Bridge effect on the charge transfer and optoelectronic properties of triphenylamine-based organic dye sensitized solar cells: theoretical approach

Selective Capturing of the CO2 Emissions Utilizing Ecological (3-Mercaptopropyl)trimethoxysilane-Coated Porous Organic Polymers in Composite Materials

Capturing carbon dioxide (CO2) is still a major obstacle in the fight against climate change and the reduction of greenhouse gas emissions. To address this problem, we employed a simple Friedel-Crafts alkylation to investigate the effectiveness of porous organic polymers (POPs) based on triphenylamine (TPA) and trihydroxy aryl terms derived from chloranil (CH), designated as TPA-CH POP. We then treated the TPA-CH POP with (3-mercaptopropyl)trimethoxysilane (3-MPTS), forming a TPA-CH POP-SH nanocomposite to enhance CO2 capture. Utilizing FTIR, solid-state NMR, SEM, TEM, along with XPS techniques, the molecular makeup, morphological characteristics, as well as physical features of TPA-CH POP and the TPA-CH POP-SH nanocomposite were thoroughly explored. Upon scorching to 800 °C, the TPA-CH POP-SH nanocomposite demonstrated more thermal durability over TPA-CH POP, achieving a char yield of up to 71.5 wt.%. The TPA-CH POP-SH nanocomposite displayed a 2.5-times better CO2 capture, as well as a comparable adsorption capacity of 48.07 cm3 g-1 at 273 K. Additionally, we found that the TPA-CH POP-SH nanocomposite exhibited an improved CO2/nitrogen (N2) selectivity versus the original TPA-CH POP. Typical enthalpy changes for CO2 capture were somewhat increased by the 3-MPTS coating, indicating greater binding energies between CO2 molecules and the adsorbent surface. Our outcomes demonstrate that a TPA-CH POP composite coated with MPTS is a viable candidate for effective CO2 capture uses. Our findings encourage the investigation of different functional groups and optimization strategies.

Theoretical investigation of substitution effect on the sixth and seventh positions of coumarin derivatives

The linear and non-linear optical properties of 6-donor and 7-donor substituted coumarins were compared using density functional theory (DFT) and time-dependent-DFT (TD-DFT). Charge transfer characteristics were investigated through natural bond order analysis, frontier molecular orbital, and molecular electrostatic potential plots. TD-DFT results suggested that the 6-donor substituted coumarins (PS1, PS3, and PS5) showed red-shifted absorption than the 7-donor substituted coumarins (PS2, PS4, and PS6). The chemical potential (μ) and electrophilicity index (ω) showed direct relation with the band gap and an inverse relation with chemical hardness (η) and hyperhardness (Γ). The global reactivity descriptors μ and ω showed direct and η and Γ showed an inverse correlation with first-order hyperpolarizability (β0) and second-order hyperpolarizability (γ). The β0 and γ for 7-donor substituted coumarin are higher than for 6-donor substituted coumarin.

Theoretical analysis on D-π-A triphenylamine-based dyes for dye-sensitized solar cells: effect of π-bridges on the optoelectronic, and photovoltaic properties

CONTEXT

The dye-sensitized solar cell is a technology unique in its light conversion properties as it operates with record efficiencies in diffused light conditions. The choice of the appropriate sensitizer is one of the important strategies to improve photovoltaic performance of DSSC devices. This theoretical study mainly aims to determine the impact of the π-spacer on the geometric and optoelectronic parameters of sensitizer dyes. For that, we have chosen six organic dyes of Donor-π-Acceptor structure based on triphenylamine unit as electron donor, cyanoacrylic acid as electron acceptor with various π-bridges. The results indicated that the doping process modify dihedral angles and electronic properties by enhancing the planarity and decreasing the gap energy. We have examined the optoelectronic and photovoltaic properties of studied triphenylamine based-dyes. Introducing thiophene and furan as π-spacer groups in D6 dye can effectively decrease the gap energy (E_gap = 2.21 eV), broaden the absorption range (λ_max = 671.19 nm), and promote the light-harvesting properties. The D2 dye based on two pyrrole units presents an improved electron injection driving force (ΔG^inject = - 2.269 eV) and regeneration driving force corresponding to better charge separation. The π-bridge groups can efficiently tune the optoelectronic and photovoltaic properties of sensitizers, which contribute to the efficiency of solar cells.

METHODS

The geometrical and electronic properties of all systems were studied by the DFT method using the correlation exchange functional B3LYP combined with 6-31G(d, p) basis set. On the other hand, the maximum absorption wavelengths λ_max and the corresponding oscillator strengths were calculated using the hybrid functional BHandHLYP and 6-31+G(d) basis set. The solvent tetrahydrofuran (THF) are used to study the effect of the solvent, using the "Conductor-Polarizable Continuum" (C-PCM) model. All calculations were performed using Gaussian 09 program.

A Novel Indole Derivative with Superior Photophysical Performance for Fluorescent Probe, pH-Sensing, and Logic Gates

An indole-related molecules have been considered as the potential fluorescent probes for biological and electrochemical sensing. However, most of the indole probes have been usually used in a single detection mode. Indolium probes that enable accurate detection in complex environments are rarely reported. Here, four novel indole derivatives including the phenyl group substituted with different functional moieties were designed on the basis of the donor-π-acceptor (D-π-A) concept. These derivatives exhibit positive solvatochromism owing to their varied molecular conformations upon contacting to various solvents and the different HOMO-LUMO gaps caused by the difference in electronic push-pull capability of the substituents. Their solid-state fluorescence emissions and multiple chromisms are observed due to the inherent twisted geometries and aggregation modes. In addition, these derivatives show dramatic color and fluorescence responses due to the protonation of the nitrogen and oxygen containing groups, and thus novel colorimetric pH sensors, fluorescent papers and logic gates have been designed.

Push-Pull Effect of Terpyridine Substituted by Triphenylamine Motive—Impact of Viscosity, Polarity and Protonation on Molecular Optical Properties

The introduction of an electron-donating triphenylamine motive into a 2,2′,6′,2′′-terpyridine (terpy) moiety, a cornerstone molecular unit in coordination chemistry, opens new ways for a rational design of photophysical properties of organic and inorganic compounds. A push-pull compound, 4′-(4-(di(4-tert-butylphenyl)amine)phenyl)-2,2′,6′,2′′-terpyridine (tBuTPAterpy), was thoroughly investigated with the use of steady-state and time-resolved spectroscopies and Density Functional Theory (DFT) calculations. Our results demonstrate that solvent parameters have an enormous influence on the optical properties of this molecule, acting as knobs for external control of its photophysics. The Intramolecular Charge Transfer (ICT) process introduces a remarkable solvent polarity effect on the emission spectra without affecting the lowest absorption band, as confirmed by DFT simulations, including solvation effects. The calculations ascribe the lowest absorption transitions to two singlet ICT excited states, S₁ and S₂, with S₁ having several orders of magnitude higher oscillator strength than the “dark” S₂ state. Temperature and viscosity investigations suggest the existence of two emitting excited states with different structural conformations. The phosphorescence emission band observed at 77 K is assigned to a localized ³terpy state. Finally, protonation studies show that tBuTPAterpy undergoes a reversible process, making it a promising probe of the pH level in the context of acidity determination.

Virtual screening of PEBP1 inhibitors by combining 2D/3D-QSAR analysis, hologram QSAR, homology modeling, molecular docking analysis, and molecular dynamic simulations

Human phosphatidylethanolamine binding protein 1 (hPEBP1) is a novel target affecting many cellular signaling pathways involved in the formation of metastases. It can be used in the treatment of many cases of cancer. For these reasons, pharmaceutical companies use computational approaches, including multi-QSAR (2D, 3D, and hologram QSAR) analysis, homology modeling, molecular docking analysis, and molecular dynamic simulations, to speed up the drug discovery process. In this paper, QSAR modeling was conducted using two quantum chemistry optimization methods (AM1 and DFT levels). As per PLS results, we found that the DFT/B3LYP method presents high predictability according to 2D-QSAR, CoMFA, CoMSIA, and hologram QSAR studies, with Q² of 0.81, 0.67, 0.79, and 0.67, and external power with R²_pred of 0.78, 0.58, 0.66, and 0.56, respectively. This result has been validated by CoMFA/CoMSIA graphics, which suggests that electrostatic fields combined with hydrogen bond donor/acceptor fields are beneficial to the antiproliferative activity. While the hologram QSAR models show the contributions of each fragment in improving the activity. The results from QSAR analyses revealed that ursolic acids with heterocyclic rings could improve the activities. Ramachandran plot validated the modeled PEBP1 protein. Molecular docking and MD simulations revealed that the hydrophobic and hydrogen bond interactions are dominant in the PEBP1's pocket. These results were used to predict in silico structures of three new compounds with potential anticancer activity. Similar molecular docking stability studies and molecular dynamics simulations were conducted.

Computational study of the effect of π-spacers on the optoelectronic properties of carbazole-based organic dyes

In this article, we studied a series of dye-sensitized solar cells (DSSCs) type Donor-π-Acceptor involving carbazole as donors and cyanoacrylic acid as acceptors of the electrons. These cells are linked by different π-spacer unit's, with the aim to develop new organic dyes with high-performance optoelectronic properties. Different units have been introduced in the π-bridge in order to investigate their effects on the structural and optoelectronic properties of the studied compounds, as well as their adsorbed compounds-titanium dioxide (TiO₂) semi-conductor. We evaluated and assessed the important relevant parameters that influence the performance of photovoltaic cell to measure their involvement in the short-circuit photocurrent density (J_sc). Using Density Functional Theory (DFT) and Time-Dependent-BHandHLYP, the geometrical and optoelectronics properties have been predicted theoretically. The results obtained indicate that introducing the oxazole (S5) and thiazole (S6) molecules in the π-spacer have significant impact on the geometric properties for D5-D6 dyes. This results in the fact that dye D5 has a planar structure. Also, the insertion of the thiophene, oxazole and thiazole units improves the energies of the HOMO and LUMO molecular orbitals of D1, D5, and D6 dyes. Moreover, these results show the ability of electron transfer and regeneration from the studied sensitizers (D1-D6). Also, it can be noted that the application of the pyrrole group in the π-spacer moiety of the dye (D2) improves the electron's transfer performance with a lower regeneration motive force ΔG^reg, a more negative injection driving forces (ΔG^inject), and a higher values of open circuit-voltage (Voc).

Synthesis, spectral characterizations, molecular geometries and electronic properties of phenothiazine based organic dyes for dye-sensitized solar cells

A number of organic dye compounds is developed and used as dye-sensitized solar cells in order to produce cost-effective devices and enhance cell performance. In this aspect, phenothiazine based organic dye compounds such as (E)-3-(7-bromo-10-phenyl-10H-phenothiazine-3-yl) acrylic acid and (E)-3-(7-bromo-10-phenyl-10H-phenothiazine-3-yl)-2-cyanoacrylic acid have been synthesized. The synthesized dye compounds have been characterized through Fourier-transform infrared, Fourier-transform Raman and nuclear magnetic resonance spectroscopic method. The Ultraviolet–Visible spectra were recorded and electronic features were discussed with the theoretically calculated bands using time-dependent density functional theory. Frontier molecular orbital, natural bond orbital and non-linear optical properties have been calculated for these compounds using density functional theory. The photosensitization properties such as light harvesting efficiency and electron injection driving force (∆G inject) have also been discussed.