Thermally activated delayed fluorescence(TADF)molecules have attracted great attention as high efficient luminescent materials.Most of TADF molecules possess small energy gap between the first singlet excited state(S_...Thermally activated delayed fluorescence(TADF)molecules have attracted great attention as high efficient luminescent materials.Most of TADF molecules possess small energy gap between the first singlet excited state(S_(1))and the first triplet excited state(T_(1))to favor the up-conversion from T_(1)to S_(1).In this paper,a new TADF generation mechanism is revealed based on theoretical simulation.By systematic study of the light-emitting properties of SOBF-OMe in both toluene and in aggregation state,we find that the single SOBF-OMe could not realize TADF emission due to large energy gap as well as small up-conversion rates between S_(1)and T_(1).Through analysis of dimers,we find that dimers with intermolecular hydrogen bond(H-bond)are responsible for the generation of TADF,since smaller energy gap between S_(1)and T_(1)is found and the emission wavelength is in good agreement with experimental counterpart.The emission properties of SOBF-H are also studied for comparison,which reflect the important role of H-bond.Our theoretical results agree ith experimental results well and confirm the mechanism of H-bond induced TADF.展开更多
This paper reports that vibrational spectroscopic analysis on hYdrogen-bonding between acetone and water comprises both experimental Raman spectra and ab initio calculations on structures of various acetone/water comp...This paper reports that vibrational spectroscopic analysis on hYdrogen-bonding between acetone and water comprises both experimental Raman spectra and ab initio calculations on structures of various acetone/water complexes with changing water concentrations. The optimised geometries and wavenumbers of the neat acetone molecule and its complexes are calculated by using ab initio method at the MP2 level with 6-311＋G（d,p） basis set. Changes in wavenumber position and linewidth （fullwidth at half maximum） have been explained for neat as well as binary mixtures with different mole fractions of the reference system, acetone, in terms of intermolecular hydrogen bonding. The combination of experimental Raman data with ab initio calculation leads to a better knowledge of the concentration dependent changes in the spectral features in terms of hydrogen bonding.展开更多
In this work, a novel long-wavelength fluorescence probe, 3-(4-chloro-6-methylamino-1,3,5-triazinylamino)-7-dimethylamino-2-methylphenazine, was synthesized by the reaction of neutral red and methylamine subsequently ...In this work, a novel long-wavelength fluorescence probe, 3-(4-chloro-6-methylamino-1,3,5-triazinylamino)-7-dimethylamino-2-methylphenazine, was synthesized by the reaction of neutral red and methylamine subsequently with cyanuric chloride, and its recognition behavior for thymine together with its spectroscopic properties in different solvents was studied. The results show that the fluorescence probe can be selectively quenched by thymine instead of guanine, suggesting that the fully complementary hydrogen bonding plays a key role in such a recognition process.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974216,11874242,21933002,and 11904210)the Natural Science Foundation of Shandong Province,China(Grant No.ZR2019MA056)+1 种基金the Taishan Scholar Project of Shandong Province,Chinathe Project funded by China Postdoctoral Science Foundation(Grant No.2018M642689)。
文摘Thermally activated delayed fluorescence(TADF)molecules have attracted great attention as high efficient luminescent materials.Most of TADF molecules possess small energy gap between the first singlet excited state(S_(1))and the first triplet excited state(T_(1))to favor the up-conversion from T_(1)to S_(1).In this paper,a new TADF generation mechanism is revealed based on theoretical simulation.By systematic study of the light-emitting properties of SOBF-OMe in both toluene and in aggregation state,we find that the single SOBF-OMe could not realize TADF emission due to large energy gap as well as small up-conversion rates between S_(1)and T_(1).Through analysis of dimers,we find that dimers with intermolecular hydrogen bond(H-bond)are responsible for the generation of TADF,since smaller energy gap between S_(1)and T_(1)is found and the emission wavelength is in good agreement with experimental counterpart.The emission properties of SOBF-H are also studied for comparison,which reflect the important role of H-bond.Our theoretical results agree ith experimental results well and confirm the mechanism of H-bond induced TADF.
基金supported by National Natural Science Foundation of China (Grant Nos.10774057 and 10974067)
文摘This paper reports that vibrational spectroscopic analysis on hYdrogen-bonding between acetone and water comprises both experimental Raman spectra and ab initio calculations on structures of various acetone/water complexes with changing water concentrations. The optimised geometries and wavenumbers of the neat acetone molecule and its complexes are calculated by using ab initio method at the MP2 level with 6-311＋G（d,p） basis set. Changes in wavenumber position and linewidth （fullwidth at half maximum） have been explained for neat as well as binary mixtures with different mole fractions of the reference system, acetone, in terms of intermolecular hydrogen bonding. The combination of experimental Raman data with ab initio calculation leads to a better knowledge of the concentration dependent changes in the spectral features in terms of hydrogen bonding.
文摘In this work, a novel long-wavelength fluorescence probe, 3-(4-chloro-6-methylamino-1,3,5-triazinylamino)-7-dimethylamino-2-methylphenazine, was synthesized by the reaction of neutral red and methylamine subsequently with cyanuric chloride, and its recognition behavior for thymine together with its spectroscopic properties in different solvents was studied. The results show that the fluorescence probe can be selectively quenched by thymine instead of guanine, suggesting that the fully complementary hydrogen bonding plays a key role in such a recognition process.
