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The new design of 6,6′-di(thiophen-2-yl)-4,4′-bipyrimidine (DTB)-based organic dyes (TCIT1-TCIT6) for dye-sensitized solar cell (DSSC) application was systematically designed by a donor (D), π-linker, and acceptor (A) design to form the D-π-D-π-A structure. The exchange–correlation (XC) as well as long-range corrected (LC) functionals were utilized to represent these dyes in density functional theory (DFT) and time-dependent DFT (TD-DFT) techniques. The TD-CAM-B3LYP approach was perfectly matched the DTB dye. Energy gaps between highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) ranged between 1.73-2.92 eV. Their light-harvesting efficiency (LHE) values ranged between 0.001-0.106 eV with dye TCIT5 with the highest value. The open circuit voltage calculated against the DTB as donor moiety ranged 2.45–3.64 eV with positive values to demonstrate their ON position in their solar devices. All the dyes showed a very short excited-state lifetime ranging between 0.0001-0.0051 ns which showed how easily they can shift from an excited- (fluorescent) to ground-state position. Improved results for DSSCs were provided by the intended dyes in addition to their high horizontal dipole moment (µnormal) and open circuit photovoltage (eVOC). It benefits increased efficiency as a result. The findings of the current theoretical analysis show that all D-π-D-π-A dyes may be suitable sensitizers for DSSC applicability. [ABSTRACT FROM AUTHOR]

Context: In this study, new visible light harvesting dyes (MBR1–MBR5) have been designed as efficient materials with silyl based anchoring abilities on semiconducting units for future dye-solar cells applications. Their unique molecular structures of novel D-π-ASemiconductor type were evaluated thoroughly by density functional theory (DFT) calculations. To enhance the optical performance in visible region, a novel dye structure (MBR) was derived from the chemical structure of mordant black (MB) dye with electron acceptor semiconducting units (MBR1–MBR5). Methods: The Coulomb-attenuating Becke, 3-parameter, Lee–Yang–Parr (CAM-B3LYP) functional, which had a hybrid and long-range correlation with 6-31G + (d,p), generated a λ max (683 nm) that was very comparable to its experimental value (672 nm). The energies of highest occupied molecular orbitals (HOMO), lowest unoccupied molecular orbitals (LUMO), and their HOMO–LUMO energy gaps (HLG) were calculated. Their ionization potentials (IP) varied from 5.616 to 8.320 eV, demonstrating their good electron donating trend. The λ max values of dyes displayed a significant red shift from MBR (682 nm) value with range 565–807 nm except MBR1 which was slightly blue shifted. The dye MBR4, which had the smallest HLG (0.23 eV) had the greatest second order nonlinear optical (NLO) response of 144,234 Debye-Angstrom−1. The DFT calculated results provided insight into the creation of new silyl anchoring groups for future DSSCs material designs with increased stability and effectiveness. The goal of the current study is to forecast the development of novel NLO materials with a D-π-ASemiconductor design that use semiconductors as anchoring groups to adhere to a surface. [ABSTRACT FROM AUTHOR]

An electrochemical sensor based on an antimony/nitrogen-doped porous carbon (Sb/NPC) composite has been developed for the quantitative detection of albumin from hepatocellular carcinoma (HCC) patients. Sb/NPC is hydrothermally synthesized from Sn/NPC precursors. The synthesized precursor (Sn/NPC) and the product (Sb/NPC) are characterized by XRD, FTIR, TGA, UV/Vis, SEM, and AFM. Cyclic voltammetry, chronoamperometry, and electrochemical impedance studies are used to investigate the electrochemical performance of Sb/NPC-GCE. Sb/NPC-GCE detects albumin at physiological pH of 7.4 in the potential range 0.92 V and 0.09 V for oxidation and reduction, respectively. LOD and recovery of Sb/NPC-GCE for the determination of albumin are 0.13 ng.mL−1 and 66.6 ± 0.97–100 ± 2.73%, respectively. Chronoamperometry of the modified working electrode demonstrates its stability for 14 h, indicating its reusability and reproducibility. Sb/NPC-GCE is a selective sensor for albumin detection in the presence of interfering species. The electrode has been applied for albumin detection in human serum samples of HCC patients. A negative correlation of albumin with alpha-fetoprotein levels in HCC patients is observed by statistical analysis. [ABSTRACT FROM AUTHOR]