Exploration of novel organic luminophores that exhibit thermally activated delayed fluorescence(TADF) in the aggregated state is very crucial for advance of delayed luminescence-based applications such as time-gated b...Exploration of novel organic luminophores that exhibit thermally activated delayed fluorescence(TADF) in the aggregated state is very crucial for advance of delayed luminescence-based applications such as time-gated bio-sensing and temperature sensing.We report herein that synthesis, photophysical properties, molecular and crystal structures, and theoretical calculations of 2,6-bis(diarylamino)benzophenones. Absorption spectra in solution and calculations using density functional theory(DFT) method revealed that the optical excitation took place through intramolecular charge-transfer from one diarylamino moiety to an aroyl group. While the benzophenones did not luminesce in solution, the solids of the benzophenones emitted green light with moderate-to-good quantum yields. Thus, the benzophenones exhibit aggregation-induced emission. Based on the lifetime measurement, the green emission of the solids was found to include TADF. The emergence of the TADF is supported by the small energy gap between the excited singlet and triplet states, which was estimated by time-dependent DFT calculations. Thin films of poly(methyl methacrylate) doped by the benzophenones also showed green prompt and delayed fluorescence whose lifetimes were in the order of microseconds. Linear correlation between logarithm value of TADF lifetime and temperature was observed with the benzophenone in powder, suggesting that the benzophenones can serve as molecular thermometers workable under aqueous conditions.展开更多
In Quantum Information Theory(QIT) the classical measures of information content in probability distributions are replaced by the corresponding resultant entropic descriptors containing the nonclassical terms generate...In Quantum Information Theory(QIT) the classical measures of information content in probability distributions are replaced by the corresponding resultant entropic descriptors containing the nonclassical terms generated by the state phase or its gradient(electronic current). The classical Shannon(S[p]) and Fisher(I[p]) information terms probe the entropic content of incoherent local events of the particle localization, embodied in the probability distribution p, while their nonclassical phase-companions, S[ Φ ] and I[ Φ ], provide relevant coherence information supplements.Thermodynamic-like couplings between the entropic and energetic descriptors of molecular states are shown to be precluded by the principles of quantum mechanics. The maximum of resultant entropy determines the phase-equilibrium state, defined by "thermodynamic" phase related to electronic density,which can be used to describe reactants in hypothetical stages of a bimolecular chemical reaction.Information channels of molecular systems and their entropic bond indices are summarized, the complete-bridge propagations are examined, and sequential cascades involving the complete sets of the atomic-orbital intermediates are interpreted as Markov chains. The QIT description is applied to reactive systems R = A―B, composed of the Acidic(A) and Basic(B) reactants. The electronegativity equalization processes are investigated and implications of the concerted patterns of electronic flows in equilibrium states of the complementarily arranged substrates are investigated. Quantum communications between reactants are explored and the QIT descriptors of the A―B bond multiplicity/composition are extracted.展开更多
Exploring the discrete complexes with multi-step coloration is still a challenge in the field of electron transfer photochromic materials. Herein, we synthesized a series of dinuclear Ln-diphosphonate compounds[Ln=Dy(...Exploring the discrete complexes with multi-step coloration is still a challenge in the field of electron transfer photochromic materials. Herein, we synthesized a series of dinuclear Ln-diphosphonate compounds[Ln=Dy(1);Gd(2);Tb(3);Y(4)] with a remarkably and reversibly photoactive coloration phenomenon. These compounds showed two-step coloration behavior, which were the first discrete architectures in the reported electron transfer photochromic complexes. This two-step coloration phenomenon was originated from the large distortion of H3-TPT acceptors, which in turn reduced the π-conjugation of electron acceptors and slowed the decay process of electron transfer. The photogenerated stable doublet radicals originated from electron transfer from diphosphonate donor to polypyridine acceptor in these complexes were detected by UV-Vis and electron spin resonance(ESR) spectra. Furthermore, the photogenerated radicals were estimated by direct current magnetic susceptibilities and variable temperature ESR spectra, suggesting the doublet radicals in the dinuclear structure for all the compounds. This work revealed a series of discrete phosphonate-based systems with a multi-step coloration process, providing a new pathway for designing multicolor photochromic materials with potential photoswitching or other applications.展开更多
Small-molecule organic solar cell is a category of clean energy potential device since charge transfers between donor and acceptor.The morphologies,co-assembly behavior,interaction sites,and charge transfer of BTID-nF...Small-molecule organic solar cell is a category of clean energy potential device since charge transfers between donor and acceptor.The morphologies,co-assembly behavior,interaction sites,and charge transfer of BTID-nF(n=1,2)/PC71BM donor-acceptor system in the active layer of organic solar cell have been studied employing scanning tunneling microscopy(STM),scanning tunneling spectroscopy(STS),density functional theory(DFT)calculations,and transient absorption(TA)spectroscopy.The results show that BTID-1F and BTID-2F form bright strip structures,whereas BTID-nF(n=1,2)/PC71BM form ridge-like structures with each complex composed of one BTID-nF(n=1,2)molecule and four PC71BM molecules which adsorbed around the BTID-nF(n=1,2)molecule by S···πinteraction.With the assistance of S···πinteraction between BTID-nF(n=1,2)and PC71BM,BTID-nF(n=1,2)/PC71BM co-assembled ridge-like structures are more stable than the BTID-nF(n=1,2)ridge structures.To investigate the charge transfer of BTID-nF(n=1,2)/PC71BM system,STS measurements,DFT calculation,and TA spectroscopy are further performed.The results show that charge transfer occurs in BTID-nF(n=1,2)/PC71BM system with the electron transferring from BTID-nF(n=1,2)molecules to PC71BM.展开更多
基金supported by Grants-in-Aid for JSPS KAKENHI (15H03795)MEXT KAKENHI 15K13671+1 种基金the Nagase Science and Technology Foundationthe Ogasawara Foundation for the Promotion of Science and Engineering
文摘Exploration of novel organic luminophores that exhibit thermally activated delayed fluorescence(TADF) in the aggregated state is very crucial for advance of delayed luminescence-based applications such as time-gated bio-sensing and temperature sensing.We report herein that synthesis, photophysical properties, molecular and crystal structures, and theoretical calculations of 2,6-bis(diarylamino)benzophenones. Absorption spectra in solution and calculations using density functional theory(DFT) method revealed that the optical excitation took place through intramolecular charge-transfer from one diarylamino moiety to an aroyl group. While the benzophenones did not luminesce in solution, the solids of the benzophenones emitted green light with moderate-to-good quantum yields. Thus, the benzophenones exhibit aggregation-induced emission. Based on the lifetime measurement, the green emission of the solids was found to include TADF. The emergence of the TADF is supported by the small energy gap between the excited singlet and triplet states, which was estimated by time-dependent DFT calculations. Thin films of poly(methyl methacrylate) doped by the benzophenones also showed green prompt and delayed fluorescence whose lifetimes were in the order of microseconds. Linear correlation between logarithm value of TADF lifetime and temperature was observed with the benzophenone in powder, suggesting that the benzophenones can serve as molecular thermometers workable under aqueous conditions.
文摘In Quantum Information Theory(QIT) the classical measures of information content in probability distributions are replaced by the corresponding resultant entropic descriptors containing the nonclassical terms generated by the state phase or its gradient(electronic current). The classical Shannon(S[p]) and Fisher(I[p]) information terms probe the entropic content of incoherent local events of the particle localization, embodied in the probability distribution p, while their nonclassical phase-companions, S[ Φ ] and I[ Φ ], provide relevant coherence information supplements.Thermodynamic-like couplings between the entropic and energetic descriptors of molecular states are shown to be precluded by the principles of quantum mechanics. The maximum of resultant entropy determines the phase-equilibrium state, defined by "thermodynamic" phase related to electronic density,which can be used to describe reactants in hypothetical stages of a bimolecular chemical reaction.Information channels of molecular systems and their entropic bond indices are summarized, the complete-bridge propagations are examined, and sequential cascades involving the complete sets of the atomic-orbital intermediates are interpreted as Markov chains. The QIT description is applied to reactive systems R = A―B, composed of the Acidic(A) and Basic(B) reactants. The electronegativity equalization processes are investigated and implications of the concerted patterns of electronic flows in equilibrium states of the complementarily arranged substrates are investigated. Quantum communications between reactants are explored and the QIT descriptors of the A―B bond multiplicity/composition are extracted.
基金This work was supported by the National Natural Science Foundation of China(Nos.21901133,91856124,22035003,91961114,21871039)China National Postdoctoral Program for Innovative Talents(No.BX20180147).
文摘Exploring the discrete complexes with multi-step coloration is still a challenge in the field of electron transfer photochromic materials. Herein, we synthesized a series of dinuclear Ln-diphosphonate compounds[Ln=Dy(1);Gd(2);Tb(3);Y(4)] with a remarkably and reversibly photoactive coloration phenomenon. These compounds showed two-step coloration behavior, which were the first discrete architectures in the reported electron transfer photochromic complexes. This two-step coloration phenomenon was originated from the large distortion of H3-TPT acceptors, which in turn reduced the π-conjugation of electron acceptors and slowed the decay process of electron transfer. The photogenerated stable doublet radicals originated from electron transfer from diphosphonate donor to polypyridine acceptor in these complexes were detected by UV-Vis and electron spin resonance(ESR) spectra. Furthermore, the photogenerated radicals were estimated by direct current magnetic susceptibilities and variable temperature ESR spectra, suggesting the doublet radicals in the dinuclear structure for all the compounds. This work revealed a series of discrete phosphonate-based systems with a multi-step coloration process, providing a new pathway for designing multicolor photochromic materials with potential photoswitching or other applications.
基金the National Basic Research Program of China(Nos.2017YFA0205000 and 2016YFA0200700)the National Natural Science Foundation of China(Nos.21773041,21972031,21301092,and 20962002)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000).
文摘Small-molecule organic solar cell is a category of clean energy potential device since charge transfers between donor and acceptor.The morphologies,co-assembly behavior,interaction sites,and charge transfer of BTID-nF(n=1,2)/PC71BM donor-acceptor system in the active layer of organic solar cell have been studied employing scanning tunneling microscopy(STM),scanning tunneling spectroscopy(STS),density functional theory(DFT)calculations,and transient absorption(TA)spectroscopy.The results show that BTID-1F and BTID-2F form bright strip structures,whereas BTID-nF(n=1,2)/PC71BM form ridge-like structures with each complex composed of one BTID-nF(n=1,2)molecule and four PC71BM molecules which adsorbed around the BTID-nF(n=1,2)molecule by S···πinteraction.With the assistance of S···πinteraction between BTID-nF(n=1,2)and PC71BM,BTID-nF(n=1,2)/PC71BM co-assembled ridge-like structures are more stable than the BTID-nF(n=1,2)ridge structures.To investigate the charge transfer of BTID-nF(n=1,2)/PC71BM system,STS measurements,DFT calculation,and TA spectroscopy are further performed.The results show that charge transfer occurs in BTID-nF(n=1,2)/PC71BM system with the electron transferring from BTID-nF(n=1,2)molecules to PC71BM.
