scholarly journals FLUORESCENCE AND RED SHIFT OF THE PHOTOPHYSICAL PROPERTIES FROM PROTONATED SMALL MOLECULE

2020 ◽  
Vol 5 (1) ◽  
pp. 25-29
Author(s):  
Zakarias Seba Ngara
Keyword(s):  
Absorption Spectrum ◽  
Small Molecule ◽  
Energy Gap ◽  
Photophysical Properties ◽  
Photonic Devices ◽  
Red Shift ◽  
Direct Excitation ◽  
Develop Sensor ◽  
Color Emission ◽  
Film State

In this work, the fluorescence (FL) and bathochromic of the photophysical properties from protonated small molecule in cast film state have been investigated. To realize these purposes, the material of 4’,4’’’’-(1,4-phenylene bis (2,2’:6’,2”-terpyridine) (Phtpy) as a small molecule and  camphorsulfonic acid (CSA) as an acid for protonation was selected. For Phtpy, its maxima absorption is 300 nm and no FL color emission. After CSA solution was added in chlorofom solution of Phtpy, the absorption spectrum of protonated Phtpy is broaden to longer wavelength with two new peaks appear at around 350 and 370 nm. Upon direct excitation at wavelength of 300 nm, the range of FL spectrum of original and protonated Phtpy is from 320 to 580 nm and from 370 to 580 with their maxima FL intensities at 360 and 460 nm. Interestingly, protonated Phtpy emits blue FL color emission. In addition, energy gap of protonated Phtpy is smaller than that of pristine Phtpy. Finally, the FL  and remarkable red shift of absorption and FL spectra of protonated Phtpy will pave the way to develop sensor and other photonic devices with high performances in the ultaviolet region.

scholarly journals Exciton Coupling and Conformational Changes Impacting the Excited State Properties of Metal Organic Frameworks

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4230
Author(s):  
Andreas Windischbacher ◽  
Luca Steiner ◽  
Ritesh Haldar ◽  
Christof Wöll ◽  
Egbert Zojer ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Photophysical Properties ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Red Shift ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Exciton Coupling ◽  
Metal Organic ◽  
Crystalline Metal

In recent years, the photophysical properties of crystalline metal-organic frameworks (MOFs) have become increasingly relevant for their potential application in light-emitting devices, photovoltaics, nonlinear optics and sensing. The availability of high-quality experimental data for such systems makes them ideally suited for a validation of quantum mechanical simulations, aiming at an in-depth atomistic understanding of photophysical phenomena. Here we present a computational DFT study of the absorption and emission characteristics of a Zn-based surface-anchored metal-organic framework (Zn-SURMOF-2) containing anthracenedibenzoic acid (ADB) as linker. Combining band-structure and cluster-based simulations on ADB chromophores in various conformations and aggregation states, we are able to provide a detailed explanation of the experimentally observed photophysical properties of Zn-ADB SURMOF-2: The unexpected (weak) red-shift of the absorption maxima upon incorporating ADB chromophores into SURMOF-2 can be explained by a combination of excitonic coupling effects with conformational changes of the chromophores already in their ground state. As far as the unusually large red-shift of the emission of Zn-ADB SURMOF-2 is concerned, based on our simulations, we attribute it to a modification of the exciton coupling compared to conventional H-aggregates, which results from a relative slip of the centers of neighboring chromophores upon incorporation in Zn-ADB SURMOF-2.

An A–D–A′–D–A type small molecule acceptor with wide absorption spectrum and near-infrared absorption

2018 ◽  
Vol 2 (12) ◽  
pp. 2333-2339 ◽  
Author(s):  
Junhui Miao ◽  
Junxia Wang ◽  
Bin Meng ◽  
Jun Liu ◽  
Lixiang Wang
Keyword(s):  
Absorption Spectrum ◽  
Small Molecule ◽  
Infrared Absorption ◽  
Near Infrared

We report a new A–D–A′–D–A type small molecule acceptor with a wide absorption spectrum spanning from 300 nm to 900 nm and a bandgap of only 1.39 eV.

Tuning the Photophysical Properties of Cyclometalated Ir(III) Complexes by a Trifluoroacetyl Group

2012 ◽  
Vol 67 (3) ◽  
pp. 213-218 ◽  
Author(s):  
Bihai Tong ◽  
Jiayan Qiang ◽  
Qunbo Mei ◽  
Hengshan Wang ◽  
Qianfeng Zhang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Electron Acceptor ◽  
Photophysical Properties ◽  
Red Shift ◽  
Luminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Absorption And Luminescence Spectra ◽  
Homo Lumo

Four cationic Ir(III) complexes, [Ir(dpq)2(bpy)]PF6 (1), [Ir(dpq)2(phen)]PF6 (2), [Ir(tfapq)2- (bpy)]PF6 (3), and [Ir(tfapq)2(phen)]PF6 (4) (dpqH = 2,4-diphenylquinoline, tfapqH = 2-(4ʹ-trifluoroacetylphenyl)- 4-phenylquinoline, bpy = 2,2ʹ-bipyridine, phen = 1,10-phenanthroline) have been synthesized and fully characterized. The structure of 4 was also confirmed by single-crystal X-ray diffraction. The electron-acceptor character of the trifluoroacetyl unit leads to a reduced HOMO-LUMO gap and consequently a red-shift of the UV/Vis absorption and luminescence spectra. The solvophobic character of the trifluoroacetyl unit gives rise to a molecule assembly in solution.

Improved performances of PCDTBT:PC71BM BHJ solar cells through incorporating small molecule donor

2015 ◽  
Vol 17 (40) ◽  
pp. 26777-26782 ◽  
Author(s):  
Youqin Zhu ◽  
Lin Yang ◽  
Suling Zhao ◽  
Yan Huang ◽  
Zheng Xu ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Solar Cells ◽  
Energy Loss ◽  
Small Molecule

Incorporating SQ-BP into a PCDTBT:PC71BM host blend not only broadens the absorption spectrum but also decreases the energy loss of excited PCDTBT.

Unusual spectral shifts in the prototropic reactions of 2,7-diaminofluorene

1987 ◽  
Vol 65 (9) ◽  
pp. 2013-2018 ◽  
Author(s):  
R. Manoharan ◽  
Sneh K. Dogra
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Medium ◽  
Fluorescence Spectrum ◽  
Blue Shift ◽  
Proton Donor ◽  
Red Shift ◽  
The Other ◽  
Spectral Shifts ◽  
Other Hand

The red shift observed in the absorption spectrum of 2,7-diaminofluorene (DAF) in ether and acetonitrile is either due to the proton-donating capacity of the solute or due to its dispersive interactions with the solvent and a blue shift in methanol and water is due to the proton-accepting nature of DAF. DAF acts as a proton donor in S1 state in all solvents. The red shift in the fluorescence spectrum of the monocation of DAF relative to that of DAF is not because of the —NH2 group becoming more basic but because of the large solvent relaxating in aqueous medium. On the other hand, the monocation of DAF in cyclohexane follows the normal blue shift in the fluorescence spectrum. pKa values for the various prototropic reactions in S0 and S1 states are determined and discussed.

Nanoscale aggregates of porphyrin: red-shifted absorption, enhanced absorbance and phototherapeutic activity

2021 ◽  
Author(s):  
Qihang Wu ◽  
Rui Xia ◽  
Chaonan Li ◽  
Yite Li ◽  
Tingting Sun ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Photophysical Properties ◽  
Nanoscale Aggregates ◽  
Supramolecular Aggregation

Supramolecular aggregation of fluorophores will result in a variable absorption spectrum, which is beneficial for tunning the photophysical properties and improving their functionalities. Herein, ordered aggregates of liposoluble porphyrin molecules...

scholarly journals Tuning the near infrared II emitting wavelength of small molecule dyes by single atom alteration

2020 ◽  
Vol 56 (4) ◽  
pp. 523-526 ◽  
Author(s):  
Kun Qian ◽  
Chunrong Qu ◽  
Xiangyu Ma ◽  
Hao Chen ◽  
Martha Kandawa-Schulz ◽  
...  
Keyword(s):  
Small Molecule ◽  
Near Infrared ◽  
Fluorescence Emission ◽  
Red Shift ◽  
Single Atom

Replacing donors’ S with O and Se will red shift NIR-II dyes’ fluorescence emission and offer good clarity/brightness for imaging.

Synthesis and Photophysical Properties of Side-Chain Polyfluorenes

2017 ◽  
Vol 865 ◽  
pp. 60-63
Author(s):  
Ning Wang ◽  
Xiao Dan Hu
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Photophysical Properties ◽  
Gel Permeation Chromatography ◽  
Blue Shift ◽  
Red Shift ◽  
Side Chain ◽  
Gel Permeation

In this paper, we reported one vinylfluorene derivative 9,9-dihexyl-vinylfluorene and its corresponding polymers. The monomer and polymers were characterized by NMR, UV-Vis, PL and Gel Permeation Chromatography (GPC). Compared with the monomer, the polymers showed blue-shift in UV-Vis spectra but red-shift in PL spedtra. This kind of side-chain polyfluorenes could be candidates of blue OLED, organic solar cells, and so on.

Synthesis and Photophysical Study of Divalent Complexes of Chelating Schiff Base

2020 ◽  
Vol 1 (01) ◽  
pp. 5-16
Author(s):  
Alaa A. Rashad ◽  
Farah Muaiad ◽  
Ahmed Ahmed ◽  
EkhlasA. Salman ◽  
Evon Akram
Keyword(s):  
Schiff Base ◽  
Surface Morphology ◽  
Theoretical Study ◽  
Energy Gap ◽  
Photophysical Properties ◽  
Schiff Base Complex ◽  
Tetrahedral Geometry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Square Planar

 Background: Schiff base compounds derivative from1,2,4-triazole, and their transition metal complexes play an essential role in coordination and bioinorganic chemistry due to biological and industrial applications. Objective: The work aims to prepare and characterize of 1, 2, 4-triazole Schiff base and its complexes with a theoretical study using  PM3 calculation and HyperChem program, photophysical properties, and surface morphology for these complexes. Methods: 1, 2, 4-triazole Schiff base prepared by condensation reaction between  4-Amino-3-mercapto-5-phenyl-4H-1,2,4-triazole and 2-hydroxy-1-naphthaldehyde, then Schiff base reacted with Co2+, Ni2+,  and Cu2+ ions,   the synthesized 1, 2, 4-triazole Schiff base, and its complexes were characterized by infrared spectra, magnetic susceptibility, conductivity measurements, photophysical properties, and surface morphology measured by atomic force microscopy. The practical results were reinforced with a theoretical study for these Schiff base complexes. Then the proposed structures of the prepared complexes. Results: 1, 2, 4-triazole Schiff base act as a chelate ligand. The coordination has occurred through the oxygen of the phenolic group O-H and the nitrogen of the imine group N=C of Schiff base with divalent metal ions. Cobalt complex has a tetrahedral geometry, while the nickel and copper complexes have square planar geometries. The stability of all compounds was studied by calculating the energy gap by diffuse reflectance spectroscopy and theoretical calculations. Copper Schiff base is a more stable complex due to the lower value of the energy gap, and the copper Schiff base complex is more semiconductivity than the other complexes. Surface morphology, properties of chelating  Schiff base ligand and its complexes measured by atomic force microscopy, cobalt Schiff base complex is higher roughness. The bond length of (-C=N-), (-C-O-),(M-O), and (M-N)  are affected in the coordination with metal ions, the bond length of the square planar geometry more affected than tetrahedral geometry. Conclusion: All compounds were prepared successfully, characterized, and photophysical properties were studied.  

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