SiN to the a-Si:H layer, in good agreement with simulated values. Finally, to showcase more advanced functionality, GaAs-based gain sections are micro-transfer printed on several dies, achieving consistent die-to-die lasing at 970 nm with on-chip optical powers of approximately 1 mW. These results showcase the potential of the integrated photonics platform towards unlocking a wide range of new applications in the sub-1-μm spectral region.
Proteins are promising raw materials that can be combined with polyacrylates to produce sustainable latexes for film-forming applications. However, they have low resistance to water and organic solvents, which could be improved by cross-linking the film during the drying process. In this work, self-cross-linking hybrid protein-acrylic latexes were produced through semicontinuous copolymerization of an acrylic formulation containing different amounts of diacetone acrylamide (DAAM) using zein-casein bioparticles as seed. The film cross-linking occurred through the reaction between the ketone groups of DAAM and the hydrazide group of adipic acid dihydrazide during film drying. The cross-linked films exhibited superior resistance to water and organic solvents, as well as better mechanical properties compared to the un-cross-linked one. Finally, desirable properties, such as excellent film-forming ability, high blocking resistance, and low opacity, highlight the suitability of these latexes as candidates for the development of a next-generation of eco-friendly coatings.
This work explores the facet-dependent mechanisms governing ethanol dehydrogenation and dehydration on cerium oxide (CeO2) nanocrystals. Shape-controlled CeO2 nanocubes ({1 0 0} facets) and nanosheets ({1 1 1} facets) were synthesized and evaluated under steady-state conditions. Catalytic performance was significantly influenced by surface structure: nanosheets exhibited markedly higher ethanol conversion (90 % at 400 degrees C) compared to nanocubes (18 %), with selectivity transitioning from acetaldehyde to ethylene as temperature increased. Operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), combined with modulation excitation spectroscopy and phase-sensitive detection (MES-PSD), enabled the identification of key surface intermediates. Bidentate ethoxy species predominated on {1 0 0} facets, while monodentate ethoxy species were favored on {1 1 1} facets. Phase-resolved spectra revealed that acetaldehyde forms rapidly via alpha C-H bond cleavage, whereas ethylene formation proceeds through slower beta C-H activation involving enolatetype intermediates. The enhanced reactivity of {1 1 1} facets was attributed to their ability to orient ethoxy species favorably for C-O and C-H bond activation, while the accumulation of thermally stable acetates limited reactivity on {1 0 0} surfaces. These findings establish a direct correlation between CeO2 morphology, surface chemistry, and product distribution, providing mechanistic insight relevant to the rational design of selective oxidation catalysts.
Introduction: Heavy metal contamination in aquatic environments represents a major environmental and public health concern due to the toxicity and bioaccumulation of ions such as Hg[II], Pb[II], and Zn[II]. Laboratorybased techniques such as AAS and ICP-MS provide high sensitivity but often require specialized instrumentation and off-site analysis. Surface Plasmon Resonance (SPR) sensors offer a complementary label-free route for real-time optical monitoring due to their rapid response and sensitivity to refractive-index changes. Methodology: The optical response of the proposed multilayer structure was numerically investigated using the Transfer Matrix Method (TMM) and Fresnel equations under TM-polarized light at 633 nm. Key performance parameters, including sensitivity, Full Width at Half Maximum (FWHM), Figure of Merit (FoM), Detection Accuracy (DA), Quality Factor (QF), and Limit of Detection (LoD), were systematically analyzed for Hg[II], Pb[II], Zn[II], and binary ion mixtures. Results and discussion: A 60 nm Al layer combined with a 23 nm TiO2 coating provided a favorable balance between attenuation depth and resonance sharpness. Among the evaluated 2D materials, BP showed the most suitable response because of its low optical loss and narrow FWHM. The optimized B-sil/Al/TiO2/BP configuration achieved a maximum sensitivity of 512.47 degrees/RIU for Hg[II], while maintaining high sensitivity for Pb[II], Zn[II], and binary mixtures, confirming its capability for trace-level detection. Electric field analysis revealed strong field localization at the TiO2/BP/analyte interface, enhancing light-matter interaction and sensing resolution. Conclusion: The proposed B-sil/Al/TiO2/BP SPR sensor demonstrated excellent optical performance, high sensitivity, and strong potential for real-time monitoring of heavy metal ions in aqueous environments.
