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Theoretical Study of a Class of Organic Da????a??A Dyes for Polymer Solar Cells: Influence of Various ??a??Spacers
摘要： A class of D‐π‐A compounds that can be used as dyes for applications in polymer solar cells has theoretically been designed and studied, on the basis of the dyes recently shown by experiment to have the highest power conversion efficiency (PCE), namely the poly[4,8‐bis(5‐(2‐(PBDTS‐TZNT) butylhexylthio)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b’]dithiophene‐2,6‐diyl‐alt‐TZNT] and poly[4,8‐bis(4‐fluoro‐5‐(2‐butylhexylthio)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b’]dithiophene‐2,6‐ diyl‐alt‐TZNT] (PBDTSF‐TZNT) substances. Electronic structure theory computations were carried out with density functional theory and time‐dependent density functional theory methods in conjunction with the 6?311G (d, p) basis set. The PBDTS donor and the TZNT (naphtho[1,2‐c:5,6‐c]bis(2‐octyl‐[1,2,3]triazole) acceptor components were established from the original substances upon replacement of long alkyl groups within the thiophene and azole rings with methyl groups. In particular, the effects of several π‐spacers were investigated. The calculated results confirmed that dithieno[3,2‐b:2′,3′‐d] silole (DTS) acts as an excellent π‐linker, even better than the thiophene bridge in the original substances in terms of well‐known criteria. Indeed, a PBDTS‐DTS‐TZNT combination forms a D‐π‐A substance that has a flatter structure, more rigidity in going from the neutral to the cationic form, and a better conjugation than the original compounds. The highest occupied molecular orbital (HOMO)‐lowest unoccupied molecular orbital (LUMO) energy gap of such a D‐π‐A substance becomes smaller and its absorption spectrum is more intense and red‐shifted, which enhances the intramolecular charge transfer and makes it a promising candidate to attain higher PCEs.
关键词： DFT calculations,PCEs,DTS,PBDTS‐TZNT and PBDTSF‐TZNT,D‐π‐A dyes,polymer solar cells
更新于2025-09-23 15:19:57
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Efficient Solar Cells based on Concerted Companion Dyes Containing Two Complementary Components: An Alternative Approach for Cosensitization
摘要： With the purpose to achieve panchromatic absorption for constructing efficient dye-sensitized solar cells (DSSCs), the cosensitization approach of using two dyes with complementary absorption has been developed with great success. However, this approach usually requires time-consuming optimization of a number of parameters for controlling the ratio and distribution of the two coadsorbed dyes on TiO2 film, which limits the potentials of this strategy. We herein report an alternative approach for developing efficient DSSCs by designing a class of “concerted companion dyes” with two complementary dye components linked covalently. Thus, a newly synthesized organic dye Z2 was linked to a recently reported doubly strapped porphyrin dye XW51 through flexible chains with various lengths to afford XW60?XW63. These dyes exhibit excellent absorption and efficiencies in the range of 8.8%-11.7%. Notably, upon coadsorption with chenodeoxycholic acid (CDCA), XW61 affords an impressive efficiency of 12.4%, a record for iodine electrolyte-based DSSCs, to the best of our knowledge. In addition, these dyes also exhibit the advantages of easy cell fabrication, simple optimization, as well as excellent photostability.
关键词： dye-sensitized solar cells,photovoltaic performance,concerted companion dyes,cosensitization,panchromatic absorption
更新于2025-09-23 15:19:57
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Timea??dependent density functional theory investigations on structural modification in carbazolea??based organic photosensitizers to improve electron injection in dyea??sensitized solar cell
摘要： The time-dependent density functional theory approach, implemented at hybrid-B3LYP, GGA-PBE, and density functional-based tight binding levels of theory, was used to model photoinjection in organic dye/TiO2 quantum dot to explore the prospects of improvement of dye-sensitized solar cell (DSSC). The photosensitizer used in this study consisted of six carbazole-based organic dyes, a cyanoacrylic acid group as an acceptor and an oligothiophene π-bridge spacer. The modifications were made in the dyes by increasing the length of the spacer by adding thiophene and oxadiazole rings at different positions of the donor-acceptor bridge. The structural variations appeared to alter the electronic and optical properties of dyes studied via energy levels and excitation spectra. The UV-Vis spectra calculated for all the dyes in solvents exhibited a red shift in spectral peaks with an increase in the polarity of the solvents. The findings of the study pointed toward the indirect photoinjection of the dye-(TiO2)96 complex for six different dyes. The substitution of the oxadiazole ring at the center and addition of a thiophene ring at the edge of the spacer produced two dyes that exhibited the lowest injection energies of 0.11 and 0.17 eV, along with the regeneration energies of 1.18 and 1.12 eV, respectively. The dyes reported here may have promising applications in photoanode for enhancing the performance of DSSC.
关键词： DSSC,photoinjection,density functional theory,organic dyes
更新于2025-09-23 15:19:57
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NIR organic dyes based on phenazine-cyanine for photoacoustic imaging-guided photothermal therapy
摘要： As non-invasive diagnosis and therapy methods, photoacoustic (PA) imaging and photothermal therapy (PTT) have attracted extensive attention. Herein, two new acceptor–donor–acceptor near-infrared organic phenazine-cyanine dyes PH-1 and PH-2 were reported for photoacoustic imaging-guided photodynamic therapy. In the strong donor phenazine molecule, the electron-withdrawing indole salt unit was introduced for absorption to the near-infrared region. To improve water solubility, the two organic dyes were assembled with human serum albumin (HSA) to form nanoparticles of appropriate sizes, i.e., PH-1@HSA and PH-2@HSA, which showed excellent stability in both weakly acidic and weakly basic environments. Moreover, the results showed that PH-1@HSA and PH-2@HSA nanoparticles can effectively transform luminous energy to thermal energy in vitro and in vivo, and they can be utilized for PA imaging. Importantly, PH-1@HSA can accumulate in mice subcutaneous tumors by enhanced permeability and retention (EPR) and damage cancer tissues effectively.
关键词： NIR organic dyes,phenazine-cyanine,nanoparticles,photoacoustic imaging,photothermal therapy
更新于2025-09-19 17:15:36
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A physicochemical study of ophthalmological vital dyes: From dimerization equilibrium in buffer solution to their liposomal dispersions
摘要： Vital dyes are used both in intra-operative and diagnostic ophthalmology as liquid solutions wherein dyes self-associate reducing their effects. Hence, an efficient dyes-delivery system is required to carry the maximum fraction of dye administered to the target site. In this study primarily two aspects of indocyanine green, patent blue V and brilliant blue G have been investigated. First, band profiles of UV–Vis absorption and emission spectra, acquired as a function of dye concentration in buffer solutions(pH = 7.4), have been analyzed to calculate the dimerization constant. Results demonstrate that their self-assembly properties have to be correlated to the molecular polarization. Second, the vital dyes have been loaded into liposomes prepared with the thin-film hydration method followed by extrusion. Encapsulation efficiency has been calculated to be 30%. Scanning electron microscopy and dynamic light scattering measurements have revealed that dye inclusion reduces the liposome diameter. Activation energy of liposome diffusion has been extracted by Arrhenius plots. Zeta potential measurements as a temperature function have been exploited to evaluate a dimensionless surface charge and prove that ratio charge(dye-loaded liposome)-to-charge(blank liposome) is always greater than unity and decreases with temperature.
关键词： Liposomes,Fluorescence,Vital dyes,UV–Visible,ζ-potential
更新于2025-09-19 17:15:36
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C,N-doped TiO2 monoliths with hierarchical macro-/mesoporosity for water treatment under visible light
摘要： C,N-doped TiO2 monoliths with homogeneous interconnected macro-/mesoporous hierarchical porosity, consisting in 83% anatase phase, exhibiting high visible light absorption were prepared in one pot synthesis. The hierarchical porosity was controlled by coupling a sol-gel method with a spinodal decomposition and the improved visible light absorption was obtained by self C,N-grafting during thermal treatment. Titanium isopropoxide, N-methylformamide, poly(ethylene oxide), and hydrochloric acid were used as reagents to form a sol, which was then treated at 40 and 60 °C, followed by a solvothermal treatment in autoclave at 200 °C in isopropanol. The monoliths were further heated at different temperatures from 250 to 500 °C under air. The best compromise between the structural and textural properties (TiO2 phase, surface, volume, pore diameter), the visible light absorbance and the mechanical properties was obtained for a calcination at 350 °C for 5 h. In batch mode, in glass containers, the monoliths demonstrated remarkable efficiency as photocatalysts under natural sunlight and artificial visible light with the total discoloration of the azo dye Orange G aqueous solution in 1 h compared to benchmark TiO2 P25 nanoparticles, which proved inefficient under these conditions. More interestingly, the monoliths used as reactors in flow mode in a recirculating system proved very efficient for the total discoloration of Orange G dye solution revealing the high potential of these TiO2 monoliths for continuous flow wastewater treatment under visible light.
关键词： Visible light,TiO2 monolith,Flow process,Dyes degradation,Wastewater treatment,Photocatalysis
更新于2025-09-19 17:15:36
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Indolo[3,2- <i>b</i> ]indole donor-based D–π–A dyes for DSCs: investigating the role of π-spacers towards recombination
摘要： Dye solar cells (DSCs) are gaining increasing interest since the recent realization of their high-performance in low/indoor light environments. Fused conjugated metal-free organic dyes have become a prominent class of dyes used in DSC in recent times by virtue of their better backbone rigidity, efficient charge transport properties, and the opportunity they provide for further structural modifications. Herein, we report the synthesis and characterization of three metal-free D–π–A organic dyes employing indolo[3,2-b]indole as the donor unit. The optical, electrochemical and photovoltaic properties have been analyzed in detail as a function of π-spacers, namely, benzene (IID-1), thiophene (IID-2) and furan (IID-3). Eventually, the best performance was demonstrated by the dye bearing benzene as the π-spacer. The role of recombination in determining the photovoltaic performance as a function of the nature of π-spacers was explored in detail, using various perturbation techniques on the fabricated devices, and compared with the results obtained from molecular orbital calculations.
关键词： π-spacers,Recombination,2-b]indole,Dye solar cells,Indolo[3,Photovoltaic performance,D–π–A dyes
更新于2025-09-19 17:15:36
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Critical Review—Recent Progress in NIR Fluorophores Emitting over 1000 nm for Bioimaging
摘要： During the last five years, significant advances have been made in the synthesis of near-infrared (NIR) fluorophores emitting over 1000 nm for non-invasive deep-tissue imaging. Nano-materials such as single-walled carbon nanotubes (SWCNTs), following Ag2S and PbS quantum dots (QDs) have been employed as the first-generation NIR fluorescent probes, by which superior capabilities of NIR fluorescence imaging at the wavelengths of 1000–1400 nm (second NIR window) have been demonstrated. Recently, from the viewpoint of biomedical applications, organic-dye based NIR fluorophores emitting beyond 1000 nm have been synthesized. In this short review, we focus on recent advances in nanomaterial and organic-dye based NIR fluorophores for intravital deep bioimaging in the second NIR window.
关键词： bioimaging,organic dyes,second NIR window,nanomaterials,NIR fluorophores
更新于2025-09-19 17:15:36
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The electronic applications of stable diradicaloids: present and future
摘要： Organic molecules with unpaired electrons are intriguing for advanced applications in molecular electronics, spintronics and organic batteries, as well as other possible applications. Among them, diradicaloids have received growing attention due to the characteristic resonance structures between open-shell and closed-shell forms that lead to unique properties such as low energy bandgap and strong intermolecular spin–spin interaction. Therefore, in recent years, vast efforts have been devoted to investigate the synthesis, structure and fundamental properties of diradicaloids. However, the electronic applications of diradicaloids still remain in an early stage. Only a few diradicaloids have already found their place in electronic devices. In this perspective, we summarize the recent development of electronic applications of stable diradicaloids. The challenges and opportunities of stable diradicaloids for future electronic applications are also discussed.
关键词： spintronics,organic electronics,organic batteries,OFETs,NIR dyes,OPDs,diradicaloids,electronic applications
更新于2025-09-19 17:15:36
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Multicolor Flow Cytometry-based Quantification of Mitochondria and Lysosomes in T Cells
摘要： T cells utilize different metabolic programs to match their functional needs during differentiation and proliferation. Mitochondria are crucial cellular components responsible for supplying cell energy; however, excess mitochondria also produce reactive oxygen species (ROS) that could cause cell death. Therefore, the number of mitochondria must constantly be adjusted to fit the needs of the cells. This dynamic regulation is achieved in part through the function of lysosomes that remove surplus/damaged organelles and macromolecules. Hence, cellular mitochondrial and lysosomal contents are key indicators to evaluate the metabolic adjustment of cells. With the development of probes for organelles, well-characterized lysosome or mitochondria-specific dyes have become available in various formats to label cellular lysosomes and mitochondria. Multicolor flow cytometry is a common tool to profile cell phenotypes, and has the capability to be integrated with other assays. Here, we present a detailed protocol of how to combine organelle-specific dyes with surface markers staining to measure the amount of lysosomes and mitochondria in different T cell populations on a flow cytometer.
关键词： lysosome,Flow cytometry,organelle-specific dyes,mitochondria,multicolor,T cell
更新于2025-09-19 17:15:36