Synthesis and Characterization of 2D-D-π-A-Type Organic Dyes Bearing Bis(3,6-di-tert-butylcarbazol-9-ylphenyl)aniline as Donor Moiety for Dye-Sensitized Solar Cells

Promising Molecular Architectures for Two-Photon Probes in the Diagnosis of α-Synuclein Aggregates

The abnormal deposition of protein in the brain is the central factor in neurodegenerative disorders (NDs). These detrimental aggregates, stemming from the misfolding and subsequent irregular aggregation of α-synuclein protein, are primarily accountable for conditions such as Parkinson's disease, Alzheimer's disease, and dementia. Two-photon-excited (TPE) probes are a promising tool for the early-stage diagnosis of these pathologies as they provide accurate spatial resolution, minimal intrusion, and the ability for prolonged observation. To identify compounds with the potential to function as diagnostic probes using two-photon techniques, we explore three distinct categories of compounds: Hydroxyl azobenzene (AZO-OH); Dicyano-vinyl bithiophene (DCVBT); and Tetra-amino phthalocyanine (PcZnNH2). The molecules were structurally and optically characterized using a multi-technique approach via UV-vis absorption, Raman spectroscopy, three-dimensional fluorescence mapping (PLE), time-resolved photoluminescence (TRPL), and pump and probe measurements. Furthermore, quantum chemical and molecular docking calculations were performed to provide insights into the photophysical properties of the compounds as well as to assess their affinity with the α-synuclein protein. This innovative approach seeks to enhance the accuracy of in vivo probing, contributing to early Parkinson's disease (PD) detection and ultimately allowing for targeted intervention strategies.

Exploring Structure-Property Relationships in a Bio-Inspired Family of Bipodal and Electronically-Coupled Bistriphenylamine Dyes for Dye-Sensitized Solar Cell Applications

A bio-inspired family of organic dyes with bichromic-bipodal architectures were synthesized and tested in dye-sensitized solar cells (DSSC). These dyes are comprised of a D-π-D-A motif with two triphenylamine (TPA) units acting as donors (D) and two cyanoacetic acid acceptors (A) capable of binding to a titania semiconductor. The role of the thiophene π-spacer bridging the two TPA units was examined and the distal TPA (relative to TiO2) was modified with various substituents (-H, -OMe, -SMe, -OHex, -3-thienyl) and contrasted against benchmark L1. It was found that the two TPA donor units could be tuned independently, where π-spacers can tune the proximal TPA and R-substituents can tune the distal TPA. The highest performing DSSCs were those with -SMe, 3-thienyl, and -H substituents, and those with one spacer or no spacers. The donating abilities of R-substituents was important, but their interactions with the electrolyte was more significant in producing high performing DSSCs. The introduction of one π-spacer provided favourable electronic communication within the dye, but more than one was not advantageous.

Theoretical insight on hybrid nanocomposites of graphene quantum dot and carbazole-carbazole dyes as an efficient sensitizer of DSSC

The feasibility of the hybrid nanocomposites of the graphene quantum dot (GQD) and carbazole-carbazole dyes as the efficient sensitizer of dye-sensitized solar cells (DSSC) is investigated. By using the first principles density functional theory (DFT), we fully optimize the geometrical structures of GQD, the carbazole-carbazole dyes, and their hybrid nanocomposites. The harmonic frequency analysis is used to confirm the energy stability of the optimized structures. The optical absorptions of the structures are calculated with the time-dependent DFT (TDDFT). Using the I^-/I₃^- electrolyte and the conduction band minimum of TiO₂ electrode as a sample, we examine the feasibility of the nanocomposites as the sensitizer of DSSC with the charge spatial separation and the molecular orbital energy levels of the nanocomposites. The results demonstrate all the considered nanocomposites have suitable energy levels of the frontier orbitals and significantly charge spatial separation. TDDFT results show the oscillator strengths of all nanocomposites demonstrate the obvious enhancement in the visible light region. Moreover, the appropriate open-circuit voltage value, the larger light-harvesting efficiency, and larger driving force are also identified for these nanocomposites. Therefore, the nanocomposites could be the more promising candidates of sensitizer for DSSC in comparison with the separate carbazole-carbazole dyes.

Efficient and straightforward click synthesis of structurally related dendritic triazoles

Structurally related triazolic dendrimers were efficiently synthesized applying CuAAC reaction.

New D–D–π–A type organic dyes having carbazol-N-yl phenothiazine moiety as a donor (D–D) unit for efficient dye-sensitized solar cells: experimental and theoretical studies

DSSCs using novel organic dyes (CPhTnPA, n = 0–2) with carbazol-N-yl phenothiazine moiety as a donor (D–D) unit as the sensitizers exhibited efficiency as high as 7.78% which reached 95% with respect to that of the reference N719-based device (8.20%).

BODIPY based hyperbranched conjugated polymers for detecting organic vapors

BODIPY-based hyperbranched polymer showed improved selectivity and sensitivity for toluene as originated from the strong π–π interaction and high porosity within polymer matrix.

Porphyrin Sensitizers Bearing a Pyridine-Type Anchoring Group for Dye-Sensitized Solar Cells

Three novel efficient donor-acceptor porphyrins, MH1-MH3, with a pyridine-type acceptor and anchoring group were synthesized and their optical, electrochemical, and photovoltaic properties investigated. Replacing the commonly used 4-carboxyphenyl anchoring group with 2-carboxypyridine, 2-pyridone, and pyridine did not significantly change the absorption and electrochemical properties of the porphyrin dyes. These new porphyrin dyes MH show power conversion efficiencies of 8.3%, 8.5%, and 8.2%, which are comparable to that of the benchmark YD2-o-C8 (η=8.25%) under similar conditions. It was demonstrated that 2-carboxypyridine is an efficient and stable anchoring group as MH1 and showed better cell performance and long-term stability than YD2-o-C8 under light soaking conditions.

Synthesis and characterization of new triphenylamino-1,8-naphthalimides for organic light-emitting diode applications

Three new triphenylamine derivatives with various numbers of N-phenyl-1,8-naphthalimide pendants were synthesized and fabricated into OLED devices.

Functional tuning of organic dyes containing 2,7-carbazole and other electron-rich segments in the conjugation pathway

Organic dyes containing a triarylamine donor, a cyanoacrylic acid acceptor and a conjugation pathway composed of 2,7-carbazole, thiophene and fluorene have been synthesized and characterized as sensitizers for TiO₂-based dye-sensitized solar cells.

Theoretical study on molecular design and optical properties of organic sensitizers

A series of organic sensitizers based on different configurations such as D-π-A, D-[π]n-A, D-π-[A]n, [D]n-π-A, D-π-A-π-D, D-π-[A]n-π-D and D-[π-A]n-π-D (where n = 1-4) are designed using theoretical methods. The effects of repeating π-linker, donor-acceptor moieties and the substitution of additional donor-acceptor moieties on the optoelectronic properties have been addressed. Our results show that the strength of the acceptor units changes the mono band absorption into dual band absorption in all the considered strategies. We found that repeating π-linker/donor moieties in the D-π-A series enhances the intensity of the absorption and can tune their absorption spectra from UV-to-visible and visible to near IR regions by repeating acceptor units. Also, the present results indicate that the D-π-A-π-D configuration shows improved optical properties than the conventional D-π-A structure. This theoretical study explores the new configurations and design strategies of organic dyes for developing efficient light harvesting devices working in the whole visible and near IR regions.

Carbazole-dendrimer-based donor-π-acceptor type organic dyes for dye-sensitized solar cells: effect of the size of the carbazole dendritic donor

A series of novel D-π-A type organic dyes, namely, GnTA (n = 1-4), containing carbazole dendrons up to fourth generation as a donor, bithiophene as π-linkage, and cyanoacrylic acid as acceptor were synthesized and characterized for applications in dye-sensitized solar cells (DSSCs). The photophysical, thermal, electrochemical, and photovoltaic properties of the new dyes as dye sensitizers were investigated, and the effects of the carbazole dendritic donors on these properties were evaluated. Results demonstrated that increasing the size or generation of the carbazole dendritic donor of the dye molecules enhances their total light absorption abilities and unluckily reduces the amount of dye uptake per unit TiO2 area because of their high molecular volumes. The latter was found to have a strong effect on the power conversion efficiency of DSSCs. Importantly, electrochemical impedance spectroscopy (EIS) revealed that the size or generation of the donor had a significant influence on a charge-transfer resistance for electron recombination at the TiO2/electrolyte interface, causing a difference in open circuit voltage (Voc) of the solar cells. Among them, dye G1TA containing first generation dendron as a donor (having lowest molecular volume) exhibited the highest power conversion efficiency of 5.16% (Jsc = 9.89 mA cm(-2), Voc = 0.72 V, ff = 0.73) under simulated AM 1.5 irradiation (100 mW cm(-2)).

Dithieno[2,3-d;2′,3′-d′]benzo[1,2-b;4,5-b′]dithiophene based organic sensitizers for dye-sensitized solar cells

We report two novel D–π–A type organic dyes with a coplanar dithieno[2,3-d;2′,3′-d′]benzo[1,2-b;4,5-b′]dithiophene (DTBDT) as π-spacer for dye-sensitized solar cells.