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[Lecture Notes in Electrical Engineering] Sensors Volume 539 (Proceedings of the Fourth National Conference on Sensors, February 21-23, 2018, Catania, Italy) || Portable Optoelectronic System for Monitoring Enzymatic Chemiluminescent Reaction
摘要： This work presents a portable lab-on-chip system, based on thin film electronic devices and an all-glass microfluidic network, for the real-time monitoring of enzymatic chemiluminescent reactions. The microfluidic network is patterned, through wet etching, in a 1.1 mm-thick glass substrate that is subsequently bonded to a 0.5 mm-thick glass substrate. The electronic devices are amorphous silicon p-i-n photosensors, deposited on the outer side of the thinner glass substrate. The photosensors, the microfluidic network and the electronic boards reading out the photodiodes' current are enclosed in a small metallic box (10 × 8 × 15 cm3) in order to ensure shielding from electromagnetic interferences. Preliminary tests have been performed immobilizing horseradish peroxidase on the inner wall of the microchannel as model enzyme for detecting hydrogen peroxide. Limits of detection and quantification equal to 18 and 60 μM, respectively, have been found. These values are comparable to the best performances reported in literature for chemiluminescent-based optofluidic sensors.
关键词： Amorphous silicon,Photosensors,Enzymatic reactions,Anodic bonding,Horseradish peroxidase,Microfluidics
更新于2025-09-19 17:15:36
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Hydrogen bonding promoted simple and clean photo-induced reduction of C–X bond with isopropanol
摘要： We herein report a simple and clean photo-induced metal-free reduction of C–X bond under an atmosphere of air at room temperature. Isopropanol is used as both the reducing reagent and solvent. Various functional groups (acids, esters, alcohols, anilines, phenols, indoles, pyridines, cyano and trifluoromethyl groups) and other heterocyclic compounds are tolerated. Different organic halides (including C–I, C–Br and C–Cl bonds) can be dehalogenated with moderate to excellent yields. Polyhalides are also reduced chemoselectively and efficiently. DFT calculation suggests a six-membered ring transition state via C–X···H–O hydrogen bonding to decrease the activation energy.
关键词： metal-free,isopropanol,DFT calculation,hydrogen bonding,photo-induced reduction,C–X bond
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE CPMT Symposium Japan (ICSJ) - Kyoto, Japan (2018.11.19-2018.11.21)] 2018 IEEE CPMT Symposium Japan (ICSJ) - A Study of Adhesion Interface about Die Bonding Structure with Conductive Silver Paste
摘要： In the electronic packages, gold surfaces are useful for stable connections. In this paper, adhesion interface for die bonding structure with conductive silver paste is investigated. The adhesive interface between gold surface and epoxy resin is investigated in two approaches. The first-principles calculations are employed to optimize the structure and calculate the theoretical bonding strength. The fragment model is constructed for bisphenol-A type epoxy resin and a curing agent which includes dicyandiamide. The results show that a cyano group included in the hardener greatly interacts with ideal gold surface, whereas a hydroxyl group seems not to interact with them regardless of high polarity. This interaction is likely to come from the π-back donation. The predicted bonding strength is as high as 1.15GPa. Next, the actual die pad surfaces prepared with plating gold are characterized to presume the substantial bonding structure by analytical method. Besides, measurements of adhesive strength have been performed by using small size lap shear tests under various temperatures. These results show that there are altered layers at the top of plating gold, which seems to affect the interaction mechanisms to hydrogen bond and make the adhesive strength lower.
关键词： conductive paste,die attach,bonding mechanism,density functional theory,adhesive,interface
更新于2025-09-19 17:15:36
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Different hydrogen bonding environments of the retinal protonated Schiff base control the photoisomerization in channelrhodopsin-2
摘要： The first event of the channelrhodopsin-2 (ChR2) photocycle, i.e. trans-to-cis photoisomerization, is studied by means of quantum mechanics/molecular mechanics, taking into account the flexible retinal environment in the ground state. By treating the chromophore at the ab initio multiconfigurational level of theory, we can rationalize the experimental findings based on pump–probe spectroscopy, explaining the different and more complex scenario found for ChR2 in comparison to other rhodopsins. In particular, we find that depending on the hydrogen bonding pattern, different excited states are involved, hence making it possible to suggest one pattern as the most productive. Moreover, after photoisomerization the structure of the first photocycle intermediate, P500, is characterized by simulating the infrared spectrum and compared to available experimental data. This was obtained by extensive molecular dynamics, where the chromophore is described by a semi-empirical method based on density functional theory. The results clearly identify which counterion is responsible for accepting the proton from the retinal Schiff base: the side chain of the glutamic acid E123.
关键词： FTIR spectroscopy,quantum mechanics/molecular mechanics,retinal Schiff base,photoisomerization,channelrhodopsin-2,hydrogen bonding,excited states,molecular dynamics
更新于2025-09-19 17:15:36
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Association of 1-hexanol in mixtures with n-hexane: Dielectric, near-infrared and DFT studies
摘要： Association of 1-hexanol in n-hexane has been studied by measurements of nonlinear dielectric effect (NDE) and near-infrared (NIR) spectroscopy. Besides, the dipole moments of selected open and cyclic associates were determined by DFT (density functional theory) calculations. All measurements were performed in the whole range of mole fractions with a step of 0.1. From numerical fitting of the dielectric data we obtained populations of all species present in the mixture. Our results do not support common opinion about the exceptional role of cyclic tetramers. The most abundant cyclic species are trimers and population of the cyclic associates rapidly decreases with increasing size of associates. The variations in population of open associates are more complex and for mole fractions of 1-hexanol greater than 0.1 the relationships have a maximum, which shifts towards higher associates. In pure 1-hexanol this maximum is close to seven. From analysis of the dielectric data it results that at lower alcohol content dominate the cyclic species. When the concentration of 1-hexanol increases the equilibrium shifts towards formation of the linear associates. From NIR spectra we determined the overall population of the free OH in monomers and open associates. Next, these values were used for estimation of an average length of the open associates. It appears that an averaged size of the open associates determined from NIR spectra is higher than that from the dielectric data and these differences are more pronounced when the concentration of 1-hexanol increases. We discuss possible explanations of this observation. Assuming that the actual size of the open associates is between those obtained from both methods, one can estimate that the size of open associates is ranging from 3 to 15 in pure 1-hexanol. It seems that the higher associates are stabilized by interaction of the aliphatic chains.
关键词： NIR spectroscopy,1-hexanol,DFT,hydrogen bonding,associations,non-linear dielectric effect
更新于2025-09-19 17:15:36
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New perspective on the fluorescence and sensing mechanism of TNP chemosensor 2-(4,5-bis(4-chlorophenyl)-1H-imidazol-2-yl)-4-chlorolphenol
摘要： For TNP chemosensor 2-(4,5-Bis(4-Chlorophenyl)-1H-Imidazol-2-yl)-4-Chlorolphenol (HPICI), previous thought with no theoretical basis was that excited-state intramolecular proton transfer (ESIPT) process and the ground-state HPICI-TNP complex are mainly responsible for its fluorescence emission and the detection of TNP. However, this interpretation has been proved to be wrong by the present theoretical DFT/TDDFT explorations. Actually, the strong fluorescence of HPICI is mainly induced by the local excitation of the enol form HPICI(E) without ESIPT, and the fluorescence quenching by TNP is due to the photo-induced electron transfer (PET) process together with the cooperative effect of hydrogen-bonding interaction and π-π stacking interaction coexisting in the HPICI-TNP complex. The strengthened excited-state hydrogen bond promotes the PET process, thus facilitates the fluorescence quenching. This mechanism is proposed on the basis of the theoretical analyses on molecule geometry, binding energy, Gibbs free energy, electronic transitions, and frontier molecular orbitals (FMOs).
关键词： Fluorescence emission,Fluorescence quenching,Photo-induced electron transfer,Hydrogen-bonding interaction,Dynamical sensing mechanism,π-π stacking interaction
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE 69th Electronic Components and Technology Conference (ECTC) - Las Vegas, NV, USA (2019.5.28-2019.5.31)] 2019 IEEE 69th Electronic Components and Technology Conference (ECTC) - Laser Releasable Temporary Bonding Film with High Thermal Stability
摘要： A temporary bonding film using a unique, laser releasable pressure sensitive adhesive construction has been formulated to advance wafer level fan-out process technology development. The film format and excellent thermal and dimensional stability of the temporary bonding film are particularly well suited to address the developing needs of panel level fan-out processes. The development of wafer level packaging process technology provides many benefits, including increased density and performance, greater design flexibility, simplification of the supply chain and process, and improved yield and overall cost of the semiconductor package. Specifically, in the case of fan-out, technology advances allowing wafer thinning to as little as 30 microns, backside patterning, and handling of the wafer or panel during copper RDL processing have become possible.
关键词： RDL-first,Fan-out WLP,RDL-last,Temporary bonding de-bonding film,Laser releasable film
更新于2025-09-19 17:13:59
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Selective fluorescence sensing of H <sub/>2</sub> PO <sub/>4</sub><sup>a??</sup> by the anion induced formation of self-assembled supramolecular polymers
摘要： The utilization of anions to induce the formation of self-assembled supramolecular polymers in solution is an undeveloped area of host–guest chemistry. We report in this manuscript a comparative study of two tripodal anion receptors by hydrogen or halogen bonding interactions to form self-assembled supramolecular structures induced by the presence of anions. DOSY NMR and DLS experiments provided evidence for the formation of supramolecular structures in solution in both halogen and hydrogen bond donors with H2PO4? anions. The nucleation and elongation constants obtained using the thermodynamic model indicate that the polymers grow following an isodesmic mechanism. Emission studies demonstrate that only the formation of the supramolecular polymer between the halogen bond donor receptor and H2PO4? anions results in the appearance of the excimer emission band.
关键词： halogen bonding,hydrogen bonding,DLS,anion receptors,DOSY NMR,excimer emission,supramolecular polymers
更新于2025-09-19 17:13:59
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Enhanced bonding strength of InP/Si chip-on-wafer by plasma-activated bonding using stress-controlled interlayer
摘要： This study demonstrates high-yield InP/Si CoW plasma-activated bonding using a chip holder with pockets, the depth of which is precisely controlled. Additionally, finite element simulations are used to determine that the stress-controlled interlayer consisting of InP-based epitaxial layers with tensile strain effectively suppresses stress at the InP/Si bonding interface, which affects the bonding strength. Thus, a high bonding strength of 20 MPa in 2 mm × 2 mm InP chips on the Si substrate was achieved by introducing a superlattice structure consisting of GaInAsP and InP (with tensile strain) as the stress-controlled interlayer.
关键词： chip-on-wafer,plasma-activated bonding,bonding strength,InP/Si,stress-controlled interlayer
更新于2025-09-19 17:13:59
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Acetamidinium substituted methylammonium lead iodide perovskite solar cells with higher open-circuit voltage and improved intrinsic stability
摘要： We report Acetamidinium (AA) substituted methylammonium lead iodide perovskite solar cells. AA has a restricted C-N bond rotation, due to delocalized 3+ electron cloud over C-N bond and presence of an additional N-H bond (4H-bond in AA as compared to 3H-bond in MA). These bonding structures strengthen the electrostatic interaction and stabilizes the acetamidinium cation inside the perovskite matrix. AA, a larger cation, is substitutional only up to 10%. Devices made with 10% AA-substituted films show average Voc of 1.12 V, higher than the average Voc of 1.04 V in case of MAPbI3. This increase in Voc can be attributed to increase in carrier lifetime from 20 μs in case of MAPbI3 to 32 μs for 10% AA substituted films respectively. Devices with 18.29% champion and 16.3% average efficiency were fabricated for films with 10% AA. Degradation experiments confirm that the material stability also makes devices more stable; under ambient exposure (72–3% RH) devices with 10% AA retain 70% of their initial power conversion efficiencies (PCE) upto 480 h. Under same conditions, the PCE’s of reference MAPbI3 devices reduced to 43% of their initial value in 480h.
关键词： cation substitution,acetamidinium,solar cells,Halide perovskite,open circuit voltage,H-bonding,stability
更新于2025-09-19 17:13:59