Cluster Formation of Self-Assembled Triarylbismuthanes and Charge Transport Characterizations of Gold-Triarylbismuthane-Gold Junctions.

Organometallic molecules are promising for molecular electronic devices due to their potential to improve electrical conductance through access to complex orbital covalency that is not available to light-element organic molecules. However, studies of the formation of organometallic monolayers and their charge transport properties are scarce. Here, we report the cluster formation and charge transport properties of gold-triarylbismuthane-gold molecular junctions. We found that triarylbismuthane molecules with -CN anchoring groups form clusters during the creation of self-assembled submonolayers. This clustering is attributed to strong interactions between the bismuth (Bi) center and the nitrogen atom in the -CN group of adjacent molecules. Examination of the influence of -NH2 and -CN anchoring groups on junction conductance revealed that, despite a stronger binding energy between the -NH2 group and gold, the conductance per molecular unit (i.e., molecule for the -NH2 group and cluster for the -CN group) is higher with the -CN anchoring group. Further analysis showed that an increase in the number of -CN groups from one to three within the junctions leads to a decrease in conductance while increasing the size of the cluster. This demonstrates the significant effects of different anchoring groups and the impact of varying the number of -CN groups on both the charge transport and cluster formation. This study highlights the importance of selecting the appropriate anchoring group in the design of molecular junctions. Additionally, controlling the size and formation of clusters can be a strategic approach to engineering charge transport in molecular junctions.

Photonic/Electronic Material Performance and Application Based on Nanocrystals and Nanostructures.

Electronic, optoelectronic, and optical devices have become integral to the fabric of the modern life, underpinning critical advancements in information technology, energy utilization, biotechnology, environmental monitoring, and nanotechnology [...].

Recent Advances in the Synthesis and Application of Vacancy-Ordered Halide Double Perovskite Materials for Solar Cells: A Promising Alternative to Lead-Based Perovskites.

Lead-based halide perovskite materials are being developed as efficient light-absorbing materials for use in perovskite solar cells (PSCs). PSCs have shown remarkable progress in power conversion efficiency, increasing from 3.80% to more than 25% within a decade, showcasing their potential as a promising renewable energy technology. Although PSCs have many benefits, including a high light absorption coefficient, the ability to tune band gap, and a long charge diffusion length, the poor stability and the toxicity of lead represent a significant disadvantage for commercialization. To address this issue, research has focused on developing stable and nontoxic halide perovskites for use in solar cells. A potential substitute is halide double perovskites (HDPs), particularly vacancy-ordered HDPs, as they offer greater promise because they can be processed using a solution-based method. This review provides a structural analysis of HDPs, the various synthesis methods for vacancy-ordered HDPs, and their impact on material properties. Recent advances in vacancy-ordered HDPs are also discussed, including their role in active and transport layers of solar cells. Furthermore, valuable insights for developing high-performance vacancy-ordered HDP solar cells are reported from the detailed information presented in recent simulation studies. Finally, the potential of vacancy-ordered HDPs as a substitute for lead-based perovskites is outlined. Overall, the ability to tune optical and electronic properties and the high stability and nontoxicity of HDPs have positioned them as a promising candidate for use in photovoltaic applications.

Advancements in Perovskite Nanocrystal Stability Enhancement: A Comprehensive Review.

Over the past decade, perovskite technology has been increasingly applied in solar cells, nanocrystals, and light-emitting diodes (LEDs). Perovskite nanocrystals (PNCs) have attracted significant interest in the field of optoelectronics owing to their exceptional optoelectronic properties. Compared with other common nanocrystal materials, perovskite nanomaterials have many advantages, such as high absorption coefficients and tunable bandgaps. Owing to their rapid development in efficiency and huge potential, perovskite materials are considered the future of photovoltaics. Among different types of PNCs, CsPbBr3 perovskites exhibit several advantages. CsPbBr3 nanocrystals offer a combination of enhanced stability, high photoluminescence quantum yield, narrow emission bandwidth, tunable bandgap, and ease of synthesis, which distinguish them from other PNCs, and make them suitable for various applications in optoelectronics and photonics. However, PNCs also have some shortcomings: they are highly susceptible to degradation caused by environmental factors, such as moisture, oxygen, and light, which limits their long-term performance and hinders their practical applications. Recently, researchers have focused on improving the stability of PNCs, starting with the synthesis of nanocrystals and optimizing (i) the external encapsulation of crystals, (ii) ligands used for the separation and purification of nanocrystals, and (iii) initial synthesis methods or material doping. In this review, we discuss in detail the factors leading to instability in PNCs, introduce stability enhancement methods for mainly inorganic PNCs mentioned above, and provide a summary of these approaches.

Effect of individual or combination of dietary betaine and glycine on productive performance, stress response, liver health, and intestinal barrier function in broiler chickens raised under heat stress conditions.

The current experiment was conducted to investigate the effect of individual or combination of dietary betaine (Bet) and glycine (Gly) on productive performance, stress response, liver health, and intestinal barrier function in broiler chickens raised under heat stress (HS) conditions. A total of four hundred twenty 21-d-old Ross 308 broiler chickens were randomly allotted to 1 of 5 dietary treatments with 7 replicates. Birds in treatment 1 were raised under the thermoneutral condition (TN; 23 ± 0.6°C). Birds in other 4 treatment groups were subjected to a cyclic HS by exposing them to 32 ± 0.9°C for 8 h/d (from 09:00 to 17:00 h) and 28 ± 1.2°C for the remaining time for 14 d. Birds were fed a basal diet in TN condition (TN-C) and one group in HS conditions (HS-C), whereas other birds raised under HS conditions were fed the basal diet supplemented with 0.20% Bet (HS-Bet), 0.79% Gly (HS-Gly), or their combination (0.20% Bet + 0.79% Gly; HS-Bet+Gly). Results indicated that birds in HS-Bet, HS-Gly, or HS-Bet+Gly treatment had higher (P < 0.05) final BW and BW gain, but lower (P < 0.05) feed conversion ratio (FCR) than those in HS-C treatment. However, values for improved final BW, BW gain, and FCR by dietary treatments were lower (P < 0.05) than those measured in TN-C treatment. Under HS conditions, birds in HS-Bet, HS-Gly, or HS-Bet+Gly treatment had lower (P < 0.05) heterophil to lymphocyte ratio than those in HS-C treatment. Birds in HS-Gly or HS-Bet+Gly treatment had higher (P < 0.05) villus height and goblet cell number than birds in HS-C treatment. Intestinal permeability was higher (P < 0.05) in all HS-treatment groups than in TN-C treatment, but it was not affected by dietary treatment. In conclusion, individual supplementation of 0.20% Bet or 0.79% Gly in diets alleviates the negative effect of HS in broiler chickens. However, the synergistic effect of the combination of 0.20% Bet and 0.79% Gly in broiler diets seems lower than expected.

Defect Passivation via Isoxazole Doping in Perovskite Solar Cells.

To improve perovskite solar cell (PSC) performance, which is deeply related to perovskite layer quality, researchers have explored numerous strategies. Additive doping into perovskite precursors has been widely used to improve the PSC performance. In this study, we used isoxazole-a Lewis-base small molecule-as an additive for the CH3NH3PbI3 (MAPbI3) precursor and explored how isoxazole effectively passivates defects in the perovskite structure. We found that isoxazole interacted with undercoordinated Pb2+ ions from an X-ray photoelectron spectroscopy survey and verified that isoxazole doping improved the device performance. When the optimized concentration of isoxazole was doped in the MAPbI3 precursor, the power conversion efficiency increased from 15.6 to 17.5%, with an improved fill factor and short-circuit current density. In addition, an isoxazole-doped device sustained 94% of its initial performance after 8 days under ambient air conditions (10 ± 5 RH %, 25 °C), whereas a device without isoxazole doping only maintained 64% of its initial performance.

Unraveling the Structural Instability of Li(Ni0.80 Co0.15 Al0.05 )O2 as a Cathode Material Due to Operating a Li-ion Battery.

The change of the crystal structure for Li(Ni0.80 Co0.15 Al0.05 )O2 as a cathode material in a Li-ion battery is traced. During charging and discharging, the crystallographic change of Lix (Ni0.80 Co0.15 Al0.05 )O2 (x ≈ 1.0-0.25) is confirmed with in situ X-ray diffraction, an electrochemical measurement, and the density functional theory calculation. Li atoms after cycling do not completely return to the initial state and defects in the Li-layer generate about 5%. The effect of defects in the Li-layer reveals the transformation of crystal structure and the change of lattice constants. Upon increasing the temperature, the instability of Li0.95 (Ni0.80 Co0.15 Al0.05 )O2 is clearly shown as the movement of transition metals using X-ray and neutron diffraction. The crystallographic values dramatically change upon increasing from 373 to 423 K, but linearly vary upon decreasing temperature. Furthermore, the result of the calculation demonstrates that the possible atom for mixing is Ni. The evolution of magnetic properties explicitly certifies the atomic movement that gives rise to a spin-glass state through the induction of ferromagnetism. In conclusion, defects are created in crystal structure during operation of the Li-ion battery and generate structural instability. The results provide the cause and mechanism of the degradation of cathode material in a Li-ion battery.

Physical Surface Modification of Carbon-Nanotube/Polydimethylsiloxane Composite Electrodes for High-Sensitivity DNA Detection.

The chemical modification of electrode surfaces has attracted significant attention for lowering the limit of detection or for improving the recognition of biomolecules; however, the chemical processes are complex, dangerous, and difficult to control. Therefore, instead of the chemical process, we physically modified the surface of carbon-nanotube/polydimethylsiloxane composite electrodes by dip coating them with functionalized multi-walled carbon nanotubes (F-MWCNTs). These electrodes are used as working electrodes in electrochemistry, where they act as a recognition layer for sequence-specific DNA sensing through π-π interactions. The F-MWCNT-modified electrodes showed a limit of detection of 19.9 fM, which was 1250 times lower than that of pristine carbon/polydimethylsiloxane electrodes in a previous study, with a broad linear range of 1-1000 pM. The physically modified electrode was very stable during the electrode regeneration process after DNA detection. Our method paves the way for utilizing physical modification to significantly lower the limit of detection of a biosensor system as an alternative to chemical processes.

Synergistic Effects of Self-Assembled Monolayers in Solution-Processed 6,13-Bis(triisopropylsilylethynyl)Pentacene Transistors.

Organic semiconductors are highly interface-sensitive, and therefore chemical functionalization using self-assembled monolayers (SAMs) is often adopted to tailor their properties. This study clarifies the synergistic effects of electrode and dielectric SAMs on the behavior of solution-processed organic field-effect transistors (OFETs). Utilization of a self-consistent device model enables a physically robust treatment of the measured electrical characteristics of the OFETs, thus providing highly reliable materials, interface, morphology, and transport parameters. These parameters are further extended and correlated to build a comprehensive picture on trap energy and injection-transport relationship, finally revealing a set of fundamental insights into chemically modified OFETs.

Cesium Doping for Performance Improvement of Lead(II)-acetate-Based Perovskite Solar Cells.

Lead(II)-acetate (Pb(Ac)2) is a promising lead source for the preparation of organolead trihalide perovskite materials, which avoids the use of inconvenient anti-solvent treatment. In this study, we investigated the effect of cesium doping on the performance of Pb(Ac)2-based perovskite solar cells (PSCs). We demonstrate that the quality of the CH3NH3PbI3 perovskite film was improved with increased crystallinity and reduced pinholes by doping the perovskite with 5 mol% cesium. As a result, the power conversion efficiency (PCE) of the PSCs was improved from 14.1% to 15.57% (on average), which was mainly induced by the significant enhancements in short-circuit current density and fill factor. A PCE of 18.02% was achieved for the champion device of cesium-doped Pb(Ac)2-based PSCs with negligible hysteresis and a stable output. Our results indicate that cesium doping is an effective approach for improving the performance of Pb(Ac)2-based PSCs.

The Histone Deacetylase Inhibitor (MS-275) Promotes Differentiation of Human Dental Pulp Stem Cells into Odontoblast-Like Cells Independent of the MAPK Signaling System.

The role of dental pulp stem cells (DPSCs) in dental tissue regeneration is gaining attention because DPSCs can differentiate into odontoblasts and other specialized cell types. Epigenetic modification has been found to play an important role in cell differentiation and regulation, among which histone deacetylase (HDAC) is involved in suppressing genes by removing histone acetyl groups. The use of HDAC inhibitor to control this is increasing and has been widely studied by many researchers. This study aimed to induce differentiation by causing epigenetic changes in odontoblast-related genes and the MAPK signaling pathway in human dental pulp stem cells. Western blot and immunofluorescence staining showed increased expression of DMP-1, ALP, DSPP, and RUNX2 compared to the control. However, activation of the MAPK signaling system was similar to but slightly different from the expression of odontoblast-related proteins. After 3 days, as shown by MTT and LDH assays, proliferation decreased overall, but cytotoxicity decreased at only a specific concentration. We confirmed that there was no change in mRNA expression of caspase 3 or 9 using real-time PCR. In addition, flow cytometry analysis confirmed that differentiation occurred due to the decrease in the expression of the CD73 and CD146. Although overall proliferation was reduced due to the G2/M inhibition of the cell cycle, the expression of BCL-2 protected the cells from cell death. Overall, cell proliferation decreased in response to MS-275, but it did not induce cytotoxicity in 5 nM and 10 nM concentration and induces differentiation into odontoblast-like cells.

Pigmentation Effect of Rice Bran Extract in Hair Follicle-Like Tissue and Organ Culture Models.

BACKGROUND: Melanogenesis is a biological process resulting in the production of melanin pigment, which plays an important role in the prevention of sun-induced skin injury and determines the hair and skin color. Melanin has the ability to block ultraviolet radiation and scavenge free oxygen radicals, thus protecting the skin from their harmful effects. Agents that increase melanin synthesis in melanocytes may reduce the risk of photodamage and skin cancer. Hence, various approaches have been proposed to increase the synthesis of melanin. METHODS: The current study aimed to develop a three-dimensional hair follicle-like tissue (HFLT) model with human dermal papilla, melanocytes, and outer root sheaths cells. This model showed enhanced melanogenesis-related protein expression after rice bran ash extract (RBE) treatment. Next, we investigated the melanogenic effect of RBE in the HFLT and compared the results to those of hair follicle (HF) organ culture model. RESULTS: RBE was found to significantly increase the expression of microphthalmia-associated transcription factor, a key transcription factor involved in melanin production, in both HFLT and organ culture models. Results showed that melanogenesis-related protein expression levels were higher in the RBE group compared to those in the control group. Similar results were obtained by immunohistochemistry. CONCLUSION: Our data suggested that RBE promotes melanin biosynthesis. Taken together, this simple in vitro HFLT model system has the potential to provide significant insights into the underlying molecular mechanisms of HF melanogenesis, and hence can be used for controlled evaluation of the efficacy of new materials for melanogenesis.

Extremely Low-Frequency Electromagnetic Fields Increase the Expression of Anagen-Related Molecules in Human Dermal Papilla Cells via GSK-3ß/ERK/Akt Signaling Pathway.

Despite advances in medical treatments, the proportion of the population suffering from alopecia is increasing, thereby creating a need for new treatments to control hair loss and prevent balding. Human hair follicle dermal papilla cells (hDPCs), a type of specialized fibroblast in the hair bulb, play an essential role in controlling hair growth and in conditions like androgenic alopecia. This study aimed to evaluate the intensity-dependent effect of extremely low-frequency electromagnetic fields (ELF-EMFs) on the expression of anagen-related molecules in hDPCs in vitro. We examined the effect of ELF-EMF on hDPCs to determine whether activation of the GSK-3ß/ERK/Akt signaling pathway improved hDPC activation and proliferation; hDPCs were exposed to ELF-EMFs at a frequency of 70 Hz and at intensities ranging from 5 to 100 G, over four days. Various PEMF intensities significantly increased the expression of anagen-related molecules, including collagen IV, laminin, ALP, and versican. In particular, an intensity of 10 G is most potent for promoting the proliferation of hDPC and expression of anagen-related molecules. Moreover, 10 G ELF-EMF significantly increased ß-catenin and Wnt3α expression and GSK-3ß/ERK/Akt phosphorylation. Our results confirmed that ELF-EMFs enhance hDPC activation and proliferation via the GSK-3ß/ERK/Akt signaling pathway, suggesting a potential treatment strategy for alopecia.

Rice Bran Ash Mineral Extract Increases Pigmentation through the p-ERK Pathway in Zebrafish (Danio rerio).

The purpose of the present study is to evaluate the effect of rice bran ash mineral extract (RBM) on pigmentation in zebrafish (Danio rerio). Melanin has the ability to block ultraviolet (UV) radiation and scavenge free oxygen radicals, thus protecting the skin from their harmful effects. Agents that increase melanin synthesis in melanocytes may reduce the risk of photodamage and skin cancer. The present study investigates the effect of RBM on pigmentation in zebrafish and the underlying mechanism. RBM was found to significantly increase the expression of microphthalmia-associated transcription factor (MITF), a key transcription factor involved in melanin production. RBM also suppressed the phosphorylation of extracellular signal-regulated kinase (ERK), which negatively regulates zebrafish pigmentation. Together, these results suggest that RBM promotes melanin biosynthesis in zebrafish.

Highly selective, reusable electrochemical impedimetric DNA sensors based on carbon nanotube/polymer composite electrode without surface modification.

We fabricated a composite of multi-walled carbon nanotube and polydimethylsiloxane and utilized it as an electrode for DNA sensing using electrochemical impedance spectroscopy. Without any surface modification or probe immobilization, often necessary for other electrodes, this electrode also acts as a recognition layer for DNA via π-π interactions between the multi-walled carbon nanotube and DNA. This electrode is easily reusable via a simple cleansing process, because there are no covalently bonded adsorbates on the electrode. Compared to previous DNA detection based on differential pulse voltammetry using a similar electrode, the measurement time was reduced from 1 h to less than 30 min, and the limit of detection (25 pM) was reduced by a factor of more than five. In addition, our system can detect the single-base mismatch between the target and probe. Our results indicate that electrochemical impedance spectroscopy is promising for utilizing the multi-walled carbon nanotube and polydimethylsiloxane electrode as a DNA sensor.

Alcohol based vapor annealing of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) layer for performance improvement of inverted perovskite solar cells.

In this study, we introduced alcohol based vapor annealing of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer for fabricating high-performance inverted perovskite solar cells. Atomic force microscopy measurements and atomistic theoretical simulations indicated that phase separation between PEDOT and PSS was enhanced by this annealing, improving the hole conductivity at the PEDOT:PSS layer. As a result of using methanol, the short-circuit current density improved from 20.7 to 21.6 mA cm-2; consequently, the power conversion efficiency (PCE) improved from 16.1 to 17.3%. However, using ethanol or isopropanol yielded a smaller performance improvement. The PCEs of the best sample in this study under forward and reverse scans were 17.7 and 18.0%, respectively, indicating that the PSC had a small hysteresis. Our results suggest that alcohol vapor annealing is a simple and effective method of developing high-performance inverted perovskite solar cells.

Carbon nanotube/polymer composite electrodes for flexible, attachable electrochemical DNA sensors.

All-solution-processed, easily-made, flexible multi-walled carbon nanotube (MWCNT)/polydimethylsiloxane (PDMS)-based electrodes were fabricated and used for electrochemical DNA sensors. These electrodes could serve as a recognition layer for DNA, without any surface modification, through π-π interactions between the MWCNTs and DNA, greatly simplifying the fabrication process for DNA sensors. The electrodes were directly connected to an electrochemical analyzer in the differential pulse voltammetry (DPV) and cyclic voltammetry (CV) measurements, where methylene blue was used as a redox indicator. Since neither functional groups nor probe DNA were immobilized on the surfaces of the electrodes, the sensor can be easily regenerated by washing these electrodes with water. The limit of detection was found to be 1.3 × 10(2)pM (S/N=3), with good DNA sequence differentiation ability. Fast fabrication of a DNA sensor was also achieved by cutting and attaching the MWCNT-PDMS composite electrodes at an analyte solution-containable region. Our results pave the way for developing user-fabricated easily attached DNA sensors at low costs.

Bimetal coated optical fiber sensors based on surface plasmon resonance induced change in birefringence and intensity.

We present a surface plasmon resonance (SPR) based multimode fiber sensor with non-golden bimetallic coating. Our detection scheme used, which is capable of measuring the combined effects of SPR-induced birefringence and intensity changes, supported the minimum resolvable refractive index (RI) of 5.8 × 10(-6) RIU with the operating RI range of 0.05 to be experimentally obtained at a single wavelength (632.8 nm) without non-spectroscopic techniques. The asymmetric profile of the thickness of the bimetal coating on the fiber core together with the inherent range of incidence angle for multimode propagation also contributed to the wide operating range. The SPR fiber device with the detection scheme demonstrated will be likely to be developed as a real-time label-free and highly sensitive diagnostic device of a wide operating range for biomedical and biochemical applications in a portable format.

Sequence-specific detection of DNA using functionalized graphene as an additive.

We developed a simple and sensitive method for sequence-specific DNA detection using functionalized graphene (FG) and methylene blue (MB). Target DNA with a specific sequence was identified by differential-pulse voltammetry, which produces a change in the redox currents of the incorporated MB. FG played a critical role in enhancing the sensitivity of DNA detection and reduced the concentration of MB substantially near the electrodes when the sequence of the target DNA was not complementary to that of the probe by adsorbing the single-stranded DNA with the bound MB, and sinking. Our system could detect even single base-pair mismatches between the target and probe. Fabricating this system does not involve a laborious probe-immobilization process and is considerably simpler than fabricating graphene-electrode-based DNA sensors.