Red-shifted Absorption Bands Research Articles

Readily constructed squaraine J-aggregates with an 86.0 % photothermal conversion efficiency for photothermal therapy

The development of photothermal agents with high photothermal conversion efficiency (PCE) and long absorption wavelengths is crucial for safe and effective anti-cancer treatment. However, achieving these advantages often requires precise molecular design and complex synthetic procedures. In this study, we present a simple, precise, and effective method for fabricating photothermal agents with high PCE using long wavelength excitation. This approach involves linking two electron-donating components, diphenylamine (DPA), and an electron-withdrawing squaraine (SQ), via a π-bridge thiophene (T). The resulting D-π-A-π-D structure leads to a red-shifted absorption band. Within the DTS structure, DPA functions as a molecular rotor, T serves as a coplanar backbone, and SQ promotes J aggregation. When DTS nanoparticles (NPs) are fabricated using an amphiphilic nano-carrier, the maximum absorption wavelength shifts from 701 to 803 nm. This shift is accompanied by reduced fluorescence and an exceptionally high PCE of 86.0 %. Both in vitro and in vivo assessments confirm that DTS NPs exhibit strong potential for photothermal antitumor therapy. Overall, this strategy offers a valuable framework for designing photothermal agents with clinical applications in mind, offering a simpler and more efficient approach to achieving high PCE and long absorption wavelengths.

Novel donor-acceptor-donor type electrochromic polymers based on 1,3-indandione modified triphenylamine derivatives as new acceptor units

Two donor (D)-acceptor (A)-donor (D) type of conjugated monomers, ITPA and ICTPA, consisted of 1H-indene-1,3(2H)-dione (IN)- or 2-(3-oxo-2,3-dihydroinden-1-ylidene)-malononitrile (INCN)-substituted triphenylamine as the acceptor unit, were synthesized by Stille coupling reaction and Knovenagel condensation reaction, and their corresponding polymers (PITPA and PICTPA) were prepared by electrochemical polymerization. Both ITPA and ICTPA hade low initial oxidation potential of 0.70 V and 0.76 V, respectively, which was conducive to achieve high-quality polymer films. In comparison with FTPA which was not substituted by IN unit, ITPA and ICTPA exhibited the distinct red-shifted and dual absorption bands due to the stronger electron-withdrawing ability of IN and INIC units. Moreover, the electrochromic results demonstrated that PITPA possessed much higher optical contrast of 41 %, higher coloration efficiency (CE) of 445.5 cm2 C−1 at 1100 nm with extremely fast response time as low as 0.3 s, and a promising optical memory behavior compared with its counterpart without IN unit. These results suggested that the introduction of IN unit into triphenylamine could improve the electrochromic performance of the conjugated polymers and also provide a new strategy to develop novel and high-performance electrocheomic polymers.

Perylene-3,4,9,10-tetracarboxylic dianhydride dye intercalated liquid crystal molecules: Synthesis, spectroscopic characterizations and photoluminescence dynamics

The present research explores the interaction between perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA)-dye (PD) and 3b {(E)-1-[3-fluoro-4-(pentyloxy)phenyl]-2-(4-methylphenyl)diazene} liquid crystal (LC) mesophase, 3c{(E)-1-[3-fluoro-4-(hexyloxy)phenyl]-2-(4-methylphenyl)diazene} nematic liquid crystal (NLC) molecule. Spectroscopic characterizations of 3b@PD LC mesophase and 3c@PD NLC molecule were carried out using scanning electron microscopy (SEM), polarizing optical microscope (POM), Raman, Fourier transform infrared spectroscopy (FT-IR), and UV–visible analytical methods. The UV–visible studies revealed a red shift in absorption bands (348.0 nm to 374 nm) with a decrease in optical band gap from 2.43 eV to 2.25 eV. Room temperature photoluminescence (RTPL) spectra of 3b@PD LC mesophase exhibited blue light emission characteristics centred at 453.1 nm and 3c @PD NLC molecule showed broad emission peaks located at 400.7 nm and 324.8 nm. Steady-state photoluminescence (SSPL) spectra showcased indigo-purple emission bands corresponding to the wavelengths 303–353 nm, 420.5 nm, 418 nm, 418.3 nm, and 347.0 nm, however, for the 3c@PD NLC molecule, emission intensity peaks appeared at 429.6 nm, 418.0 nm and 329.0 nm. The stoke’s shift for 3b@PD LC mesophase varied between 0.01 eV to 0.613 eV while for 3c@PD NLC molecule it was found in between 0.317 eV to 0.453 eV. POM analysis unveiled distinct fan-like textures with varied colour interfaces. Time-resolved photoluminescence (TRPL) decay studies unveiled average lifetime of 3b@PD LC mesophase was 1.80 ns, 0.98 ns, 0.308 ns and for 3c@PD NLC molecule, the average lifetime was found to be 0.98 ns, 0.82 ns, and 0.306 ns at various excitation wavelengths. However, phosphorescence decay studies showed faster decay characteristics for 3c@PD NLC molecule (1.40 ns to 4.00 ns) compared with 3b@PD LC mesophase (1.65 to 5.42 ns) when excited at various wavelengths. The interaction between LC molecules and PTCDA demonstrated a significant enhancement in RTPL, TRPL, and SSPL properties, suggesting promising applications in photonics and optoelectronics.

A Class of Heptaphyrins with NIR Absorption Modulated by Metal Coordination and Nucleophilic Substitution.

The intensive interest in expanded porphyrins can be attributed to their appealing photoelectric and coordination behavior. In this work, an N-confused heptaphyrin 1 was synthesized by an acid-catalyzed [3+4] condensation reaction. The introduction of an N-confused pyrrolic unit into the heptaphyrin macrocycle led to the formation of a figure-eight-like conformation with nonsymmetrical "NNNN" and "NNNC" coordination cavities employable for bimetallic coordination. As a result, chelation of 1 with Zn(II) and Cu(II) afforded mono-Zn(II) complex 2 and bis-Cu(II) complex 3, respectively, with the metal atoms exhibiting distorted square-planar geometries. In complex 3, an oxygen atom is attached to the α-C atom of N-confused pyrrole D, and thus the N and C atoms of ring D participate in coordination within the two cavities. Interestingly, treatment of 1 with Cs2CO3 in MeOH resulted in regioselective substitution of all the seven para-F atoms in the meso-C6F5 groups as well as the α-H of ring D by eight methoxy moieties. Complex 3 displays a red-shifted absorption band edge of ca. 2200 nm, compared to that of ca. 1600 nm observed for 1. This work provides an example of incorporating an N-confused pyrrole to construct expanded porphyrins with distinctive coordination behavior and tunable NIR absorption.

Fluorenone-naphthyl encapsulated dual sensor for recognition of F− and Hg2+: Syngenetic effect with drug sobisis and molecular docking studies

A novel fluorenone-naphthyl pendant sensor (FTU) possessing thiourea functionality has been synthesized via a simple condensation method and utilized for the recognition of F− and Hg2+ ions in the solution of CH3CN. The addition of F− and Hg2+ ions to the FTU solution led to the appearance of red-shifted absorption bands at 340 and 315 nm, respectively. On the other hand, in the fluorescence spectrum, the two-fold decrease in fluorescence intensity of probe FTU was observed with F− ions; while complete quenching of the fluorescence intensity was noticed with Hg2+ ions at 423 nm. The limit of detection values of F− and Hg2+ ions were found to be 1.02 & 29.1 nM, respectively, measured by UV–vis studies and 0.0185 & 0.81 nM, respectively, measured by fluorescence studies, which are less than recommended by WHO. DFT computational assessments and 1H NMR titration experiments pointed to F− induced deprotonation of thiourea NH signals. However, the chelation-enhanced quenching effect (CHEQ) was held responsible for fluorescence quenching with Hg2+ addition. Moreover, the in-situ formed FTU + F− complex was utilized for secondary sensing of drug sobisis. Furthermore, the real-world applicability of sensor FTU has been successfully scrutinized for the recognition of F− ions in the toothpaste samples. In addition, molecular docking studies revealed that FTU exhibited excellent antibacterial potency towards different gram-positive as well as negative strains.

Rational Design of Far-Red Archaerhodopsin-3-Based Fluorescent Genetically Encoded Voltage Indicators: from Elucidation of the Fluorescence Mechanism in Archers to Novel Red-Shifted Variants.

Genetically encoded voltage indicators (GEVIs) have found wide applications as molecular tools for visualization of changes in cell membrane potential. Among others, several classes of archaerhodopsin-3-based GEVIs have been developed and have proved themselves promising in various molecular imaging studies. To expand the application range for this type of GEVIs, new variants with absorption band maxima shifted toward the first biological window and enhanced fluorescence signal are required. Here, we integrate computational and experimental strategies to reveal structural factors that distinguish far-red bright archaerhodopsin-3-based GEVIs, Archers, obtained by directed evolution in a previous study (McIsaac et al., PNAS, 2014) and the wild-type archaerhodopsin-3 with an extremely dim fluorescence signal, aiming to use the obtained information in subsequent rational design. We found that the fluorescence can be enhanced by stabilization of a certain conformation of the protein, which, in turn, can be achieved by tuning the pK a value of two titratable residues. These findings were supported further by introducing mutations into wild-type archeorhodopsin-3 and detecting the enhancement of the fluorescence signal. Finally, we came up with a rational design and proposed previously unknown Archers variants with red-shifted absorption bands (λmax up to 640 nm) and potential-dependent bright fluorescence (quantum yield up to 0.97%).

Screening novel candidates of ZL003-based organic dyes for dye-sensitized solar cells by modifying auxiliary electron acceptors: A theoretical study

In this work, a series of ZL003-based free-metal sensitizers with the donor-acceptor-π- conjugated spacer-acceptor (D-A-π-A) structure were designed by modifying auxiliary electron acceptors for the potential application in dye-sensitized solar cells. The energy levels of frontier molecular orbitals, absorption spectra, electronic transition, and photovoltaic parameters for all studied dyes were systematically evaluated using density functional theory (DFT)/time-dependent DFT calculations. Results illustrated that thienopyrazine (TPZ), selenadiazolopyridine (SDP), and thiadiazolopyridine (TDP) are excellent electron acceptors, and dye sensitizers functionalized by these acceptors have smaller HOMO-LUMO gaps, obviously red-shifted absorption bands and stronger light harvesting. The present study revealed that the photoelectric conversion efficiency (PCE) of ZL003 is around 13.42 % with a JSC of 20.21 mA·cm−2, VOC of 966 mV and FF of 0.688 under the AM 1.5G sun exposure, in good agreement with its experimental value (PCE = 13.6 ± 0.2 %, JSC = 20.73 ± 0.20 mA·cm−2, VOC = 956 ± 5 mV, and FF = 0.685 ± 0.005.). With the same procedure, the PCE values for M4, M6, and M7 were estimated to be as high as 19.93 %, 15.38 %, and 15.80 % respectively. Hence, these three dyes are expected to be highly efficient organic sensitizers applied in practical DSSCs.

Bathochromically shifted absorption and near IR emission in bismuth(III) porphyrins with meso-fluorophenyl and methoxyphenyl substitutions

A series of bismuth(III) porphyrins with varying degrees of electron-donating and electron-withdrawing groups in their meso-positions have been synthesized. All the porphyrins were synthesized successfully and characterized spectroscopically. The absorption studies reveal bathochromically shifted spectra, up to [Formula: see text]60 nm, compared to their corresponding free-base porphyrins which is common for [Formula: see text]-type hyperporphyrins. Interestingly, all the samples exhibited broad near-IR phosphorescence at room temperature. The spectroscopic studies indicate that the demetallation occurs in both solution and solid states to form corresponding free-base porphyrin and this process is much faster in meso-trimethoxyphenyl substituted bismuth(III) porphyrin. Nevertheless, the study reveals interesting optical properties of bismuth(III) porphyrins, particularly red-shifted absorption and near IR emission bands.

Novel phenothiazine-based amphiphilic Aza-BODIPYs for high-efficient photothermal therapy

Photothermal therapy (PTT) is one of innovative therapeutics types that have been widely applied in cancer treatment, antibiosis and insecticide. It is of significance to investigate photothermal conversion agents (PCAs) with outstanding photothermal conversion ability, photostability and biocompatibility. Here, we developed three novel phenothiazine-based aza-BODIPYs for high-efficient PTT applications. Phenothiazine, as the electron-donating moiety, was introduced into aza-BODIPY core to achieve red-shifted absorption band (∼20–40 nm) with λmax at 730–745 nm and high molar extinction efficient (105 M−1 cm−1). TEG linker was decorated for further increasing the hydrophilicity and biocompatibility of aza-BODIPYs. After self-assembly, the nanoparticles exhibited the preferable photothermal conversion efficient (53–63%) and high photostability with the appropriate hydrated sizes (60–110 nm) and homogenous morphologies. Finally, the aza-BODIPY nanoparticles can significantly decrease the HeLa cell viability under 808 nm laser irradiation, but have the negligible cytotoxicity in dark environments. The series of phenothiazine-based aza-BODIPY PCAs have much potential for the more applications of clinic photothermal therapy in future.

Fluorescent Molecular Rotors Based on Hinged Anthracene Carboxyimides.

Temperature and viscosity are essential parameters in medicine, environmental science, smart materials, and biology. However, few fluorescent sensor publications mention the direct relationship between temperature and viscosity. Three anthracene carboxyimide-based fluorescent molecular rotors, 1DiAC∙Cl, 2DiAC∙Cl, and 9DiAC∙Cl, were designed and synthesized. Their photophysical properties were studied in various solvents, such as N, N-dimethylacetamide, N, N-dimethylformamide, 1-propanol, ethanol, dimethyl sulfoxide, methanol, and water. Solvent polarizability resulted in a solvatochromism effect for all three rotors and their absorption and emission spectra were analyzed via the Lippert-Mataga equation and multilinear analysis using Kamlet-Taft and Catalán parameters. The rotors exhibited red-shifted absorption and emission bands in solution on account of differences in their torsion angle. The three rotors demonstrated strong fluorescence in a high-viscosity environment due to restricted intramolecular rotation. Investigations carried out under varying ratios of water to glycerol were explored to probe the viscosity-based changes in their optical properties. A good linear correlation between the logarithms of fluorescence intensity and solution viscosity for two rotors, namely 2DiAC∙Cl and 9DiAC∙Cl, was observed as the percentage of glycerol increased. Excellent exponential regression between the viscosity-related temperature and emission intensity was observed for all three investigated rotors.

A Quadruply Bridged Non-Offset Face-to-Face Porphyrin Dimer and Cross-Shaped Pentameric Porphyrin Tapes Based on 2,7,12,17-Tetrakis(pinacolatoboryl) NiII Porphyrin.

2,7,12,17-Tetrakis(pinacolatoboryl) NiII porphyrin 5 Ni was synthesized in 75 % yield by Ir-catalyzed borylation of porphine followed by NiII metalation and has been demonstrated to be a useful synthon, giving 2,7,12,17-tetraaryated NiII porphyrins 6 a-d, peripherally octaarylated NiII porphyrins 8 a-d, quadruply bridged face-to-face non-offset NiII -porphyrin dimer 12, and cross-shaped β-meso singly linked porphyrin pentamers and nonamers. Oxidation of cross-shaped β-meso singly linked porphyrin pentamers 14 Ni and 14 Zn gave fused pentameric tapes 15 Ni and 15 Zn. The structures of 12, 14 Zn, and 15 Ni have been revealed by X-ray diffraction analysis. Optical separation of 12 has been accomplished, showing a bisignate coupling pattern for exciton-coupled blue-shifted Soret band. Pentameric porphyrin tape 15 Zn exhibits a red-shifted absorption band at 1156 nm and seven reversible redox waves.

Red Light Absorption of [ReI(CO)3(α-diimine)Cl] Complexes through Extension of the 4,4'-Bipyrimidine Ligand's π-System.

Rhenium(I) complexes of type [Re(CO)3(NN)Cl] (NN = α-diimine) with MLCT absorption in the orange-red region of the visible spectrum have been synthesized and fully characterized, including single crystal X-ray diffraction on two complexes. The strong bathochromic shift of MLCT absorption was achieved through extension of the π-system of the electron-poor bidiazine ligand 4,4'-bipyrimidine by the addition of fused phenyl rings, resulting in 4,4'-biquinazoline. Furthermore, upon anionic cyclization of the twisted bidiazine, a new 4N-doped perylene ligand, namely, 1,3,10,12-tetraazaperylene, was obtained. Electrochemical characterization revealed a significant stabilization of the LUMO in this series, with the first reduction of the azaperylene found at E1/2(0/-) = -1.131 V vs. Fc+/Fc, which is the most anodic half-wave potential observed for N-doped perylene derivatives so far. The low LUMO energies were directly correlated to the photophysical properties of the respective complexes, resulting in a strongly red-shifted MLCT absorption band in chloroform with a λmax = 586 nm and high extinction coefficients (ε586nm > 5000 M-1 cm-1) ranging above 700 nm in the case of the tetraazaperylene complex. Such low-energy MLCT absorption is highly unusual for Re(I) α-diimine complexes, for which these bands are typically found in the near UV. The reported 1,3,10,12-tetraazaperylene complex displayed the [Re(CO)3(α-diimine)Cl] complex with the strongest MLCT red shift ever reported. UV-Vis NIR spectroelectrochemical investigations gave further insights into the nature and stability of the reduced states. The electron-poor ligands explored herein open up a new path for designing metal complexes with strongly red-shifted absorption, thus enabling photocatalysis and photomedical applications with low-energy, tissue-penetrating red light in future.

The influence of structural effects and the solvent properties on spectral, generation characteristics, photostability and lipophilicity of 1,3,5,7-tetramethyl-BODIPY and its alkylated and iodinated derivatives

This paper presents the results of a comparative analysis of the effect of iodination features, meso-substitution of 1,3,5,7-tetramethyl-BODIPY, and the solvent properties on the spectral, generation properties, photostability and lipophilicity of boron(III) dipyrromethenates. Like most alkyl-substituted BODIPYs, the BDP1-BDP3 dipyrromethenates exhibit intense emission properties with fluorescence quantum yields of 40–100 %. However, they are practically not endowed with the ability to generate singlet oxygen (1O2), showing ФΔ values of 0–9 %. Iodinated derivatives BDP4–BDP7 revealed a strong heavy atom effect resulting in the red-shifted (up to 37 nm and 46 nm, respectively) absorption and emission bands, fluorescence quenching with φfl values of about 2–28 %, a decrease (up to 4.38 times) in photostability, but increasing the ability to generate singlet oxygen with excellent ФΔ values of 0.73–0.93 and 0.76–0.98 in 1-octanol and ethanol, respectively. The introduction of a –(CH2)3COOCH3 substituent into the meso-position of the alkyl- and iodo-substituted luminophores BDP3 and BDP7 make it possible to increase the UV stability of the dyes up to 3 times due to the screening of the carbon atom of the methine meso-spacer, which is one of the most photoactive centres of dipyrromethene dyes. In addition, meso-substitution enhances the lipophilicity of BDP3 and BDP7 by almost ∼1.5 times compared to meso-unsubstituted BDP1 and BDP6 analogues. The results of the studies indicate that the introduction of the –(CH2)3COOCH3 substituent into the diiodine-BODIPY meso-position provides a combination of photostability, efficiency of singlet oxygen generation, and lipophilicity that is optimal for a PDT agent.

A novel and sensitive ratiometric fluorescent quantum dot-based biosensor for alkaline phosphatase detection in biological samples via the inner-filter effect.

Alkaline phosphatase (ALP) is an important biomarker whose abnormal level in activity is associated with hepatobiliary, skeletal, and renal diseases as well as cancer. Herein, we synthesized ZnSe@ZnS quantum dots (ZnSe@ZnS QDs) and Mn-doped ZnS quantum dots (Mn:ZnS QDs) as fluorophores to establish the ratiometric fluorescent assay for ALP activity detection in biological samples. p-Nitrophenyl phosphate (PNPP) was used as a substrate for ALP, and the overlaps between absorption spectra of PNPP and excitation spectra of QDs resulted in sharp fluorescence quenching. Under the catalysis of ALP, PNPP was hydrolyzed into p-nitrophenol (PNP), which caused a red shift of absorption band of PNPP and fluorescence recovery of Mn:ZnS QDs (585 nm). However, the overlaps between absorption spectra of PNP and emission spectra of ZnSe@ZnS QDs led a further quenching of ZnSe@ZnS QDs (405 nm). Therefore, the ratiometric fluorescent signals (F 585/F 405) were associated with activity of ALP based on bidirectional responses of QDs to the concentration of PNPP. Under the optimum conditions, the method exhibited a good linear relationship from 4 to 96 U per L (R 2 = 0.9969) with the detection limit of 0.57 U per L. Moreover, the method was successfully applied for detecting the ALP activity in a complex biological matrix (human serum and HepG2 cells) with impressive specificity. In particular, the complicated chemical modifications of QDs and pretreatments of biological samples were not required in the whole detection procedures. Therefore, it not only provided a sensitive, specific and simple approach to clinical ALP activity detection, but it also provided support for early diagnosis of diseases.

D-π-A structured porphyrin sensitizers for dye-sensitized solar cells

Two porphyrin-based D-[Formula: see text]-A structured dyes of SGT-026 and SGT-027 with different acceptor groups were synthesized and characterized for dye-sensitized solar cells. The structure of SGT-027was designed with a very strong acceptor unit of (5-(naphtho[1,2-c:5,6-c[Formula: see text]]bis[1,2,5]-thiadiazolyl)benzoic acid) (NBTD), resulting in more red-shifted absorption bands and broader NIR absorption ability, but SGT-026 porphyrin with a weak acceptor unit of (2-(thieno[3,4-c]pyrrole-4,6(5H)-dionyl)benzoic acid) (TPD) exhibited a blue-shifted Q band absorption, compared to the reference SGT-021dye with a strong acceptor unit of (4-(benzo[c][1,2,5]thiadiazol-4-yl)benzoic acid) (BTD). The photophysical properties of these D-[Formula: see text]-A structured porphyrin sensitizers depend on the degree of the intramolecular charge transfer character with the electron-withdrawing ability order of NBTD> BTD> TPD. The photovoltaic performances were evaluated using cobalt (II/III)-based redox electrolyte, SGT-027 reached a power conversion efficiency (PCE) of up to 7.5%, which was surprisingly inferior to the benchmark porphyrin sensitizer SGT-021 with a PCE of 10.9%, and a PCE of 5.9% was exhibited by SGT-026, under AM 1.5G sunlight. The optical, and electrochemical properties and DFT calculations were utilized to understand the cell performance difference between SGT-dyes.

Enhanced dielectric and supercapacitive properties of spherical like Sr doped Sm2O3@CoO triple oxide nanostructures

Integrating the hybrid nanostructures exhibiting enhanced storage and electrical properties requires tuning of composition of constituents. To address this issue, we prepared Sr2+ nanoparticles (NPs) decorated over Sm2O3@CoO nanostructures (NS) by chemical precipitation. The structure integrity of the composite was determined by analytical tools. Based on the strongest peak of X-ray diffraction (XRD), crystallite size of the nanoparticles was determined to be 26.14 nm, indicating a mixed phase of monoclinic and tetragonal crystal formation. FESEM revealed a spherical-like morphology with a homogeneous distribution of microstructures with average sizes ranging from 68 nm to 60 nm. The optical absorptivity revealed a redshift in absorption bands centred at 337.0 nm, 343.9 nm, and 353.0 nm in UV-region. The optical band gap of NS was found to be in the range of 3.38 eV to 3.15 eV, and the BET surface area of Sr15%:Sm2O3@CoO was found to be 458–469 cm2/g with a corresponding pore size of 13.17 nm. All Sr-doped Sm2O3@CoO NS exhibited higher ionic conductivity and dielectric constant than undoped material. In an aqueous KOH electrolyte, the NS showed a specific capacity of 234.2C/g (65.1mAh/g) demonstrating the material as potential candidate in energy storage and dielectrics.

New A3B-type naphthyl Zn(II) porphyrins as DSSC dyes: Effect of anchoring group and co-adsorption for enhanced efficiency

Two new Zn(II) porphyrin dyes ZnNPCA and ZnNPHy bearing three naphthyl groups and one carboxyphenyl/hydroxyphenyl anchoring group in an A3B meso substitution pattern was synthesized utilizing a mixed condensation approach. The redshifted absorption bands to 427 nm as impacts on the extended conjugation with three naphthyl substituents. Similarly, the emission spectrum also exhibits a redshift than ZnTPP-COOH dye. The anodic shift was found in the reduction potential of the naphthyl dyes with the carboxylic acid anchor (ZnNPCA), facilitating the more favourable electron injection. Moreover, the naphthyl porphyrin dyes positively interacted with semiconducting TiO2, whose binding mode was further established using FT-IR. While interacting with titania, the more broadening absorption spectra exhibit strong electronic coupling and will benefit the electron injection. The high dye loading amount obtained for ZnNPCA dye was 13.1 × 10−8 mol cm2, which is more significant towards light harvesting. DSSC devices were fabricated using porphyrin-sensitized photoanodes. ZnNPCA showed better efficiency than ZnNPHy owing to higher dye loading onto the titania surface. Furthermore, the influence of co-adsorbent DCA on the photovoltaic performance of the fabricated DSSC devices was investigated. As a result, a maximum efficiency of 1.85% was achieved for ZnNPCA/DCA device. In addition, electrochemical impedance spectroscopy results revealed a higher electron lifetime (6.14 ms) for this device, supporting better suppression of back reactions.

Synthesis of 2,2′-biphenyl-fused porphyrins: Installation of directly fused seven-membered ring

2,2[Formula: see text]-Biphenyl-fused Ni(II) porphyrins were synthesized by two methods. One was oxidative fusion reaction of meso-(biphen-2-yl)-substituted Ni(II) porphyrin with the combination of 2,3-dichloro-5,6-dicyano-[Formula: see text]-benzoquinone (DDQ) and Sc(OTf)3 and the other was Pd-catalyzed intramolecular cyclization of meso-(2[Formula: see text]-chlorobiphen-2-yl)-substituted Ni(II) porphyrin. These fused products showed contorted structures owing to the installed seven-membered carbocycle(s) that were revealed by X-ray crystallographic analysis and exhibited moderately red-shifted absorption bands.

Phosphonium-Based Ionic Thermally Activated Delayed Fluorescence Emitters for High-Performance Partially Solution-Processed Organic Light-Emitting Diodes

Phosphonium-Based Ionic Thermally Activated Delayed Fluorescence Emitters for High-Performance Partially Solution-Processed Organic Light-Emitting Diodes

J-aggregates albumin-based NIR-II fluorescent dye nanoparticles for cancer phototheranostics.

Phototheranostics, relying on energy conversions of fluorophores upon excitation, integrating diagnostic fluorescence imaging and photo-driven therapy, represents a promising strategy for cancer precision medicine. Compared with the first near-infrared biological window (NIR-I), fluorophores imaged in the second window (NIR-II, 1000–1700 ​nm) exhibit a higher temporal and spatial resolution and tissue penetration depth. Polymethine cyanine-based dye IR1061 is a typical NIR-II small-molecule organic fluorophore, but its low water solubility and short circulation time limiting its biological applications. Therefore, human serum albumin (HSA) nanoparticles with great biocompatibility and biosafety were employed to fabricate hydrophobic IR1061, which exhibited red-shifted absorption band as typical for J-aggregates. Moreover, IR1061@HSA nanoparticles can be successfully used for NIR-II imaging to noninvasively visualize the tumor vascular networks, as well as real-time intraoperative image-guided tumor resection. Interestingly, benefiting from the high photothermal conversion efficiency brought by J-aggregates, IR1061@HSA nanoparticles were also explored for photothermal therapy (PTT) and cause efficient thermal ablation of tumors. Overall, IR1061@HSA, as a novel J-aggregates albumin-based NIR II dye nanoparticle with high biocompatibility, provides an integrated versatile platform for cancer phototheranostics with promising clinical translation prospects.