HOMO-LUMO Energy Levels Research Articles

Molecular architecture of a novel indoline-fused chromenylium-cyanine probe carrying methionine biomolecule for ultrasensitive analyzing Hg2+ ion in real samples

In this study, by decorating the chromenylium-cyanine structure with an indoline ring, a new sensor platform CSI with a highly rigid structure and improved photophysical properties was developed for the first time. The CSI platform was modified with glyoxal and L-methionine methyl ester to produce a new NIR, ratiometric, and switch-on probe (CIME). This probe is biocompatible, water soluble, and has a specific binding mode for Hg2+ ion selectivity. The crystal structure of CSI was determined by x-ray crystallography, and its electronic characteristics, including HOMO-LUMO energy levels were determined by quantum mechanical calculations. CIME is the first instance of an indoline-fused chromenylium-cyanine used for quantification of trace level of Hg2+ in both the living cells and the environment. The new probe has a high level of selectivity and sensitivity for Hg2+ in aqueous media, with broad linear ranges (0–300 μM for UV-Vis and 0–225 μM for fluorescence). It has a rapid response time of 30 seconds, and UV-Vis and fluorescence detection limits of 7.4 ng/mL and 0.13 ng/mL, respectively. Probe quantitatively detected Hg2+ in real samples using UV-Vis, fluorescence spectrophotometry and a smartphone. The interaction between CIME and Hg2+ was verified by FTIR, HRMS and DFT calculations. Furthermore, the ability of CIME to sense Hg2+ in living cells was confirmed in both MCF-7 cells and 3T3 cells.

Impact of voltage and frequency on electrical characteristics of MIS capacitors with triphenylamine layer

This study examines the effect of triphenylamine (TPA) interlayers on the electrical properties of Al/TPA/p-Si metal-interlayer/insulator material-semiconductor (MIS) capacitors. Using Gaussian software, TPA molecular structure was optimized, and HOMO-LUMO energy levels were simulated. Capacitance-conductance-voltage (C-G-V) measurements were performed at room temperature over −4 V to +4 V and 50 kHz–700 kHz. AFM and SEM analysis showed TPA films were smooth with a uniform thickness of about 178 nm. The C-V characteristics revealed a frequency-dependent decrease in capacitance, indicating a continuous distribution of interface states. Barrier height (ΦB) increased from 0.305 eV at 50 kHz to 0.655 eV at 700 kHz, while the active interface trap density (Dit) decreased from 6.73 × 1012 eV−1 cm−2 to 3.23 × 1011 eV−1 cm−2. Additionally, the accumulating region exhibited low series resistance values (between 6.88 and 8.44 Ω). These results suggest that TPA thin films are effective for MIS capacitors.

A Magnesium Organic Framework Fluorescent Sensor for Selective Detection of Nitrofuran Antibiotics and Inorganic Pollutants

ABSTRACTA novel 3D magnesium‐based metal organic framework (Mg‐MOF) has been solvothermally synthesized using 5‐(pyridin‐4‐yl)isophthalic acid. The ligand has demonstrated to preserve two types of coordination modes depending on the connection mode of the pyridine group. The uncoordinated pyridine groups provide Lewis base sites (LBSs), whereas the coordinated ones promote to form a rarely reported eight‐connected tetranuclear Mg clusters. Benefiting from the multinuclearity with high number of connections, the framework keeps good performance of high thermal stability until 500°C. Furthermore, the framework exhibits potential open metal sites (OMSs) benefiting from the terminal coordinated water groups of the metal clusters. Owing to the abundant active sites, the Mg‐MOF exhibits good sensitivity to nitrofuran antibiotics and Cr2O72−, with high KSV (at 104 M−1 level) and low limit of detection (LOD) values (∼10−6 M). Density functional theory (DFT) investigation reveals that the interchange of the HOMO–LUMO energy levels of the framework and antibiotics is responsible for the sensing activity. In addition, the Mg‐MOF is greatly recyclable in five cycles while maintaining the structural rigidity and sensing activity, making it a promising luminescence probe material.

DFT/TD-DFT study of novel triphenylamine-based dyes with azo moieties and π-spacer variations for enhanced dye-sensitized solar cell performance

This study involves a computational analysis of new D-π-A dyes obtained from triphenylamine (TPA), which contain various azo-dye components. The structural, molecular, electrical, and optical properties of these dyes were computed using Density Functional Theory (DFT) and Time-Dependent DFT, utilizing the B3LYP/6–31 G model. Our research specifically aimed to investigate the effects of incorporating different azo dye constituents in the para position of two phenyl groups of TPA. The results indicate that these alterations lead to notably broadened and red-shifted absorption spectra, as well as improved optoelectronic properties that are subject to additional tuning through the manipulation of the π-spacer. The excitation energies and HOMO-LUMO energy levels that have been estimated indicate the presence of effective electron injection and dye regeneration mechanisms. The results concerning the nonlinear optical (NLO) properties suggest that these dyes are likely to demonstrate superior performance in NLO applications. The factors encompassed in this study consist of light-harvesting efficiency (LHE), open-circuit photovoltage (VOC), electron injection driving force (ΔGinj), dye regeneration driving force (ΔGreg), excited state lifetime (τ) and reorganization energy (λtotal), which has a strong correlation with the electrical current density in a short-circuit (JSC) and DSSC's overall effectiveness. This scientific attempt contributes to the systematic advancement of efficient dyes, demonstrating the possibility for enhanced efficiency in DSSCs. Further validation of computational forecasts and advancement of renewable energy technology necessitate future experimental synthesis and testing.

Metal-free phenothiazine dyes with alkoxy chains modified at different position for dye-sensitized solar cells

Long alkyloxy or alkoxyphenyl chains are commonly introduced to organic dye sensitizers in dye-sensitized solar cells (DSSCs) to inhibit the aggregation of sensitizer on the TiO2, thereby minimizing charge recombination. Here, we synthesized four D-D-π-A sensitizers (TP-C6, TP-PhOC6, C6O-TP-C6, C6O-TP-PhOC6), that feature alkyl-/alkoxyphenyl- moiety in phenothiazine (PTZ) donor’s N-position, and either alkoxy or no alkoxy groups in triphenylamine (TPA) auxiliary donor. Then, their photophysical, electrochemical and DSSCs properties were investigated. The UV-Vis and electrochemical studies revealed that all four dyes exhibited good light absorption ability and appropriate HOMO-LUMO energy levels. The introduction of alkoxy at the donor or auxiliary donor can result in a significant redshift in absorption. Among them, TP-PhOC6, which incorporates an alkoxy phenyl group at the N-position of PTZ and lacks alkoxy in TPA, induces a greater redshift in ICT absorption with strong absorption intensity. Additionally, in TP-PhOC6 based DSSC, mitigated charge recombination was observed. As a result, this device exhibited the strongest and widest IPCE spectrum, the highest Jsc (12.77 mA/cm²) and Voc (0.85 V), leading to the highest PCE (6.59 %).

Theoretical Investigation of Transport Properties of X-doped (X = Cl, P, N) Graphene Quantum Dots Layer Adsorbed with Ammonia Molecule Using Non-Equilibrium Green’s Function

This study investigates the various transport properties, including Density of States (DOS), Transmission Coefficient, Current-Voltage Characteristics (I-V), and HOMO-LUMO energy levels, of X-doped (X = Cl, P, N) graphene quantum dot (GQD) layers with adsorbed ammonia molecules using density functional theory and non-equilibrium Green's function techniques. Our findings revealed the profound influence of different doping and adsorption scenarios on the transport properties of GQD layers. Specifically, chlorine doping leads to notably stronger resonance peaks, resulting in enhanced conductivity of the GQD layer. This effect is less pronounced for P-doped and N-doped GQDs, which exhibit minimal changes in conductance capability. Importantly, we observed a prominent interaction between ammonia molecules and chlorine-doped GQD layers. The HOMO and LUMO energy levels exhibit double degeneracy, significantly impacting edge passivation and the finite dimensions of GQDs, consequently reducing the energy gap. As a result, chlorine-doped GQD layers with adsorbed ammonia molecules exhibit increased energy levels and stronger current characteristics compared to P-GQDs and N-GQDs. HOMO and LUMO are doubly degenerated which has a clear effect on edge passivation as well as the finite size of GQDs and reduces energy gap. Therefore, more energy level and stronger current is available for chlorine doped graphene quantum dots layer with adsorbed ammonia molecule than P-GQDs and N-GQDs. Our theoretical finding highlighted the significant features of edge passivation, doping effect and adsorption of ammonia molecule onto graphene quantum dots layer. Our theoretical analysis highlighted key features encompassing edge passivation, doping effects, and ammonia molecule adsorption on GQD layers. These insights not only develop our fundamental understanding of these systems but also hold promise for novel applications that harness their distinct electronic properties.

Synthesis and Multifaceted Exploration of 4-Phenylpiperidin-4-ol Substituted Pyrazole: Photophysical Insights with Biological Activity

Abstract In this study, we successfully synthesized a pyrazole derivative, specifically 4-phenylpiperidin-4-ol substituted pyrazole (CHP), through the reaction of Grignard reagents in combination with pyrazole. This newly synthesized molecule was subjected to a comprehensive evaluation for both its photophysical and biological applications. Notably, CHP exhibited promising invitro antifungal and antibacterial activities, primarily attributed to the presence of the 4-phenylpiperidin-4-ol moiety and resulting component contributed to an enhanced absorption rate of lipids, thereby improving the pharmacological activity of CHP. This correlation between structure and function was further supported by the outcomes of structure-activity relationship studies. Additionally, we conducted in silico studies to examine the molecular interactions of the synthesized molecule with key proteins, including DNA Gyrase, Lanosterol 14 α-demethylase, and KEAP1-NRF2. The results unveiled robust binding interactions at specific sites within these proteins, indicating potential therapeutic relevance. Furthermore, the photophysical properties of the synthesized compounds were thoroughly investigated using the ab-initio technique. This involved the determination of ground state optimization and HOMO-LUMO energy levels, all calculated with the DFT-B3LYP-6-31G(d) basis set. The assessment of the theoretically estimated HOMO-LUMO value provided insights into the global chemical reactivity descriptors, revealing that the synthesized molecule boasts a highly electronegative and electrophilic index. Taken together, our findings suggest that pyrazole derivatives with 4-phenylpiperidin-4-ol substitutions exhibit promising applications in both photophysical and biological contexts.

Novel palladium nanoparticles/4-aminophenol functionalized nitrogen-doped graphene quantum dots-based nanocomposite electrochemical sensor: Synthesis, characterization, capacitance, and dopamine sensing

In this study, an ultrasensitive electrochemical sensor based on palladium nanoparticles/4-aminophenol functional nitrogen-doped graphene quantum dots (PdNPs/4AP N-GQDs) composite was fabricated to detect dopamine (DA). The sensor was characterized by FTIR, UV–Vis, TEM, EDX, and XRD methods. The electrochemical analysis of the nanocomposite modified glassy carbon electrode (GCE) was conducted by cyclic voltammetry (CV). HOMO-LUMO energy levels and band gap energy was calculated from cyclic voltammograms, and the band gap energy was found to be small at 0.06 eV. The electrode reaction properties of dopamine on this developed ultrasensitive electrode were investigated by CV and differential pulse voltammetry (DPV), which showed that the electrode had electrocatalytic activity for dopamine sensing. Moreover, the developed electrode exhibited good sensitivity and improved performance, and the linear calibration curve for dopamine was calculated to have a LOD (limit of detection) of 21 pM in the range of 250 pM to 10 nM. Finally, the selectivity of the GQDs nanocomposite modified GCE towards dopamine was studied in the presence of several bioactive compounds with inhibitory effects. In addition, the specific capacitance of the nanocomposite material at 5 mV s−1 was found to be as high as 0.777F g−1. Furthermore, the dopamine selectivity of the sensor among some organic and inorganic interfering bioanalytes was investigated and the sensor was found to have excellent DA selectivity despite the bioanalytes.

DFT and TD-DFT Studies of D-π-A Organic Dye Molecules with Different Spacers for highly Efficient Reliable Dye Sensitized Solar Cells.

This study focuses on six D-π-A systems, utilizing diverse π-spacers as bridges. Comprehensive analysis through Density Functional Theory (DFT) and Time-dependent Functional Theory (TD-DFT) methods at B3LYP using 6-31G (d.p) basis set explores geometrical, electrical, optical, photovoltaic, and absorption properties. EHOMO, ELUMO, and energy gap (Egap), for all of these dyes have been determined and discussed using ground state optimization. TD-DFT calculates optical properties, unveiling enhanced excitation energies and HOMO-LUMO energy levels, indicative of improved electron injection and dye regeneration processes. Examination of energy gap, open-circuit voltage (VOC), free energy change (ΔGinject), light harvesting efficiency (LHE), and absorption spectra reveals D4 dye's lower Egap and robust absorption in the visible spectrum. Molecular tailoring emerges as a promising technique for optimizing D-π-A sensitizer design, offering potential advancements in DSSCs applications.

Perylene Diimide-Based Dimeric Electron Acceptors with Molecular Conformations for Perovskite Solar Cells.

This paper reports five novel PDI dimer type electron transport materials (ETMs) employing o-indoloquinoxaline (o-Iq), m-indoloquinoxaline (m-Iq), and cibalackrot (Ci) groups as the core building blocks and presents the twisted structures of PDI dimers coded as PDI-NHR-o-Iq, PDI-o-Iq, PDI-NHR-m-Iq, PDI-m-Iq and PDI-NHR-Ci dyes (see Scheme 1 and 2). We have systematically compared their photophysical, electrochemical, and optoelectronic properties with respect to the reference dye (2PDI-NHR), which is directly connected of two PDI planes. Their calculated HOMO-LUMO energy levels are sufficient for charge transfer to the perovskite material so that structure-photovoltaic performance relationship of synthesized ETM dyes can be evaluated. When the binding position of indoloquinoxaline group between PDI rings are changed from o- to m- positions, most of the photophysical and electrochemical properties of PDI dimer are dramatically changed, finally improving the photovoltaic performances.

Photophysical and Physiochemical Study of New Pyrenyl Chalcone Derivatives as Sensitizers for Organic Solar Cells

Three pyrenyl chalcone derivatives namely, PCH1, PCH2, and PCH3 were synthesized by utilizing the Claisen-Schmidt condensation technique. Compound PCH1 was successfully recrystallized via the slow evaporation technique. To determine and refine the crystal structure, the single crystal is subjected to X-ray diffraction (XRD) analysis. Crystal packing reveals that intermolecular C-H···O interactions bind molecules in compound PCH1 in a head-to-head arrangement. Intramolecular charge transfer (ICT) between molecules has improved as a result of the compound’s C-H···O contacts. The compounds were then characterized using UV-Vis spectroscopy where all compounds have an energy gap that is within the low range, ranging from 2.89 to 2.94 nm. Furthermore, the HOMO-LUMO energy levels of the pyrenyl chalcones were examined by conducting CV analysis. The energy levels of the compounds essentially lie between the conduction band of TiO2 and the redox potential ( I − / I 3 − ) of the electrolyte. FESEM and EDX analyses were utilized in solar cell performance investigations to examine the surface topography and elemental mapping of the pyrenyl compound on the TiO2 layer, correspondingly. Compound PCH2 emerges as the most effective dye-sensitizer in DSSC applications due to the anchoring of strong substituent groups in the compound, even though all three compounds demonstrated suitability as dye-sensitizer materials.

Effect of metal (Cr, Sr, Ag, Cu) doping on the performance of lead-free RbSnI3 based perovskite solar cells: A theoretical approach

Perovskite solar cells based on lead have witnessed unprecedented growth over the past decade, achieving an impressive power conversion efficiency (PCE) of 26.1%. However, lead toxicity remains a concern for commercialization. In order to resolve the matter, scientists have been investigating alternative materials; in this context, rubidium-based lead-free perovskites like RbSnI3 may be a promising alternative because it has a high optical conductivity and absorption coefficient. Density Functional Theory (DFT)-based first-principles studies are used in this work to examine the effect of metal doping (specifically Cr, Sr, Ag, and Cu) on the optoelectronic and structural characteristics of orthorhombic RbSnI3 perovskite. In addition, we conducted a comprehensive study to investigate the impact of metal doping on the formation energy, structural stability, and HOMO–LUMO energy levels of RbSnI3 perovskite. Introducing transition metal cations (Cr2+, Ag+, and Cu+) at the Rb site results in a flat band in the conduction band region, transforming the RbSnI3’s indirect band gap into a direct one and significantly affecting the optoelectronic properties. The DFT results are then integrated into the Solar Cell Capacitance Simulator (SCAPS-1D) to estimate the effectiveness of the modeled device. The Cu-doped RbSnI3 device exhibits the highest PCE of 20.2%. Furthermore, Ag and Cu doping in RbSnI3 increases bond length, which reduces exciton binding energy and helps with charge carrier generation.

A comprehensive investigation of ethyl 2-(3-methoxybenzyl) acrylate substituted pyrazolone analogue: Synthesis, computational and biological studies

In this study, we successfully synthesized ethyl 2-(3-methoxybenzyl) acrylate-substituted pyrazolones derivative (EMH) through the reaction of Baylis-Hillman acetate with pyrazolones. We conducted comprehensive screenings to evaluate its invitro antifungal, antibacterial, and antioxidant properties. The molecule demonstrated notable in vitro antifungal and antibacterial activities attributed to the presence of anisole, enhancing absorption rates through increased lipid solubility and improving pharmacological effects. Structure-activity relationship (SAR) studies supported these findings. Additionally, insilico studies delved into the molecular interactions of the synthesized molecule with DNA Gyrase, Lanosterol 14 alpha demethylase, and KEAP1-NRF2 proteins, revealing strong binding interactions at specific sites. Furthermore, we employed ab-initio techniques to theoretically estimate the photophysical properties of the compounds. Ground state optimization, dipole moment, and HOMO-LUMO energy levels were calculated using the DFT-B3LYP-6-31G(d) basis set. The theoretical HOMO-LUMO values indicated high electronegativity and electrophilicity index. NBO analysis confirmed the presence of intermolecular ON...H hydrogen bonds resulting from the interaction of the lone pair of oxygen with the anti-bonding orbital. Overall, our results suggest that anisole-substituted pyrazolones derivatives exhibit promising applications in both photophysical and biological domains.

A Quantum Chemical Investigation on Structural, Spectroscopic and Nonlinear Optical properties of an Organic Molecule Serotonin

Serotonin, a neurotransmitter known for promoting feelings of happiness and optimism, was the subject of theoretical studies conducted using Gaussian software. In these experiments, the 6-311++G/B3LYP basis set was employed. The finite-field-based B3LYP/6-311++G (d,p) approach was used to compute the first-order hyper polarizability and associated properties of this chemical system. Additionally, a Natural Bond Orbital (NBO) analysis was conducted to assess the molecule's stability, taking into account hyper conjugative interactions and charge delocalization. Additionally, HOMO-LUMO energy levels were computed to assess whether a chemical exhibits electrophilic or nucleophilic characteristic. TD-DFT simulations were conducted to examine the electrical and optical characteristics of the material, including absorption wavelengths and excitation energy. Subsequently, the chemical compound's electrophilic or nucleophilic nature was determined by calculating the molecular electrostatic potential (MEP).

Conjugation through Si-O-Si bonds, silsesquioxane (SQ) half cage copolymers, extended examples via SiO0.5/SiO1.5 units: multiple emissive states in violation of Kasha's rule.

We previously reported that phenyl- and vinyl-silsesquioxanes (SQs), [RSiO1.5]8,10,12 (R = Ph or vinyl) functionalized with three or more conjugated moieties show red-shifted absorption- and emission features suggesting 3-D conjugation via a cage centered LUMOs. Corner missing [PhSiO1.5]7(OSiMe3)3 and edge opened, end capped [PhSiO1.5]8(OSiMe2)2 (double decker, DD) analogs also offer red shifted spectra again indicating 3-D conjugation and a cage centered LUMO. Copolymerization of DD [PhSiO1.5]8(OSiMevinyl)2 with multiple R-Ar-Br gives copolymers with emission red-shifts that change with degree of polymerization (DP), exhibit charge transfer to F4TNCQ and terpolymer averaged red-shifts suggesting through chain conjugation even with two (O-Si-O) end caps possibly via a cage centered LUMO. Surprisingly, ladder (LL) SQ, (vinylMeSiO2)[PhSiO1.5]4(O2SiMevinyl) copolymers offer emission red-shifts even greater for analogous copolymers requiring a different explanation. Here we assess the photophysical behavior of copolymers of a more extreme SQ form: the half cage [PhSiO1.5]4(OSiMe2Vinyl)4, Vy4HC SQs. We again see small red-shifted absorptions coupled with significant red-shifted emissions, even with just a half cage, thus further supporting the existence of pπ-dπ and/or σ*-π* conjugation through Si-O-Si bonds and contrary to most traditional views of Si-O-Si linked polymers. These same copolymers donate an electron to F4TCNQ generating the radical anion, F4TCNQ-. as further proof of conjugation. Column chromatographic separation of short from longer chain oligomers reveals a direct correlation between DP and emission λmax red-shifts as another indication of conjugation. Further, one- and two-photon absorption and emission spectroscopy reveals multiple excited fluorescence-emitting states in a violation of Kasha's rule wherein emission occurs only from the lowest excited state. Traditional modeling studies again find HOMO LUMO energy levels residing only on the aromatic co-monomers rather than through Si-O-Si bonds as recently found in related polymers.

Theoretical investigations of pharmacological activities and solvent effect on structural and nonlinear optical properties of new methyl (E)-3-(2,3,4-trimethoxybenzylidene)dithiocarbazate

A new Schiff base methyl (E)-3-(2,3,4-trimethoxybenzylidene)dithiocarbazate (MTBD) was successfully synthesized by condensation of S-methyldithiocarbazate with 2,3,4-trimethoxybenzaldehyde. The structure of MTBD was confirmed by several spectroscopic techniques such as single crystal X-ray, FTIR, UV–Vis, NMR and mass spectroscopy. To investigate the molecular structure, optoelectronic properties and bioactivity of MTBD, its structure was optimized using the density functional theory (DFT) method on the B3LYP label with a basis set of 6-311++ G (d, p). The optimized structure and the crystal structure showed excellent agreement. Topological studies using a reduced density gradient showed that two monomers are connected by strong hydrogen bonds. Hirshfeld surface analysis revealed the dominance of H⋯H contacts in the molecular system. The solvent effects studied with the IEFPCM model suggested that solvent polarity significantly influences UV absorption, HOMO-LUMO energy level, charge transfer, and nonlinear optical properties. It can be seen that n → π* and π → π* showed a blue shift, and the Egap and NLO properties increased with increasing solvent polarity. Natural bond orbital analysis revealed that MTBD has a 98.0773 % Lewis structure. Molecular docking against the three different cancer receptors 1H7K (colon cancer), 4FM9 (breast cancer) and 1X2J (lung cancer) examined the MTBD ligand as an efficient ligand for the selected targets and showed maximum binding energy to the lung cancer target. Evaluation of drug-likeness and ADMET properties revealed that MTBD has a safer ADMET profile and good oral bioavailability, indicating its effectiveness as a drug candidate.

Studies on 2-((2, 4-dihydroxybenzylidene) amino)-3-phenylpropanoic acid include antimicrobial, antidiabetic, antioxidant, anticancer, hemolysis, and theoretical QSAR

Studies show that microorganisms resistant to numerous antibiotics spread infections, lengthen hospital stays, and increase fatalities. Amplification factors increase the demand for innovative drug-resistant disease-fighting chemicals. This research synthesised the chiral L-phenyl alanine condensed with a 2, 4-dihydroxy benzaldehyde Schiff base for biological efficacy investigations such as antimicrobial, antidiabetic, DPPH free radical, MTT assay against HeLa cells and hemolysis studies after the characterization. Derived Schiff base showed good inhibition against K. pneumoniae (G-ve), Staphylococcus aureus (G + ve), and Candida albicans (Fungus) at a 50 μg/mL concentration. Minimum inhibitory concentration report exists in between 35 ppm and 45 ppm. It also exhibited IC50 concentrations between 138 and 265 μg/mL in the remaining biological studies. This study uses molecular docking with the help of mcule, the CLC drug discovery work bench and visual studio applications to justify the derived compound biological activity and used work related proteins such as 1HSK, 1XCW, 3K0K, 3FDN and 3GEY for docking study. The compound showed a good binding affinity score against the targets with negative values. This study covers drug-likeness using Spartan-14 HOMO-LUMO energy levels and Swiss ADME to determine the molecular properties of the chemical structure. Theoretical outcomes are compared with commercial drugs and observed nearby results. Both theoretical outcomes supported the experimental biological activities and were good coincidence. Communicated by Ramaswamy H. Sarma

A computational study photophysical properties of a series phenothiazine-linked-BODIPY as D-D-π-a photosensitizer unit for photo-induced hydrogen production from water

Phenothiazine-derivatives are designed as sensitizers which covalently-linked with BODIPY for application in a system of dye-sensitized photoelectrochemical cells (DSPECs). A series of phenothiazine-linked-BODIPY as D-D-π-A chromophore have been investigated by a computational approach for studying the capability of the photosensitizers for application in photoinduced water splitting hydrogen production in DSPECs. The geometries of sensitizers at the ground state and excited state were optimized by the CAM-B3LYP/6-31G (d,p) level method. The theoretical study has been done in order to investigate the photophysical properties such as absorption profile, HOMO-LUMO energy and surface plots of the photosensitizer. The result of calculation for HOMO-LUMO energy level of each dyes showed that the LUMO energy are ranging more than -2.8 - (-2.86) eV which is higher than -4.0 eV of conduction band of TiO2 as semiconductor in DSPEC, meaning that all these dyes could be used as photosensitizers in DSPECs. In addition, the oscillator strength data of each dyes showed the dyes have absorption profile in visible region, meaning the dyes could harvest higher intensity of sunlight to induce water splitting reaction to produce hydrogen.

Influence of bulky peripheral substituents on subphthalocyanine derivatives: Implications for photocatalytic and photoelectrochemical hydrogen production

A series of novel subphthalocyanine (SubPc) derivatives with bulky electron-donating substituents were synthesized for visible light-induced photocatalytic and photoelectrochemical hydrogen production. SubPc derivatives were decorated with bulky thiophenoxy (coded SubPc 1–2) and phenoxy (coded SubPc 3–4) substituents to compare the influence of the nature of the peripheral bulky substituents on the photophysical and photocatalytic activity of SubPc. The highest photocatalytic performance was obtained from SubPc 4, having diphenyl phenoxy substituents with an H2 production rate of 7.233 mmol g-1h−1. The photocatalytic hydrogen evolution activities of all SubPc sensitized TiO2 photocatalysts enhanced approximately four times in the presence of Pt co-catalyst. The photocatalysts showed remarkable long-term stability and reproducibility of H2 evolution over 24-hour irradiation. SubPc 4-based photocatalytic system reached a considerable catalytic activity with the H2 production of 16.022 mmol g−1 and a turnover number (TON) value of 34,089 for 24 h irradiation. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) studies were carried out to better understand the photocatalytic abilities of SubPc derivatives and develop a symbiotic connection with experimental investigations. The results highlight the importance of peripheral substituents in modifying electron density, dipole moment, and HOMO-LUMO energy levels and improving SubPc derivative light-harvesting performance. The presence of 2,6-diisopropyl on SubPc derivatives (SubPc 2 and 4) caused a significant change in the properties, resulting in favourable electron transport characteristics and, therefore, improving photocatalytic performance. Furthermore, the incorporation of TiO2, as shown in SubPc 1@TiO2 and SubPc 2@TiO2, resulted in a modest reduction in chemical hardness, implying increased charge transfer inside the molecule and, as a consequence, enhancing its efficacy as a sensitizer. These theoretical discoveries provide a solid foundation for the customized design and optimization of SubPc derivatives for effective photocatalytic applications.

Improvement the formaldehyde sensing and detection through Pt-doped graphdiyne monolayer: Quantum chemical study

One of the commonly employed chemical feedstocks is formaldehyde (CH2O), which has diverse applications in many fields. However, CH2O might have detrimental effects on human because of its toxicity. Hence, it is of utmost significance to effectively monitor and detect CH2O. Within this piece of research, the adhesion attributes of the pristine graphdiyne (PGRD) and Pt-doped GRD (Pt@GRD) for CH2O were examined through DFT calculations. Moreover, the HOMO-LUMO energy levels, electrostatic potentials, energy band structures, adhesion structure parameters, and doping site optimizations of the Pt@GRD were investigated. Based on the results, doping the Pt atom the optimal site (CII) dramatically reduced the energy gap and substantially enhanced the electrical conductance. The PGRD was not suitable for the detection of CH2O with high sensitivity since it used mainly physisorption. However, there was a robust chemical adsorption between Pt@GRD and CH2O via the chemical reaction and hybridization of the Pt-d orbital with the molecular orbital of CH2O. The performance of Pt@GRD as a novel 2D material in detecting CH2O was extremely high. The current results can provide useful insights into developing future sensors for the detection of various gasses.