Advancements in Carbazole-Based Sensitizers and Hole-Transport Materials for Enhanced Photovoltaic Performance
Carbazole-based molecules play a significant role in dye-sensitized solar cells (DSSCs) due to their advantageous properties. Carbazole derivatives are known for their thermal stability, high hole-transport capability, electron-rich (p-type) characteristics, elevated photoconductivity, excellent chemical stability, and commercial availability. This review focuses on DSSCs, including their structures, working principles, device characterization, and the photovoltaic performance of carbazole-based derivatives. Specifically, it covers compounds such as 2,7-carbazole and indolo[3,2-b]carbazole, which are combined with various acceptors like benzothiadiazole, thiazolothiazole, diketopyrrolopyrrole, and quinoxaline, as reported over the past decade. The review will also outline the relationship between molecular structure and power-conversion efficiencies. Its goal is to summarize recent research and advancements in carbazole-based dyes featuring a D-π-A architecture for DSSCs. Additionally, this review addresses the evolution of carbazole-based hole-transport materials (HTMs), which present a promising alternative to the costly spiro-OMeTAD. We explore the development of novel HTMs that leverage the unique properties of carbazole derivatives to enhance charge transport, stability, and overall device performance. By examining recent innovations and emerging trends in carbazole-based HTMs, we provide insights into their potential to reduce costs and improve the efficiency of DSSCs.
Effect of substituents in governing the homolytic gas-phase P–H bond dissociation enthalpies of phosphine-type oxides (R1R2P(=O)H)
This study reports the gas-phase homolytic P–H BDEs of a set of 30 phosphine-type oxides (i.e., R1R2P(=O)H) obtained using the W1w thermochemical protocol. We note that the P–H BDEs (at 298 K) of the species in this dataset differ by as much as 157.2 kJ mol–1, with (H2B)2P(=O)H having the lowest BDE (249.3 kJ mol–1) and F2P(=O)H having the highest (406.5 kJ mol–1). Furthermore, using the full set of 30 all-electron, non-relativistic, vibrationless bottom-of-the-well W1w P–H BDEs as reference values, we have identified several well-performing DFT methods that could be applied to the computation of the P–H BDEs of phosphine-type oxides. The best-performing DFTs (in conjunction with the A'VTZ basis set) were shown to be MN12-SX (MAD = 1.7 kJ mol–1) and MN12-L (MAD = 2.7 kJ mol–1).
Tailoring the Optoelectronic Properties of Soybean-Derived Nitrogen Self-Doped Carbon Dots through Composite Formation with KCl and Zeolite, Synthesized Using Autogenic Atmosphere Pyrolysis
This article investigates the environmentally friendly synthesis and characterization of carbon dots (CDs) derived from soybean biomass, in conjunction with their composites containing potassium chloride (KCl) or zeolite. By using an environmentally sustainable synthetic approach, this study sought to unlock the potential of these materials for various applications. The physicochemical properties of the CDs and composites were comprehensively analyzed using various techniques including scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analysis. In addition, various optical properties such as UV–Vis absorption, band gap, and excitation–emission behavior were investigated. A key finding to arise from this study was that the inclusion of a doping agent such as KCl or zeolite significantly reduced the size of the resulting CDs. In this light, whereas the undoped species are associated with average sizes of 8.86 ± 0.10 nm, those doped with either zeolite or KCl were associated with average sizes of 3.09 ± 0.05 and 2.07 ± 0.05 nm, respectively. In addition, it was shown that doping with either zeolite or KCl resulted in an alteration of the elemental composition of the CDs and influenced their optical properties, especially their excitation-dependent emission. These promising results point to potential applications in environmental sensing and energy-related fields.
A quantum chemical study of the effect of substituents in governing the strength of the S–F bonds of sulfenyl-type fluorides toward homolytic dissociation and fluorine atom transfer
The gas-phase homolytic S–F bond dissociation energies (BDEs) of 21 sulfenyl-type fluorides (RSF) have been obtained using the W1w thermochemical protocol. The BDEs (at 298K) for the species in this set range from 316.2 (HCCSF) to 368.1 (H2CCHSF) kJ mol–1. We additionally report fluorine-transfer energies (FTEs), corresponding to the energetics of fluorine transfer from RSF to H2S. At 298K, the FTEs range from –10.7 (H2AlSF) to 90.7 (MeHNSF) kJ mol–1. We have also assessed the performance of a wide range of density functional theory (DFT) and double-hybrid DFT methods (in conjunction with the A'VQZ basis set) for the calculation of these quantities. For the calculation of S–F BDEs, the M06-2X procedure offers the best performance, with a mean absolute deviation (MAD) of 1.6kJ mol–1, whilst for the FTEs, B2K-PLYP and DSD-PBEP86 offer the best performance with MADs of 0.5kJ mol–1.
Trade-Off between Degradation Efficiency and Recyclability: Zeolite-Enhanced Ni3−xCoxS4 Catalyst for Photocatalytic Degradation of Methylene Blue
We herein report successful syntheses of both nickel cobalt sulfide (NCS) and its composite with zeolite (NCS@Z) using a solvothermal method. Techniques such as EDX analysis, SEM, and molar ratio determination were used for product characterization. The incorporation of NCS significantly changed the surface roughness and active sites of the zeolite, improving the efficiency of methylene blue degradation and its reusability, especially under UV irradiation. In comparing the pseudo-first order rates, the highest degradation efficiency of methylene blue was achieved with NCS-2@Z, having a degradation extent of 91.07% under UV irradiation. This environmentally friendly approach offers a promising solution for the remediation of methylene blue contamination in various industries.