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Electrical detection of plasmon-induced isomerization in molecule–nanoparticle network devices
摘要： We use a network of molecularly linked gold nanoparticles (NPSAN: nanoparticle self-assembled network) to demonstrate the electrical detection (conductance variation) of plasmon-induced isomerization (PII) of azobenzene derivatives (azobenzene bithiophene: AzBT). We show that PII is more efficient in a 3D-like NPSAN (cluster-NPSAN) than in a purely two-dimensional NPSAN (i.e., a monolayer of AzBT functionalized Au NPs). By comparison with the usual optical (UV-visible light) isomerization of AzBT, PII shows faster (a factor > ～10) isomerization kinetics. Possible PII mechanisms are discussed: electric field-induced isomerization, two-phonon process, and plasmon-induced resonance energy transfer (PIRET), the latter being the most likely.
关键词： azobenzene derivatives,nanoparticle networks,electrical detection,plasmonics,plasmon-induced isomerization
更新于2025-09-19 17:15:36
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Crystal Structures and Optical Properties of Two Novel 1,3,5-Trisubstituted Pyrazoline Derivatives
摘要： Two novel 1,3,5-trisubstituted pyrazoline derivatives—1-acetyl-3-(4-methoxyphenyl)-5-(6-methoxy-2-naphthyl)-pyrazoline (2a) and 1-(4-nitrophenyl)-3-(4-methoxyphenyl)-5-(6-methoxy-2-naphthyl)-pyrazoline (2b)—were synthesized and their structures were determined by single crystal X-ray crystallography. Both of the two crystals exhibit twisted structures due to the large dihedral angles between the pyrazolinyl ring and the aromatic ring at the 5-position (88.09° for 2a and 71.26° for 2b). The optical–physical properties of the two compounds were investigated. The fluorescent emission of 2b arises from the 1,3-disubstituted pyrazoline chromophores and exhibits a red shift in polar solvents and solid-state, which could be attributed to photo-induced intramolecular charge transfer (ICT) from N1 to C3 in the pyrazoline moiety and the intermolecular interactions within the crystal. The fluorescent emissions of 2a (λmax 358–364 nm) in solvents and solid-state both come from 6-methoxy-2-naphthyl chromophores, which are fairly insensitive to the solvent polarity.
关键词： fluorescence,single crystal,pyrazoline derivatives
更新于2025-09-19 17:15:36
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Theoretical design, synthesis and studies on the solvatochromic behaviour of low band gap phenylenevinylene based copolymers
摘要： A new series of low band gap phenylenevinylene based copolymers was designed by employing density functional theory in the periodic boundary condition using HSE06 exchange correlation functional using 6-31G basis set and synthesized via the Gilch polymerization. The theoretical band gap of the copolymers MD-CA-PPV, MD-FL-PPV, MD-PT-PPV and MD-AN-PPV were found to be 1.98, 2.07, 2.31 and 1.99 eV respectively using the DFT/HSE06/6-31G calculation and the optical band gap of 1.96, 2.03, 2.01 and 1.98 eV respectively, according to the onset edge of lower energy peak of the polymers in solution. The experimental results supported the theoretical prediction. Solvatochromic behaviour of the synthesized copolymers was studied thoroughly in toluene/acetonitrile mixtures of varying polarity at room temperature. The absorption spectrum of the PPV polymers was sensitive to solvent effects which showed bathochromic and hypsochromic shifts with increasing solvent polarity indicating that the transitions involved were π-π* and n-π*. The ground and excited state dipole moments were calculated using solvatochromic correlations. Onsager radius determined from ab initio calculation was used in the determination of dipole moments. The change in the dipole moment (Δμ) was calculated both from solvatochromic shift method and on the basis of microscopic empirical solvent polarity parameter (ET(30)) and values are compared. It was observed that the excited state dipole moment (μe) was larger than its ground state (μg) counterpart. This indicated that a substantial redistribution of the π-electron densities occurred in the more polar excited state for the selected phenylenevinylene polymers. The third-order nonlinear optical (NLO) properties of the copolymers, evaluated by Z-scan method with nanosecond laser beam at 532 nm, are reported. The nonlinear absorption coefficient of the copolymers were calculated to be 0.17×10-10, 2.06 × 10-10, 0.63 × 10-10 and 2.83 × 10-10 esu, respectively for MD-CA-PPV, MD-FL-PPV, MD-PT-PPV and MD-AN-PPV which certified that the polymers showed semiconductor properties.
关键词： Nonlinear optical properties,Solvatochromic properties,Gilch polymerisation,Density functional theory,Poly(p-phenylenevinylene) derivatives
更新于2025-09-19 17:15:36
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Organic Light-Emitting Diodes based on Benzo[ <i>q</i> ]quinoline Derivatives
摘要： In this study, we synthesized two emitting materials based on benzo[q]quinoline derivatives. OLED devices using these materials were facricated in the following sequence;ITO(180nm)/4,4’,4’’-Tris[2-naphthyl(phenyl)amino]triphenylamine(2-TNATA)(30nm)/N,N’-di(1-naphthyl)-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine(NPB)(20nm)/Emitting materials(30nm)/4,7-diphenyl-1,10-phenanthroline (Bphen) (30nm)/Liq(2nm)/Al(100nm). Particularly, a device using 2,4-di(naph-talene-1-yl)benzo[q]quinoline as an emitter exhibited the efficient emission with a luminous efficiency, a power efficiency, and exteranl quantum efficiency of, and the CIE coordinates of 2.91cd/A, 0.99lm/W, 0.90% at 20mA/cm2, and (0.33, 0.55) at 1000cd/m2, respectively. Interestingly, emissions from electromers and electroplexes were shown to be crucial role in electroluminescences from benzo[q]qui-noline derivatives
关键词： benzo[q]quinoline derivatives,OLED,Electroluminescence
更新于2025-09-19 17:13:59
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Blue electroluminescent materials based on indeno[1,2-a]arene derivatives for Organic Light-Emitting Diodes
摘要： In this study, as a continuous effort for searching efficient blue-emitting materials, we designed and synthesized materials based on indeno[1,2-a]arene. OLED devices using these materials were fabricated in the following sequence; ITO (180 nm)/N,N’-diphenyl-N,N’-(2-napthyl)-(1,1’-phenyl)-4,4’-diamine (NPB) (50 nm)/emitting materials (30 nm)/4,7-diphenyl-1,10-phenanthroline (Bphen) (30 nm)/Liq/Al (2/100 nm). Particularly, a device using 7,7-dimethyl-7H-indeno[1,2-a]pyrene as emitter showed maximum values of luminous efficiency, power efficiency, and external quantum efficiency of 1.10 cd/A, 0.49 lm/W, 1.47% at 20 mA/cm2, respectively with CIE (x,y) coordinates of (0.15, 0.08) at 6.0V.
关键词： pyrene,blue OLED,electroluminescence,fluorescence,indeno[1,2-a]arene derivatives
更新于2025-09-19 17:13:59
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Asymmetric anthracene derivatives as multifunctional electronic materials for constructing simplified and efficient non-doped homogeneous deep blue fluorescent OLEDs
摘要： Herein, large π-conjugated core anthracene with an innate bipolar property was employed to construct multifunctional organic electronic materials. Delicate manipulating molecules via combining anthracene core and large periphery groups, two asymmetric anthracene derivatives namely (4-(10-(4-(9H-1,5-diazacarbazole-9-yl)phenyl)anthracen-9-yl)phenyl)diphenylphosphine oxide (p-PO15NCzDPA) and (3-(10-(3-(9H-1,5-diazarcarbazole-9-yl)phenyl)anthracen-9-yl)phenyl)diphenylphosphine oxide (m-PO15NCzDPA) were firstly designed and developed. The large periphery groups 1,5-diazarcarbazole (15NCz) and diphenylphosphine oxide (PO) efficiently interrupt the intramolecular π-conjugation, presenting an asymmetric bulky periphery enveloping strategy achieving highly twisted structures, which help to realize deep-blue emission. Meanwhile, due to the high PLQY and well-balanced bipolar transport characteristics, desired device addressing the contradiction of efficiency, color gamut and structure complexity is within reach. Detailed device engineering study was carried out, in which p-PO15NCzDPA and m-PO15NCzDPA were functioned as multifunction layers. As expected, p-PO15NCzDPA-based homogenous and unilateral homogenous OLEDs exhibited outstanding performance with impressive EQEmax of 4.55% and 6.40%, deep blue CIE coordinates of (0.152, 0.075) and (0.151, 0.066) at the voltage of 6 V, narrow FWHM of 46 nm and 50 nm, respectively. More importantly, the simplified homogenous device achieved extremely low efficiency roll-offs of 1.3% and 4.8% at 1000 and 5000 cd m-2, respectively. These results are among the most outstanding performance, which provided a guide for further improving the performance of deep blue fluorescent OLEDs and simplifying the structure of OLEDs.
关键词： asymmetric anthracene derivatives,homogenous device structure,multifunctional materials,deep-blue emission,fluorescent OLEDs
更新于2025-09-19 17:13:59
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Thermally Activated Delayed Fluorescence Benzyl Cellulose Derivatives for Nondoped Organic Light-Emitting Diodes
摘要： Thermally activated delayed ?uorescence (TADF) benzyl cellulose derivatives (TBC-X), which contained both carbazole (host) and phthalimide-based TADF dye (guest) moieties, were prepared from 2,3-di-O-benzyl cellulose in high yields. The TBC-X samples were soluble in common organic solvents such as CH2Cl2, CHCl3, THF, and toluene. The photoluminescence spectra of TBC-X spin-coated ?lms had a single emission peak derived only from guest moieties, which indicated e?cient energy transfer from the host to guest moieties. The TBC-10 (with a content of host and guest moieties of 93 and 7, respectively) in a spin-coated ?lm had the highest photoluminescence quantum yield of 55.3% and TADF characteristics. A nondoped organic light-emitting diode with TBC-10 as the emitting layer showed green emission (λ EL = 517 nm) and achieved a maximum external quantum e?ciency of 5.9%.
关键词： Thermally activated delayed ?uorescence,TADF,organic light-emitting diodes,benzyl cellulose derivatives,OLEDs
更新于2025-09-19 17:13:59
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Synthesis, radiolabelling and initial biological characterisation of <sup>18</sup> F-labelled xanthine derivatives for PET imaging of Eph receptors
摘要： Eph receptor tyrosine kinases, particularly EphA2 and EphB4, represent promising candidates for molecular imaging due to their essential role in cancer progression and therapy resistance. Xanthine derivatives were identified to be potent Eph receptor inhibitors with IC50 values in the low nanomolar range (1–40 nm). These compounds occupy the hydrophobic pocket of the ATP-binding site in the kinase domain. Based on lead compound 1, we designed two fluorine-18-labelled receptor tyrosine kinase inhibitors ([18F]2/3) as potential tracers for positron emission tomography (PET). Docking into the ATP-binding site allowed us to find the best position for radiolabelling. The replacement of the methyl group at the uracil residue ([18F]3) rather than the methyl group of the phenoxy moiety ([18F]2) by a fluoropropyl group was predicted to preserve the affinity of the lead compound 1. Herein, we point out a synthesis route to [18F]2 and [18F]3 and the respective tosylate precursors as well as a labelling procedure to insert fluorine-18. After radiolabelling, both radiotracers were obtained in approximately 5% radiochemical yield with high radiochemical purity (>98%) and a molar activity of >10 GBq μmol?1. In line with the docking studies, first cell experiments revealed specific, time-dependent binding and uptake of [18F]3 to EphA2 and EphB4-overexpressing A375 human melanoma cells, whereas [18F]2 did not accumulate at these cells. Since both tracers [18F]3 and [18F]2 are stable in rat blood, the novel radiotracers might be suitable for in vivo molecular imaging of Eph receptors with PET.
关键词： xanthine derivatives,molecular imaging,positron emission tomography (PET),fluorine-18-labelled,Eph receptor tyrosine kinases
更新于2025-09-19 17:13:59
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Interfacial Bridge Using a <i>cis</i> ‐Fulleropyrrolidine for Efficient Planar Perovskite Solar Cells with Enhanced Stability
摘要： Fullerene derivatives, especially after purposely functionalization, have potential to efficiently passivate interfacial defects between perovskites and electron transport layers. In this work, a fullerene derivative with amine functional group, 2,5-diphenyl C60 fulleropyrrolidine (DPC60), is synthesized and employed as an interfacial layer between a perovskite and SnO2 in planar perovskite solar cells (PSCs). The cis-configuration and the specific amine group of DPC60 effectively enhance the chemical interaction between the perovskite and DPC60, promoting the passivation of perovskite defects at the interface. The suitable energy level of DPC60 and the improved conductivity of the SnO2/DPC60 film facilitate the electron extraction from the perovskite layer. As a result, PSCs incorporated with DPC60 reach a PCE of 20.4% with high reproducibility, which is much higher than that of the bare SnO2 based devices (18.8%). Furthermore, the hydrophobic DPC60 layer suppresses heterogeneous nucleation and improves the crystallinity of the perovskite film, resulting in better device stability, retaining 82% of its initial efficiency after 200 h of 1 sun continuous irradiation and thermal ageing (55 ± 5 °C).
关键词： fullerene derivatives,chemical interactions,perovskite solar cells,passivation,energy level alignment
更新于2025-09-19 17:13:59
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Triphenylamine dibenzofulvene–derived dopant‐free hole transporting layer induces micrometer‐sized perovskite grains for highly efficient near 20% for p‐i‐n perovskite solar cells
摘要： This paper discusses a series of triphenylamine dibenzofulvene–based hole transporting materials (HTMs) featuring different numbers of MeO groups (none for YC‐1, four for YC‐2, and six for YC‐3) and their use in p‐i‐n perovskite solar cells (PSCs). We investigated the optoelectronic properties of these HTMs and found that the PSC devices incorporating YC‐1 as HTMs exhibited power conversion efficiencies (PCEs) of 15.78 ± 0.61%, which outperformed the corresponding PEDOT:PSS‐based device (12.80 ± 1.31%) under similar testing conditions. We then employed YC‐1 for the interfacial modified layer of a NiOx‐derived PSC having the structure ITO/NiOx/YC‐1/CH3NH3PbI3/PC61BM/bathocuproine/Ag. The presence of YC‐1 promoted the growth of micrometer‐sized grains of perovskite and induced a lower content of grain boundary defects, both of which improved the carrier extraction. Thereby, compared with conventional NiOx device, we observed a great increase in the PCE, from 17.16 ± 0.68% to 18.81 ± 0.42%, with a champion cell displaying a PCE of 19.37% (with negligible hysteresis). The corresponded device exhibited a stabilized efficiency of approximately 19% after storage in the dark at 25°C under argon for over 1000 hours. This study suggests a new approach for designing the high‐performance stable p‐i‐n PSCs.
关键词： methoxy groups,p‐i‐n perovskite solar cells,bilayered inorganic/organic HTMs,triphenylamine dibenzofulvene derivatives
更新于2025-09-19 17:13:59