Photophysical properties of donor (D)-acceptor (A)-donor (D) diketopyrrolopyrrole (A) systems as donors for applications to organic electronic devices.

Fourteen substituted diketopyrrolopyrrole (DPP) molecules in a donor (D)-acceptor (DPP)-donor (D) arrangement were designed. We employed density functional theory, time-dependent DFT, DFT-MRCI and the ab initio wave function second-order algebraic diagrammatic construction (ADC(2)) methods to investigate theoretically these systems. The examined aromatic substituents have one, two, or three hetero- and non-hetero rings. We comprehensively investigated their optical, electronic, and charge transport properties to evaluate potential applications in organic electronic devices. We found that the donor substituents based on one, two, or three aromatic rings bonded to the DPP core can improve the efficiency of an organic solar cell by fine-tuning the highest occupied molecular orbital/lowest unoccupied molecular orbital levels to match acceptors in typical bulk heterojunctions acceptors. Several properties of interest for organic photovoltaic devices were computed. We show that the investigated molecules are promising for applications as donor materials when combined with typical acceptors in bulk heterojunctions because they have appreciable energy conversion efficiencies resulting from their low ionization potentials and high electron affinities. This scenario allows a more effective charge separation and reduces the recombination rates. A comprehensive charge transfer analysis shows that D-A (DDP)-D systems have significant intramolecular charge transfer, further confirming their promise as candidates for donor materials in solar cells. The significant photophysical properties of DPP derivatives, including the high fluorescence emission, also allow these materials to be used in organic light-emitting diodes.

Transparent, flexible, and eco-friendly starch-based films for reversible optoelectronic noses for food spoilage monitoring in smart packaging.

A reversible optoelectronic nose is presented consisting of ten acid-base indicators incorporated into a starch-based film, covering a wide pH range. The starch substrate is odorless, biocompatible, flexible, and exhibits high tensile resistance. This optical artificial olfaction system was used to detect the early stages of food decomposition by exposing it to the volatile compounds produced during the spoialge process of three food products (beef, chicken, and pork). A smartphone was used to capture the color changes caused by intermolecular interactions between each dye and the emitted volatiles over time. Digital images were processed to generate a differential color map, which uses the observed color shifts to create a unique signature for each food product. To effectively discriminate among different samples and exposure times, we employed chemometric tools, including hierarchical cluster analysis (HCA) and principal component analysis (PCA). This approach detects food deterioration in a practical, cost-effective, and user-friendly manner, making it suitable for smart packaging. Additionally, the use of starch-based films in the food industry is preferable due to their biocompatibility and biodegradability characteristics.

Structural determination, characterization and computational studies of doped semiconductors base silicon phthalocyanine dihydroxide and dienynoic acids.

The chemical doping of silicon phthalocyanine dihydroxide (SiPc(OH)2), with (2E, 4Z)-5, 7-diphenylhepta-2, 4-dien-6-ynoic acids (DAc) with electron-withdrawing (BrDAc) and electron-donating (MeODAc) substituents is the main purpose of this work. Theoretical calculations were carried out on Gaussian16 software, with geometrical optimization of all involved species, and obtention of the highest occupied molecule orbital (HOMO), lowest unoccupied molecular orbital (LUMO), and the respective energy gaps. The theoretical calculations show two hydrogen bridge formations: the first one as a peripheral interaction between the terminal oxygen atoms from the acid unit and hydrogen atoms from the phthalocyanine aromatic rings. The second one as the interaction at the nitrogen atoms of the phthalocyanine, which are compelled to form a new flat plane far from the original flat phthalocyanine deck. These organic semiconductors were deposited as thin films and characterized by IR spectroscopy, atomic force microscopy (AFM), and the optical parameters were gathered from UV-Vis studies. The indirect and direct optical band gap, the onset gap and the Urbach energy were obtained. In order to compare the effect of the acids as dopants of the silicon phthalocyanine, the SiPc(OH)2-DAc films were electrically characterized. The SiPc(OH)2-DAc films exhibit an ambipolar electrical behavior, which is influenced by the incidence of different lighting conditions at voltages above 0.3V. The glass/ITO/SiPc(OH)2-MeODAc/Ag reaches a maximum current of 5.68 × 10-5 A for natural light condition, while the glass/ITO/SiPc(OH)2-BrDAc/Ag, reaches a maximum current of 9.21 × 10-9 A for white illumination condition.

Enhancing c-Si Solar Cell Efficiency in the UV Region: Photophysical Insights into the Use of Eu3+ Complexes for Down-Shifting Layer Applications.

[Eu(3DPIQC)3] (where DPIQC = 3-(diphenyl phosphoryl)-1-isoquinolinecarboxylate), a luminescent europium complex with antenna ligands, has been carefully embedded within a polyvinyl butyral (PVB) matrix and the resulting material was used to prepare films used as luminescent down-shifting layers (LDSLs) for crystalline Si-based solar cells. The films were characterized using photoluminescence spectroscopy, atomic force spectroscopy (AFM), UV-Vis spectroscopy, and fluorescence microscopy. The AFM analysis shows films with low surface roughness, while fluorescence microscopy revealed that the Eu complex embedded in PVB assumed a spheroidal configuration, a morphology especially beneficial for optical applications. The so-obtained LDSLs were utilized as energy converters in c-Si solar cells to enhance the utilization of high-energy photons, thereby improving their overall efficiency. The determination of photovoltaic parameters carried out before and after the deposition of the LDSLs on the c-Si cells confirms a positive effect on the efficiency of the cell. The Jsc increases from 121.6 mA/cm2 to 124.9 mA/cm2, and the open circuit voltage (Voc) is found to be unrelated to the complex concentration in the films. The fill factor (FF) remains constant with the Eu concentration. The EQE curves indicate an enhancement in the performance of the photovoltaic cells within the UV region of the spectrum for all coated devices. Electrochemical impedance spectroscopy (EIS) was also carried out in order to analyze the effect of the Eu complex in the charge transfer process of the devices.

A Hammett's analysis of the substituent effect in functionalized diketopyrrolopyrrole (DPP) systems: Optoelectronic properties and intramolecular charge transfer effects.

Diketopyrrolopyrrole (DPP) systems have promising applications in different organic electronic devices. In this work, we investigated the effect of 20 different substituent groups on the optoelectronic properties of DPP-based derivatives as the donor ( D )-material in an organic photovoltaic (OPV) device. For this purpose, we employed Hammett's theory (HT), which quantifies the electron-donating or -withdrawing properties of a given substituent group. Machine learning (ML)-based σ m , σ p , σ m 0 , σ p 0 , σ p + , σ p - , σ I , and σ R Hammett's constants previously determined were used. Mono- (DPP-X1 ) and di-functionalized (DPP-X2 ) DPPs, where X is a substituent group, were investigated using density functional theory (DFT), time-dependent DFT (TDDFT), and ab initio methods. Several properties were computed using CAM-B3LYP and the second-order algebraic diagrammatic construction, ADC(2), an ab initio wave function method, including the adiabatic ionization potential ( I P A ), the electron affinity ( E A A ), the HOMO-LUMO gaps ( E g ), and the maximum absorption wavelengths ( λ max ), the first excited state transition 1 S0 → 1 S1 energies ( ∆ E ) (the optical gap), and exciton binding energies. From the optoelectronic properties and employing typical acceptor systems, the power conversion efficiency ( PCE ), open-circuit voltage ( V OC ), and fill factor ( FF ) were predicted for a DPP-based OPV device. These photovoltaic properties were also correlated with the machine learning (ML)-based Hammett's constants. Overall, good correlations between all properties and the different types of σ constants were obtained, except for the σ I constants, which are related to inductive effects. This scenario suggests that resonance is the main factor controlling electron donation and withdrawal effects. We found that substituent groups with large σ values can produce higher photovoltaic efficiencies. It was also found that electron-withdrawing groups (EWGs) reduced E g and ∆ E considerably compared to the unsubstituted DPP-H. Moreover, for every decrease (increase) in the values of a given optoelectronic property of DPP-X1 systems, a more significant decrease (increase) in the same values was observed for the DPP-X2 , thus showing that the addition of the second substituent results in a more extensive influence on all electronic properties. For the exciton binding energies, an unsupervised machine learning algorithm identified groups of substituents characterized by average values (centroids) of Hammett's constants that can drive the search for new DDP-derived materials. Our work presents a promising approach by applying HT on molecular engineering DPP-based molecules and other conjugated molecules for applications on organic optoelectronic devices.

On the mechanical, electronic, and optical properties of the boron nitride analog for the recently synthesized biphenylene network: a DFT study.

CONTEXT: Recently, a new 2D carbon allotrope named biphenylene network (BPN) was experimentally realized. Here, we use density functional theory (DFT) calculations to study its boron nitride analogue sheet's structural, electronic, and optical properties (BN-BPN). Results suggest that BN-BPN has good structural and dynamic stabilities. It also has a direct bandgap of 4.5 eV and significant optical activity in the ultraviolet range. BN-BPN Young's modulus varies between 234.4[Formula: see text]273.2 GPa depending on the strain direction. METHODS: Density functional theory (DFT) simulations for the electronic and optical properties of BN-BPN were performed using the CASTEP package within the Biovia Materials Studio software. The exchange and correlation functions are treated within the generalized gradient approximation (GGA) as parameterized by Perdew-Burke-Ernzerhof (PBE) and the hybrid functional Heyd-Scuseria-Ernzerhof (HSE06). For convenience, the mechanical properties were carried out using the DFT approach implemented in the SIESTA code, also within the scope of the GGA/PBE method. We used the double-zeta plus polarization (DZP) for the basis set in these cases. Moreover, the norm-conserving Troullier-Martins pseudopotential was employed to describe the core electrons.

Chest wall volumes, diaphragmatic mobility, and functional capacity in patients with mucopolysaccharidoses.

PURPOSE: We investigated respiratory muscle strength, diaphragm mobility, lung function, functional capacity, quality of life, body composition, breathing pattern, and chest wall (VT,CW) and compartmental volumes of Mucopolysaccharidosis (MPS) patients and compared these variables with matched healthy individuals. METHODS: A cross-sectional study with data analyzed separately according to age group. A total of 68 individuals (34 MPS and 34 matched-healthy subjects) were included. Six-minute walking test assessed functional capacity and ultrasound assessed diaphragm mobility during quiet spontaneous breathing (QB). Optoelectronic plethysmography assessed VT,CW and breathing pattern during QB in two different positions: seated and supine (45° trunk inclination). RESULTS: Body composition, lung function, respiratory muscle strength, and functional capacity were reduced in MPS (all p < 0.01). Diaphragm mobility was only reduced in adolescents (p = 0.01) and correlated with body composition and breathing pattern. Upper chest wall compartmental volumes were significantly lower in MPS, while abdominal volume only differed significantly in adolescents. Percentage contribution (%) of upper ribcage compartments to tidal volume was reduced in MPS children, whereas %AB was significantly increased compared with healthy subjects. CONCLUSION: Lung function, respiratory muscle strength, functional capacity, diaphragm mobility, and quality of life are reduced in MPS compared with matched healthy subjects. VT,CW was mainly reduced due to pulmonary and abdominal ribcage impairment. Implications for RehabilitationReduction in respiratory muscle strength, functional capacity, diaphragm excursion and low lung volumes were found in individuals with Mucopolysaccharidoses (MPS).Chest wall volumes and the upper chest wall compartmental volumes during quiet spontaneous breathing are reduced in MPS.Assessment and monitoring of the respiratory system for individuals with MPS should be performed periodically through standardized assessments to enable identification of changes and early intervention by rehabilitation protocols.This study may provide the necessary basis for carrying out respiratoty rehabilitation protocols that can improving chest wall mechanics with breathing exercise in this group.

Recent Progress in Amine Gas Sensors for Food Quality Monitoring: Novel Architectures for Sensing Materials and Systems.

The increasing demand for food production has necessitated the development of sensitive and reliable methods of analysis, which allow for the optimization of storage and distribution while ensuring food safety. Methods to quantify and monitor volatile and biogenic amines are key to minimizing the waste of high-protein foods and to enable the safe consumption of fresh products. Novel materials and device designs have allowed the development of portable and reliable sensors that make use of different transduction methods for amine detection and food quality monitoring. Herein, we review the past decade's advances in volatile amine sensors for food quality monitoring. First, the role of volatile and biogenic amines as a food-quality index is presented. Moreover, a comprehensive overview of the distinct amine gas sensors is provided according to the transduction method, operation strategies, and distinct materials (e.g., metal oxide semiconductors, conjugated polymers, carbon nanotubes, graphene and its derivatives, transition metal dichalcogenides, metal organic frameworks, MXenes, quantum dots, and dyes, among others) employed in each case. These include chemoresistive, fluorometric, colorimetric, and microgravimetric sensors. Emphasis is also given to sensor arrays that record the food quality fingerprints and wireless devices that operate as radiofrequency identification (RFID) tags. Finally, challenges and future opportunities on the development of new amine sensors are presented aiming to encourage further research and technological development of reliable, integrated, and remotely accessible devices for food-quality monitoring.

Perspectivas y aplicaciones reales del grafeno después de 16 años de su descubrimiento / Perspectives and real applications of graphene at 16 years after its breakthrough / Perspectivas e aplicações reais do grafeno após 16 anos de sua descoberta

Resumen A 16 años del gran descubrimiento del grafeno los focos de atención vuelven a estar en este material con el reporte de su comportamiento superconductor dependiendo del apilado de sus capas. Sin embargo, su nombre durante estos últimos años no solo se ha relacionado a la superconductividad, sino que ha sido relacionado con una diversidad muy amplia de aplicaciones, en disciplinas muy diversas, entre las que cabe mencionar: materiales opto-electrónicos, electrodos para catálisis, dispositivos para tratamiento de desechos, biosensores, entre otros. Esto ha hecho que un gran número de grupos de investigación se hayan interesado no solo en estudiar sus propiedades, sino también en investigar nuevos métodos sintéticos que puedan ser escalables a niveles industriales, sin perder sus propiedades electrónicas y mecánicas. A pesar de los numerosos estudios y los recursos invertidos en grafeno no todas las aplicaciones han llegado a ser una realidad, en esta revisión se muestran algunas de las más exitosas.

Abstract 16 years after the great discovery of graphene, the focus and attention are again on this material after the report of its superconducting behavior depending on the stacking of its layers. The graphene has not only been related to superconductivity but has also been related to a wide diversity of applications, in very diverse disciplines. Among them, we can mention: Opto-electronic materials, electrodes for catalysis, devices for waste-water treatment, biosensors, batteries, and solar cells. This has caused a large number of research groups to be interested not only in the study of its properties, but also in the research of new synthetic methods that can be scaled to industrial levels, without losing its electronic and mechanical properties. Despite numerous studies and resources invested in graphene, not all applications have become a reality, some of the most successful are shown in this review.

Resumo 16 anos após a grande descoberta do grafeno, o foco e as atenções voltam a ser neste material com o relato de seu comportamento supercondutor em função do empilhamento de suas camadas. No entanto, seu nome nos últimos anos não tem sido apenas relacionado à supercondutividade, mas tem sido relacionado a uma diversidade muito ampla de aplicações, em disciplinas muito diversas. Entre eles podemos citar: materiais optoeletrônicos, eletrodos para catálise, dispositivos para tratamento de águas residuais, biossensores, baterias e células solares. Isso fez com que um grande número de grupos de pesquisa se interessassem não apenas em estudar suas propriedades, mas muitas pesquisas também foram feitas na geração de métodos sintéticos que pudessem ser dimensionados para níveis industriais, sem perder suas propriedades eletrônicas e mecânicas. Apesar dos inúmeros estudos e recursos investidos em grafeno, nem todas as aplicações se tornaram realidade, algumas das mais bem-sucedidas são apresentadas nesta revisão.

Bond order effects on the optoelectronic properties of oxygen/sulfur functionalized adamantanes.

The objective of this work, is to study adamantanes and to tune their bandgap, since pure adamantane is considered as an insulator due to its high bandgap energy. For this, we doped adamantane with oxygen and sulfur atoms, thus obtaining 730 different structures with double bonds and 730 different structures with single bonds, for a total of 1460 structures, and compared their properties. Among all, 31 molecules were selected that best represented the reduced bandgap behavior. The calculations with greater precision in its results were made using the Local Density Approximation (LDA), in the Density-Functional Theory (DFT) formalism, with PWC functional and TNP basis set. The electronic and optical properties were analyzed, by calculating the energy gap and absorption spectrum. Importantly, we observed that molecules doped with sulfur atoms (double bonds) had their energy gap reduced significantly compared to molecules doped with sulfur and/or oxygen atom with single bonds and pristine adamantane. It was found that in the absorption spectrum, the sulfur-doped structures had their spectrum shifted to the visible region, a fact that becomes relevant for potential dyes and optoelectronic applications. From the seven selected functionalized adamantanes (ADD-04, ADD-05, ADD-07, ADD-19, ADD-20, ADD-41, and ADD-48), any of these could be used as a dye. However, the ADD-20 molecule in particular, which presented optical absorption near (RGB) primary colors, could indicate a potential quantum dot material for application in developing screens of various electronic devices.

Chemical QR Code: A simple and disposable paper-based optoelectronic nose for the identification of olive oil odor.

Olive oil is an appreciated food product with high nutritional value, besides being an essential component in many culture diets. In this study, we present for the first time the application of a simple and non-invasive paper-based optoelectronic nose designed in a QR code configuration to evaluate the odor of olive oils. The chemical QR code was fabricated by the addition of 12 dyes, which provided high dimensional data resulting from the interaction between the volatile compounds and the colorimetric array. The color changes were employed to build differential maps with a unique fingerprint (i) to discriminate between olive oil and other edible oil samples; (ii) to quantify nonanaldehyde as an oxidation marker; and (iii) to identify oxidized oils through principal component analysis (PCA) and hierarchical component analysis (HCA). By developing suitable mobile apps, we anticipate the employment of the chemical QR code for portable, low-cost, and in-situ evaluation of food product quality.

Cubane and cubanoid: Structural, optoelectronic and thermodynamic properties from DFT and TD-DFT method.

In this paper, we report structural, electronic and optical properties of cubane (C8H8) and cubanoids (cubane-like molecules) using Density Functional Theory (DFT). The cubanoids are cubanes for which Carbon atoms have been substituted by Nitrogen (N), Phosphorus (P), Boron (B), Silicon (Si), Arsenic (As), Antimony (Sb) or Bismuth (Bi) atoms. These molecules presented exceptional stability with several different symmetry point groups, being the majority Td. All calculated vibrational frequencies are positive for any studied molecules indicating that all these structures are in a stable state. The HOMO-LUMO gaps and DOS were calculated converged towards to values between 1.87 eV and 5.61 eV, actually showing promising electronic properties (Just for comparison, the cubane energy gap is 7.50 eV). The optical absorptions were also calculated for the cubanoid structure using the Time-Dependent Density Functional Theory (TD-DFT). Their dependence on the wavelength is analyzed, where five of theses structures absorb on the visible region. Finally, the extrapolation of thermodynamic properties indicates that these cubanoid could be potentially synthesized spontaneously, where four structures, the synthesis would occur for temperatures below 400 K, while for Si4Bi4H4 structure, the synthesis would occur at room temperature.

Paper-based optoelectronic nose for identification of indoor air pollution caused by 3D printing thermoplastic filaments.

Commercial printers based on fused deposition modeling (FDM) are widely adopted for 3D printing applications. This method consists of the heating of polymeric filaments over the melting point followed by their deposition onto a solid base to create the desirable 3D structure. Prior investigation using chromatographic techniques has shown that chemical compounds (e.g. VOCs), which can be harmful to users, are emitted during the printing process, producing adverse effects to human health and contributing to indoor air pollution. In this study, we present a simple, inexpensive and disposable paper-based optoelectronic nose (i.e. colorimetric sensor array) to identify the gaseous emission fingerprint of five different types of thermoplastic filaments (ABS, TPU, PETG, TRITAN and PLA) in the indoor environment. The optoelectronic nose is comprised of selected 15 dyes with different chemical properties deposited onto a microfluidic paper-based device with spots of 5 mm in diameter each. Digital images were obtained from an ordinary flatbed scanner, and the RGB information collected before and after air exposure was extracted by using an automated routine designed in MATLAB, in which the color changes provide a unique fingerprint for each filament in 5 min of printing. Reproducibility was obtained in the range of 2.5-10% (RSD). Hierarchical clustering analysis (HCA) and principal component analysis (PCA) were successfully employed, showing suitable discrimination of all studied filaments and the non-polluted air. Besides, air spiked with vapors of the most representative VOCs were analyzed by the optoelectronic nose and visually compared to each filament. The described study shows the potential of the paper-based optoelectronic nose to monitor possible hazard emissions from 3D printers.

Influence of posture, sex, and age on breathing pattern and chest wall motion in healthy subjects.

OBJECTIVE: We evaluated the effects of posture, sex, and age on breathing pattern and chest wall motion during quiet breathing in healthy participants. METHODS: Eighty-three participants aged 42.72 (SD=21.74) years presenting normal pulmonary function were evaluated by optoelectronic plethysmography in the seated, inclined (with 45° of trunk inclination), and supine positions. This method allowed to assess the chest wall in a three dimensional way considering the chest wall as three compartments: pulmonary rib cage, abdominal rib cage and abdomen. RESULTS: Posture influenced all variables of breathing pattern and chest wall motion, except respiratory rate and duty cycle. Chest wall tidal volume and minute ventilation were reduced (p<0.05) in both sexes from seated to inclined and from seated to supine positions, mainly in males. Moreover, moving from seated to supine position significantly increased the percentage contribution of the abdomen to the tidal volume in both sexes (p<0.0001). Regarding sex, women showed higher contribution of thoracic compartment compared to men (p=0.008). Aging provided reductions on rib cage contributions to tidal volume that were compensated by increases of abdomen contributions (p<0.0001). In addition, increases in end-inspiratory and end-expiratory volumes over the years were observed. CONCLUSION: The degree of contribution of chest wall compartments is dependent on posture, sex, and age. Therefore, verticalization increases expansion of pulmonary rib cage as well as horizontalization increases abdominal displacement. Women presented higher thoracic contribution to tidal volume than men. Aging reduces rib cage contributions to tidal volume that were compensated by increases of abdomen contributions.

Fabrication of Hybrid Membranes Containing Nylon-11 and Organic Semiconductor Particles with Potential Applications in Molecular Electronics.

Chemical degradation is a major disadvantage in the development of organic semiconductors. This work proposes the manufacture and characterization of organic semiconductor membranes in order to prevent semiconductor properties decreasing. Semiconductor membranes consisting of Nylon-11 and particles of π-conjugated molecular semiconductors were manufactured by high-vacuum evaporation followed by thermal relaxation. Initially, and with the aim of obtaining semiconductor particles, bulk heterojunction (BHJ) was carried out using green chemistry techniques between the zinc phthalocyanine (ZnPc) and the zinc hexadecafluoro-phthalocyanine (F16ZnPc) as n-type molecular semiconductors with the p-type molecular semiconductor dibenzotetrathiafulvalene (DBTTF). Consequently, the π-conjugated semiconductors particles were embedded in a Nylon-11 matrix and characterized, both structurally and considering their optical and electrical properties. Thin films of these materials were manufactured in order to comparatively study the membranes and precursor semiconductor particles. The membranes presented bandgap (Eg) values that were lower than those obtained in the films, which is an indicator of an improvement in their semiconductor capacity. Finally, the membranes were subjected to accelerated lighting conditions, to determine the stability of the polymer and the operating capacity of the membrane. After fatigue conditions, the electrical behavior of the proposed semiconductor membranes remained practically unaltered; therefore, they could have potential applications in molecular electronics. The chemical stability of membranes, which did not degrade in their polymer compound, nor in the semiconductor, was monitored by IR spectroscopy.

After-Effects of Thixotropic Maneuvers on Chest Wall and Compartmental Operational Volumes of Healthy Subjects Using Optoelectronic Plethysmography.

The volumes assessed by optoelectronic plethysmography (OEP) and based on a three-compartmental model provide an accurate breath-by-breath index of expiratory and inspiratory (ribcage muscles and diaphragm) muscle length. Thus, after performing thixotropic maneuvers, OEP may also provide evidence regarding the history-dependent properties of these muscles. We studied the after-effects of different thixotropic conditionings on chest wall (CW) and compartmental operational volumes of 28 healthy subjects (25.5 ± 2.2 years, FVC%pred 94.8 ± 5.5, and FEV1 %pred 95.5 ± 8.9) using OEP. Conditionings were composed of inspiratory or expiratory contractions performed from total lung capacity (TLC) or residual volume (RV). The study protocol was composed of three consecutive contractions of the same maneuver, with 60 s of spontaneous breathing in between, and after-effects were studied in the first seven respiratory cycles of each contraction. Cumulative effects were also assessed by comparing the after-effects of each thixotropic maneuver. Inspiratory contractions performed from both TLC and RV acutely increased end-inspiratory (EIV) CW volumes (all p < 0.0001), mainly on both upper and lower ribcage compartments (i.e., non-diaphragmatic inspiratory muscles and diaphragm, respectively); while, expiratory contractions from RV decreased CW volumes (p < 0.0001) by reducing the upper ribcage and abdominal volumes (all p < 0.0001). The response of the thixotropic maneuvers did not present a cumulative effect. In healthy, the use of the three-compartmental model through OEP allows a detailed assessment of the diaphragm, inspiratory and expiratory muscle thixotropy. Furthermore, specific conditioning maneuvers led to thixotropy of the inspiratory ribcage, diaphragm, and expiratory muscles.

New Triphenylamine-Based Oligomeric Schiff Bases Containing Tetraphenylsilane Moieties in the Backbone.

Three new triphenylamine-based oligomeric Schiff bases (polySB1, polySB2 and polySB3) containing tetraphenylsilane core (TPS-core) in the main chain were obtained from TPS-core-based diamines and bis(4-formylphenyl)phenylamine by a high-temperature polycondensation reaction. These new oligomers were structurally characterized by FT-IR, NMR and elemental analysis. All polySBs were highly soluble in common organic solvents, such as chloroform, tetrahydrofuran and chlorobenzene. Samples showed moderate molecular average molecular weight (Mw) and a high thermal stability above 410 °C. Likewise, polySBs showed absorption near 400 nm in the UV-vis range and photoluminescence. The HOMO levels and band-gap values were found in the ranges of -6.06 to -6.18 eV and 2.65⁻2.72 eV, respectively. The lowest band-gap value was observed for polySB2, which could be attributed to a more effective π-conjugation across the main chain. The results suggest that silicon-containing polySBs are promising wide-band-gap semiconductors materials for optoelectronic applications.

Development of an Optoelectronic Sensor for Detecting and Classifying Fruit Fly (Diptera: Tephritidae) for Use in Real-Time Intelligent Traps.

Fruit flies (Diptera: Tephritidae) cause losses to world fruit growing. For a fast and effective control of the pest, it is necessary to identify the species and their populations. Thus, we developed an infrared optoelectronic sensor using phototransistors to capture the signal of the partial occlusion of the infrared light caused by the beating of the fly wings. Laboratory experiments were conducted using the sensor to capture the wing beat signal of A. fraterculus and C. capitata. The captured signals were used to obtain the characteristics of the flies' wing beats frequency and for a production of a dataset made available as one of the results of this work. For the passage detection, we developed the algorithm of detection of events of passage (PEDA) that uses the root mean square (RMS) value of a sliding window applied to the signal compared to a threshold value. We developed the algorithm of detection of events of passage (CAEC) that uses the techniques of autocorrelation and Fourier transform for the extraction of the characteristics of the wings' beat signal. The results demonstrate that it is possible to use the sensor for the development of an intelligent trap with detection and classification in real time for A. fraterculus and C. capitata using the wing beat frequency obtained by the developed sensor.

Upconversion Nanocomposite Materials With Designed Thermal Response for Optoelectronic Devices.

Upconversion is a non-linear optical phenomenon by which low energy photons stimulate the emission of higher energy ones. Applications of upconversion materials are wide and cover diverse areas such as bio-imaging, solar cells, optical thermometry, displays, and anti-counterfeiting technologies, among others. When these materials are synthesized in the form of nanoparticles, the effect of temperature on the optical emissions depends critically on their size, creating new opportunities for innovation. However, it remains a challenge to achieve upconversion materials that can be easily processed for their direct application or for the manufacture of optoelectronic devices. In this work, we developed nanocomposite materials based on upconversion nanoparticles (UCNPs) dispersed in a polymer matrix of either polylactic acid or poly(methyl methacrylate). These materials can be processed from solution to form thin film multilayers, which can be patterned by applying soft-lithography techniques to produce the desired features in the micro-scale, and luminescent tracks when used as nanocomposite inks. The high homogeneity of the films, the uniform distribution of the UCNPs and the easygoing deposition process are the distinctive features of such an approach. Furthermore, the size-dependent thermal properties of UCNPs can be exploited by a proper formulation of the nanocomposites in order to develop materials with high thermal sensitivity and a thermochromic response. Here, we thus present different strategies for designing optical devices through patterning techniques, ink dispensing and multilayer stacking. By applying upconverting nanocomposites with unique thermal responses, local heating effects in designed nanostructures were observed.

CuPc: Effects of its Doping and a Study of Its Organic-Semiconducting Properties for Application in Flexible Devices.

This study refers to the doping of organic semiconductors by a simple reaction between copper phthalocyanine and tetrathiafulvalene or tetracyanoquinodimethane. The semiconductor films of copper phthalocyanine, doped with tetrathiafulvalene donor (CuPc-TTF) and tetracyanoquinodimethane acceptor (CuPc-TCNQ) on different substrates, were prepared by vacuum evaporation. The structure and morphology of the semiconductor films were studied with infrared (IR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The absorption spectra for CuPc-TTF, recorded in the 200⁻900 nm UV⁻vis region for the deposited films, showed two peaks: a high energy peak, around 613 nm, and a second one, around 695 nm, with both peaks corresponding to the Q-band transition of the CuPcs. From the spectra, it can also be seen that CuPc-TTF has a B-band at around 330 nm and has a bandgap of approximately 1.4 eV. The B-band in the CuPc-TCNQ spectrum is quite similar to that of CuPc-TTF; on the other hand, CuPc-TCNQ does not include a Q-band in its spectrum and its bandgap value is of approximately 1.6 eV. The experimental optical bandgaps were compared to the ones calculated through density functional theory (DFT). In order to prove the effect of dopants in the phthalocyanine semiconductor, simple devices were manufactured and their electric behaviors were evaluated. Devices constituted by the donor-acceptor active layer and by the hollow, electronic-transport selective layers, were deposited on rigid and flexible indium tin oxide (ITO) substrates by the vacuum sublimation method. The current⁻voltage characteristics of the investigated structures, measured in darkness and under illumination, show current density values of around 10 A/cm² for the structure based on a mixed-PET layer and values of 3 A/cm² for the stacked-glass layered structure. The electrical properties of the devices, such as carrier mobility (µ) were obtained from the J⁻V characteristics. The mobility values of the devices on glass were between 1.59 × 108 and 3.94 × 1010 cm²/(V·s), whereas the values of the devices on PET were between 1.84 × 108 and 4.51 × 108 cm²/(V·s). The different behaviors of the rigid and flexible devices is mainly due to the effect of the substrate.