Calculation of Visible Absorption Maxima of Phthalocyanine Compounds by Quantum Theory

Based on HYPERCHEM, the structures of five phthalocyanie compounds were optimized with PM3 and their visible absorption maxima were calculated with ZINDO/S method by selecting appropriate p-p overlap weighting factor (OWFp-p), the agreement with experiment was excellent. The relationship between OWF- and molecular structure parameters was obtained by the method of stepwise regression and was explained in terms of quantum theory. OWF-=0.58126+0.04562ANC1+0.03839X. Where, ANC1 and X are the symbols of average net charges on coordinated bonded nitrogens and electronegativity of central atom, respectively.

Study on the prediction of visible absorption maxima of azobenzene compounds

The geometries of azobenzene compounds are optimized with B3LYP/6-311G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respectively. The results agree well with the observed values. It was found that for the calculation of visible absorption using ZINDO/S method could rapidly yield better results by adjusting OWFπ-π (the relationship between π-π overlap weighting factor) value than by the TD-DFT method. The method of regression showing the linear relationship between OWFπ-π and BLN-N (nitrogen-nitrogen bond lengths) as OWFπ-π=?8.1537+6.5638BLN-N, can be explained in terms of quantum theory, and also be used for prediction of visible absorption maxima of other azobenzne dyes in the same series. This study on molecules’ orbital geometry indicates that their visible ab- sorption maxima correspond to the electron transition from HOMO (the highest occupied molecular orbital) to LUMO (the lowest unoccupied molecular orbital).

Preparation of Organic Semiconductor PTCDA and Studies on Its Crystal Structure and the Absorption Spectrum

Organic semiconductoe 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) has been synthetized with 1,8-naphthalic anhydride using chemical method.X-ray diffraction spectrum shows that it is monoclinic.Visible absorption spectrum shows that its gap band is 2.2 eV with singlet exciton bandwidth of 0.9 eV.

In Vitro Interaction of Nicotine and Hemoglobin under Liver Cell Metabolizing Condition

The in vitro interaction of nicotine and hemoglobin (Hb) in a metabolizing System was studied by spectroscopy assays. Visible spectra showed two isobestics, and fluorescence spectra showed static quenching with increasing of nicotine dose. Meanwhile, the CD spectra intensity reduced, showing the conformation of Hb varied markedly through the interaction. All these results suggested that the interaction of nicotine or its metabolites and Hb might do harm to physicological function of Hb.

Spectroscopic and Electrochemical Studies of the Interaction Between Fuchsin Basic and DNA

Visible spectroscopic and electrochemical methods were used to study the interactions between DNA and fuchsin basic（FB）. FB has an irreversible electro-oxidation peak in 5 mmol/L Tris-HCl buffer solution at pH = 7.4 on a glassy carbon electrode（GCE）. After adding certain concentration of dsDNA, the oxidation peak current of FB decreases, but the peak potential hardly changes. The visible absorption spectroscopic study shows that the binding mode of FB to dsDNA is intercalative binding and electrostatic binding when the ratio of the concentration of dsDNA to FB is smaller than 0. 2, and anew substance, which produces a new absorption peak, is obtained via a covalent binding between dsDNA and FB apart from intercalative binding and electrostatic binding when the ratio of the concentration of dsDNA to FB is larger than 0. 2. The visible absorption spectra varies no longer when the ratio of the concentration of dsDNA＇to FB is larger than 1.5. A mean binding ratio of dsDNA to FB was determined to be 1.4： 1, suggesting that two complexes FB-dsDNA and FB-2dsDNA be formed. The interaction between FB and ssDNA was only electrostatic binding. The more powerful interaction of FB with dsDNA than with ssDNA may be applied for the recognition of dsDNA and ssDNA, and in DNA biosensor as hybridization indicator.

Supra-(carbon nanodots) with a strong visible to near-infrared absorption band and efficient photothermal conversion

A novel concept and approach to engineering carbon nanodots(CNDs)were explored to overcome the limited light absorption of CNDs in low-energy spectral regions.In this work,we constructed a novel type of supra-CND by the assembly of surface charge-confined CNDs through possible electrostatic interactions and hydrogen bonding.The resulting supra-CNDs are the first to feature a strong,well-defined absorption band in the visible to near-infrared(NIR)range and to exhibit effective NIR photothermal conversion performance with high photothermal conversion efficiency in excess of 50%.

CsPbBr_3 perovskite quantum dots: saturable absorption properties and passively Q-switched visible lasers

This work presents the saturable absorption(SA) properties of CsPbBr_3 perovskite quantum dots(QDs). The perovskite QDs show excellent SA performance with a nonlinear absorption coefficient of-35 × 10^(-2) cm∕GW and a figure of merit of 3.7 × 10^(-14) esu cm. Further, their use as saturable absorbers in a passively Q-switched visible solid-state laser for the generation of soliton pulses is demonstrated. These results demonstrate thepotential for the perovskite QDs to act as saturable absorbers.

Simultaneous Raman and reflection UV/Vis absorption spectroelectrochemistry

In the present work,a new combination of Raman and ultraviolet and visible(UV/Vis)absorption spectroelectrochemistry in reflection mode is proposed.The new experimental setup allows obtaining the two kinds of spectroscopic data without interferences concomitantly with the electrochemical information.To the best of our knowledge,it is the first time to report the simultaneous obtention of electrochemical,electronic,and vibrational information in the same experiment.This new combination provides time-resolved information about the processes that are taking place on the electrode/solution interface which has significant implications in different fields of chemistry,such as modification of electrodes,studies of electrocatalytic reaction mechanisms,development of sensors,among others.Two different systems were used to demonstrate the advantages and capabilities of the brand-new technique,namely,the oxidation of potassium ferrocyanide,an out-sphere system that is usually employed in the validation of SEC techniques,and the electrochemical-surface enhanced Raman spectroscopy(EC-SERS)detection of crystal violet by in-situ formation of the silver SERS substrate,where the UV/Vis spectra were used to follow the formation of the SERS substrate,whereas the Raman response of a probe molecule was used to confirm either the formation of a nanostructured surface and to obtain the fingerprint of the molecule with a high time resolution.The brand-new experimental setup has shown to be useful,versatile,robust,compact,and easy to use for future applications.

Sensitizing photoactive metal-organic frameworks via chromophore for significantly boosting photosynthesis

Photosensitization related to energy/electron transfer process is of great importance to natural photosynthesis.Herein,we proposed a promising strategy to improve the sensitizing ability of the typical photoactive MOFs(UiO-Ir)by engineering its metal coordination center with NBI(1,8-naphthalenebenzimidizole)chromophore.The resulting MOFs(UiO-Ir-NBI)exhibited a strong sensitizing ability for significantly boosting photosynthesis.Impressively,the catalytic yield of 2-chloroethyl ethyl sulfoxide with UiO-Ir-NBI can reach 99%,over 6 times higher than that with UiO-Ir(16.4%).Moreover,UiO-Ir-NBI exhibited an excellent catalytic stability and a broad substrate tolerance,highlighting its great application prospect.Systematic investigations revealed that the strong visible light absorption,long excited state lifetime and efficient electron-hole separation of UiO-Ir-NBI greatly contributed to harvesting visible light and facilitating interface electron/energy transfer for efficient solar energy utilization.This work provides a new horizon to boost photosythesis of MOFs by engineering their metal sensitizing centers at a molecular level.

Optical and electrical properties of copper-incorporated ZnS films applicable as solar cell absorbers

Un-doped and Cu-doped ZnS（ZnS：Cu） thin films were synthesized by Successive Ion Layer Absorption and Reaction（SILAR） method. The UV–visible absorption studies have been used to calculate the band gap values of the fabricated ZnS：Cu thin films. It was observed that by increasing the concentration of Cu^2＋ ions, the Fermi level moves toward the edge of the valence band of ZnS. Photoluminescence spectra of un-doped and Cu-doped ZnS thin films was recorded under 355 nm. The emission spectrum of samples has a blue emission band at 436 nm.The peak positions of the luminescence showed a red shift as the Cu^2＋ C ion concentration was increased, which indicates that the acceptor level（of Cu^2＋） is getting close to the valence band of ZnS.

Nanoporous characteristics of sol-gel-derived ZnO thin film

Sol-gel-derived nanoporous ZnO film has been successfully deposited on glass substrate at 200 °C and subsequently annealed at different temperatures of 300, 400 and 600 °C. Atomic force micrographs demonstrated that the film was crack-free, and that granular nanoparticles were homogenously distributed on the film surface. The average grain size of the nanoparticles and RMS roughness of the scanned surface area was 10 nm and 13.6 nm, respectively, which is due to the high porosity of the film. Photoluminescence （PL） spectra of the nanoporous ZnO film at room temperature show a diffused band, which might be due to an increased amount of oxygen va- cancies on the lattice surface. The observed results of the nanoporous ZnO film indicates a promising application in the development of electrochemical biosensors due to the porosity of film enhancing the higher loading of biomacromolecules （enzyme and proteins）.

Optical and magnetic properties of perovskite materials:Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) and Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3)

Structural,optical and magnetic properties are reported for new synthesized perovskite materials.Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) and Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3) compositions were prepared via solid state reaction.X-ray analysis confirms that both compositions show feature of perovskite structure.Rietveld refinement method was used to confirm the phase formation and investigate the structure and space group.The study demonstrates the formation of orthorhombic structure with Pnma space group for Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) while the composition Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3) structure adopts Pbnm symmetry.UV–vis spectroscopy measurements show very broad and intense UV–visible light absorption,the estimated band gap ranges between 2.07 and 2.15 eV.Magnetic measurements were carried out for the compositions Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) and Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3).The hysteresis loops of both samples at 300 and 10 K show a strong ferromagnetic behavior.The temperature dependent magnetization at 0.05 T under field-cooled(FC)and zero field cooled(ZFC)modes shows magnetic frustration or spin glass-like behavior.

Synthesis and characterization of soluble intrinsic black polyimide with excellent comprehensive properties

Black polyimides(BPIs)have attracted increasing attention owing to their growing demand in optoelectronics.However,commonly used black polyimides doped with black fillers suffer from poor mechanical and electrical properties.To address these issues,a new diamine(2,5-bis(4′-amino-[1,1′-biphenyl]-4-yl)-3,4-bis(4-fluorophenyl)cyclopenta-2,4-dien-1-one,TPCPFPDA)bearing a tetraphenylcyclopentadienone(TPCP)moiety bonded with benzene and fluorine units was synthesized.The diamine was reacted with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)to yield a soluble intrinsic black polyimide(TPCPFPPI).Bonding fluorine(auxochrome group)and benzene units to TPCP can increase the conjugation ofπ-electrons systems and facilitate the movement of electron throughout the bigπbond,respectively.Owing to the structural features,the synthesized TPCPFPPI exhibited complete visible-light absorption with high blackness and opacity.Its cutoff wavelength(λ_(cut))and CIE(Commission Internationale de I′Eclairage)parameter L^(*)were 684 nm and 1.33,respectively.Moreover,TPCPFPPI displayed exceptional electrical,mechanical,and thermal properties as well as excellent solubility.A detailed theoretical calculation was conducted to gain better insight into the electronic properties of the TPCPFPPI.Results showed that the blackness of TPCPFPPI was chiefly attributed to the electron transition from highest occupied molecular orbital(HOMO)to lowest unoccupied molecular orbital(LUMO)in the diamines,where the charges primarily migrated from the aryl groups in the 2-and 5-positions to the cyclopentadienone center.The as-obtained intrinsic BPI(TPCPFPPI),exhibiting both high solubility and outstanding overall properties,has important applications in photo-electronics.

高光稳定性的全稠环分子在近红外安全和防伪中的应用

可见光与近红外(NIR)光的分离在近红外相关领域中有重要意义.选择性地从环境中提取近红外光的可见光不透明-近红外透明(VONIRT)材料在许多领域都有着广泛的应用.VONIRT材料通常是无机材料,通常存在脆性、毒性或者制备成本高的缺点.经典有机分子由于其吸收光谱不够宽,不能覆盖到全部可见光区域,不能作为VONIRT材料使用.在本工作中,我们报道了具有ADA’DA构型的全稠环分子,将其作为VONIRT材料应用于近红外安全与防伪中.通过对分子的分子内电荷转移进行调节,这类分子实现了400到800 nm的宽吸收光谱,半峰宽为299 nm.此外,由于它们的全稠环骨架,这些分子表现出优异的光稳定性.将优化后的全稠环分子与高分子基底共混,成功制备了VONIRT滤光片.该滤光片可以选择性地阻挡可见光以及透过近红外光.该滤光片不仅可以选择性提取环境中的近红外光,也能在近红外相关的实际场景(近红外安全、法医学以及防伪等)中使用.本工作揭示了全稠环分子的一种新的光学性质,并且提供了一类新型的、实用的VONIRT材料.