共查询到20条相似文献,搜索用时 15 毫秒
1.
Lili Huang Lei Liu Xianjiang Li Huan Hu Mingxing Chen Qingyuan Yang Zhiyong Ma Xinru Jia 《Angewandte Chemie (International ed. in English)》2019,58(46):16445-16450
A D‐A‐D′ type pure organic molecule, named ODFRCZ, has unique triple‐emission character covering fluorescence, phosphorescence, and delayed fluorescence (DF). The phosphorescence of ODFRCZ has a rather long lifetime of about 350 ms at room temperature. One dimer of ODFRCZ with enhanced parallel molecular packing acts more effectively to prompt ISC processes, which further generates room‐temperature phosphorescence (RTP), owing to the larger transition dipole moment and closer energy level between S1 and Tn. ODFRCZ is a rare example of an organic RTP molecule that shows dual‐stimuli responsiveness of dual‐mode mechanochromism (fluorescence red‐shift and RTP/DF on‐off switch) and reversible crystal‐state photochromism. This work may broaden the knowledge for stimuli‐responsive RTP organic molecules and lay the foundation for their wide‐scale applications. 相似文献
2.
Guangxi Huang Qing Xia Wenbin Huang Jianwu Tian Zikai He Bing Shi Li Ben Zhong Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(49):17978-17983
Herein the novel tetraphenylethylene (TPE) derivative 1 was designed with an integration of aggregation‐induced emission (AIE), multi‐state mechanochromism and self‐recovery photochromism. The molecule was susceptible to grinding, heating and vapor fuming and showed corresponding transition of its emission colors. The heated powder or single crystal of 1 exhibited reversible photochromism. After a short period of UV irradiation, it showed a bright red color, but recovered to its original white appearance within 1 min. The photochromism is due to the formation of photocyclization intermediates upon UV irradiation, while the eversible mechanochromism is attributed to the weak molecular interactions derived from head‐to‐tail stacking of the molecules. This reversible multi‐state, high‐contrasted and rapid responsive mechanochromic and photochromic property cooperatively provide double enhancement of a multimode guarantee in advanced anti‐counterfeiting. 相似文献
3.
Wei Xu Yaguo Yu Xiaonan Ji Huarui Zhao Jinming Chen Yanyan Fu Huimin Cao Qingguo He Jiangong Cheng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(45):16164-16168
The stability of pure organic room‐temperature phosphorescent (RTP) materials in air has been a research hotspot in recent years. Without crystallization or encapsulation, a new strategy was proposed to obtain self‐stabilized organic RTP materials, based on a complete ionization of a photo‐induced charge separation system. The ionization of aromatic phenol 4‐carbazolyl salicylaldehyde (CSA) formed a stable H‐bonding anion–cation radical structure and led to the completely amorphous CSA‐I film. Phosphorescent lifetimes as long as 0.14 s at room temperature and with direct exposure to air were observed. The emission intensity was also increased by 21.5‐fold. Such an amorphous RTP material reconciled the contradiction between phosphorescence stability and vapor permeability and has been successfully utilized for peroxide vapor detection. 相似文献
4.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(40):12328-12332
Persistent room‐temperature phosphorescence (RTP) in pure organic materials has attracted great attention because of their unique optical properties. The design of organic materials with bright red persistent RTP remains challenging. Herein, we report a new design strategy for realizing high brightness and long lifetime of red‐emissive RTP molecules, which is based on introducing an alkoxy spacer between the hybrid units in the molecule. The spacer offers easy Br−H bond formation during crystallization, which also facilitates intermolecular electron coupling to favor persistent RTP. As the majority of RTP compounds have to be confined in a rigid environment to quench nonradiative relaxation pathways for bright phosphorescence emission, nanocrystallization is used to not only rigidify the molecules but also offer the desirable size and water‐dispersity for biomedical applications. 相似文献
5.
Cristian A. M. Salla Giliandro Farias Mathieu Rouzires Pierre Dechambenoit Fabien Durola Harald Bock Bernardo deSouza Ivan H. Bechtold 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(21):7056-7060
The dehydrating cyclotrimerization of 1‐tetralone in the presence of titanium tetrachloride at high temperatures leads to homotruxene, a nonplanar arene in which the twist angles between its three outer benzene rings and the central benzene are stabilized by ethylene bridges. This non‐planar configuration allows for pronounced spin–orbit coupling and a high triplet energy, leading to room‐temperature phosphorescence in air with a lifetime of 0.38 s and a quantum yield of 5.6 %, clearly visible to the human eye after switching off the excitation. Triplet–triplet annihilation is found to simultaneously lead to a substantial delayed fluorescence, unprecedented from a pure hydrocarbon at ambient conditions, with a lifetime of 0.11 s. 相似文献
6.
Jinfeng Wang Zhaofei Chai Jiaqiang Wang Can Wang Mengmeng Han Qiuyan Liao Arui Huang Peixuan Lin Conggang Li Qianqian Li Zhen Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(48):17457-17462
Mechanoluminescence (ML) and room‐temperature photophosphorescence (RTP) were achieved in polymorphisms of a triphenylamine derivative with ortho‐substitution. This molecular packing‐dependent emission afforded crucial information to deeply understand the intrinsic mechanism of different emission forms and the possible packing–function relationship. With the incorporation of solid‐state 13C NMR spectra of single crystals, as well as the analysis of crystal structures, the preferred packing modes for ML and/or RTP were investigated in detail, which can guide the reasonable design of organic molecules with special light‐emission properties. 相似文献
7.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(17):4950-4954
The photophysical properties of a Keggin‐type polyoxometalate (POM) covalently bounded to a benzospiropyran (BSPR) unit have been investigated. These studies reveal that both closed and open forms are emissive with distinct spectral features (λ em (closed form)=530 nm, λ em (open form)=670 nm) and that the fluorescence of the BSPR unit of the hybrid is considerably enhanced compared to BSPR parent compounds. While the fluorescence excitation energy of the BSPR reference compounds (370 nm) is close to the intense absorption responsible of the photochromic character (350 nm), the fluorescence excitation of the hybrid is shifted to lower energy (400 nm), improving the population of the emissive state. Combined NOESY NMR and theoretical calculations of the closed form of the hybrid give an intimate understanding of the conformation adopted by the hybrid and show that the nitroaryl moieties of the BSPR is folded toward the POM, which should affect the electronic properties of the BSPR. 相似文献
8.
Bolun Wang Yue Yu Hongyue Zhang Yuzhi Xuan Guangrui Chen Wenyan Ma Jiyang Li Jihong Yu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(51):18614-18619
High‐efficiency red room‐temperature phosphorescence (RTP) emissions have been achieved by embedding carbon dots (CDs) in crystalline Mn‐containing open‐framework matrices. The rationale of this strategy relies on two factors: 1) the carbon source, which affects the triplet energy levels of the resulting CDs and thus the spectral overlap and 2) the coordination geometry of the Mn atoms in the crystalline frameworks, which determines the crystal‐field splitting and thus the emission spectra. Embedding the carbon dots into a matrix with 6‐coordinate Mn centers resulted in a strong red RTP with a phosphorescence efficiency of up to 9.6 %, which is higher than that of most reported red RTP materials. The composite material has an ultrahigh optical stability in the presence of strong oxidants, various organic solvents, and strong ultraviolet radiation. A green‐yellow RTP composite was also prepared by using a matrix with 4‐coordinate Mn centers and different carbon precursors. 相似文献
9.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(48):15501-15505
Two stable, purely organic luminogens exhibit both mechano‐ (ML) and photoluminescence (PL) with dual fluorescence–phosphorescence emissions at room temperature. Careful analysis of the crystal structures, coupled with theoretical calculations, demonstrate that room‐temperature phosphorescence and ML properties are strongly related to molecular packing. In particular, the formation and fracture of molecular dimers with intermolecular charge‐transfer properties has a significant effect on intersystem crossing, as well as excited triplet state emissions, in both PL and ML processes. 相似文献
10.
11.
Kai Jiang Xiaolu Gao Xiangyu Feng Yuhui Wang Zhongjun Li Hengwei Lin 《Angewandte Chemie (International ed. in English)》2020,59(3):1263-1269
Carbon dots (CDs) with dual‐emissive, robust, and aggregation‐induced RTP characteristics are reported for the first time. The TA‐CDs are prepared via hydrothermal treatment of trimellitic acid and exhibit unique white prompt and yellow RTP emissions in solid state under UV excitation (365 nm) on and off, respectively. The yellow RTP emission of TA‐CDs powder should be resulted from the formation of a new excited triplet state due to their aggregation, and the white prompt emission is due to their blue fluorescence and yellow RTP dual‐emissive nature. The RTP emission of TA‐CDs powder was highly stable under grinding, which is very rare amongst traditional pure organic RTP materials. To employ the unique characteristics of TA‐CDs, advanced anti‐counterfeiting and information encryption methodologies (water‐stimuli‐response producing RTP) were preliminarily investigated. 相似文献
12.
Xiao Liang Ting‐Ting Liu Zhi‐Ping Yan Yan Zhou Jian Su Xu‐Feng Luo Zheng‐Guang Wu Yi Wang You‐Xuan Zheng Jing‐Lin Zuo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(48):17380-17385
Pure organic materials with intrinsic room‐temperature phosphorescence typically rely on heavy atoms or heteroatoms. Two different strategies towards constructing organic room‐temperature phosphorescence (RTP) species based upon the through‐space charge transfer (TSCT) unit of [2.2]paracyclophane (PCP) were demonstrated. Materials with bromine atoms, PCP‐BrCz and PPCP‐BrCz, exhibit RTP lifetime of around 100 ms. Modulating the PCP core with non‐halogen‐containing electron‐withdrawing units, PCP‐TNTCz and PCP‐PyCNCz, successfully elongate the RTP lifetime to 313.59 and 528.00 ms, respectively, the afterglow of which is visible for several seconds under ambient conditions. The PCP‐TNTCz and PCP‐PyCNCz enantiomers display excellent circular polarized luminescence with dissymmetry factors as high as ?1.2×10?2 in toluene solutions, and decent RTP lifetime of around 300 ms for PCP‐TNTCz enantiomers in crystalline state. 相似文献
13.
Pure organic luminogens with persistent room‐temperature phosphorescence (p‐RTP) have attracted increasing attention owing to their vital significance and potential applications in security inks, bioimaging, and photodynamic therapy. Previously reported p‐RTP luminogens normally possessed through‐bond conjugation. In this work, we report a pure organic luminogen, AN‐MA, the Diels–Alder cycloaddition adduct of anthracene (AN) and maleic anhydride (MA), which possesses isolated phenyl groups and an anhydride moiety. AN‐MA exhibits aggregation‐enhanced emission (AEE) characteristics with efficiency of approximately 2 % and up to 8.5 % in solution and crystals, respectively. Two polymorphs of AN‐MA were readily obtained that were able to generate UV emission from individual phenyl rings together with bright blue emission owing to the effective through‐space conjugation. Moreover, p‐RTP with a lifetime of up to approximately 1.6 s was obtained in the crystals. These results not only reveal a new system with both fluorescence and RTP dual emission but also suggest an alternative through‐space conjugation strategy towards pure organic p‐RTP luminogens with tunable emissions. 相似文献
14.
15.
Intermolecular Electronic Coupling of Organic Units for Efficient Persistent Room‐Temperature Phosphorescence 下载免费PDF全文
Dr. Zhiyong Yang Dr. Zhu Mao Dr. Xuepeng Zhang Dr. Depei Ou Dr. Yingxiao Mu Prof. Yi Zhang Prof. Cunyuan Zhao Prof. Siwei Liu Prof. Zhenguo Chi Prof. Jiarui Xu Dr. Yuan‐Chun Wu Dr. Po‐Yen Lu Dr. Alan Lien Prof. Martin R. Bryce 《Angewandte Chemie (International ed. in English)》2016,55(6):2181-2185
Although persistent room‐temperature phosphorescence (RTP) emission has been observed for a few pure crystalline organic molecules, there is no consistent mechanism and no universal design strategy for organic persistent RTP (pRTP) materials. A new mechanism for pRTP is presented, based on combining the advantages of different excited‐state configurations in coupled intermolecular units, which may be applicable to a wide range of organic molecules. By following this mechanism, we have developed a successful design strategy to obtain bright pRTP by utilizing a heavy halogen atom to further increase the intersystem crossing rate of the coupled units. RTP with a remarkably long lifetime of 0.28 s and a very high quantum efficiency of 5 % was thus obtained under ambient conditions. This strategy represents an important step in the understanding of organic pRTP emission. 相似文献
16.
Ren A. Wiscons Dr. N. Rajesh Goud Dr. Joshua T. Damron Prof. Adam J. Matzger 《Angewandte Chemie (International ed. in English)》2018,57(29):9044-9047
Ferroelectric materials exhibit switchable remanent polarization due to reversible symmetry breaking under an applied electric field. Previous research has leveraged temperature‐induced neutral‐ionic transitions in charge‐transfer (CT) cocrystals to access ferroelectrics that operate through displacement of molecules under an applied field. However, displacive ferroelectric behavior is rare in organic CT cocrystals and achieving a Curie temperature (TC) above ambient has been elusive. Here a cocrystal between acenaphthene and 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane is presented that shows switchable remanent polarization at room temperature (TC=68 °C). Raman spectroscopy, X‐ray diffraction, and solid‐state NMR spectroscopy indicate the ferroelectric behavior is facilitated by acenaphthene (AN) rotation, deviating from conventional design strategies for CT ferroelectrics. These findings highlight the relevance of non‐CT interactions in the design of displacive ferroelectric cocrystals. 相似文献
17.
Amorphous Pure Organic Polymers for Heavy‐Atom‐Free Efficient Room‐Temperature Phosphorescence Emission 下载免费PDF全文
Prof. Xiang Ma Chao Xu Jie Wang Prof. He Tian 《Angewandte Chemie (International ed. in English)》2018,57(34):10854-10858
Pure organic, heavy‐atom‐free room‐temperature phosphorescence (RTP) materials have attracted much attention and have potential applications in photoelectric and biochemical material fields owing to their rich excited state properties. They offer long luminescent lifetime, diversified design, and facile preparation. However, recent achievements of efficient phosphorescence under ambient conditions mainly focus on ordered crystal lattices or embedding into rigid matrices, which require strict growth conditions and have poor reproducibility. Herein, we developed a concise approach to give RTP with a decent quantum yield and ultralong phosphorescence lifetime in the amorphous state by radical binary copolymerization of acrylamide and different phosphors with oxygen‐containing functional groups. The cross‐linked hydrogen‐bonding networks between the polymeric chains immobilize phosphors to suppress non‐radiative transitions and provide a microenvironment to shield quenchers. 相似文献
18.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(46):14650-14654
A viologen‐based Borromean entangled porous framework was found to be sensitive to both CuKα and MoKα X‐ray sources, showing rapid photochromic response and recovery within one minute. The X‐ray‐induced photochromic process is accompanied by a reversible single‐crystal‐to‐single‐crystal (SC‐SC) structural transformation, an unprecedented phenomenon for X‐ray sensitive materials. The complex can be further processed into portable thin films for detecting the dose of the X‐ray exposure. Moreover, the photochromism can occur over a broad temperature range of 100–333 K, both in the form of single crystals and thin films, making it a potential candidate for practical indoor and outdoor applications. 相似文献
19.
An Organic Molecule with Asymmetric Structure Exhibiting Aggregation‐Induced Emission,Delayed Fluorescence,and Mechanoluminescence 下载免费PDF全文
Shidang Xu Dr. Tingting Liu Dr. Yingxiao Mu Dr. Yi‐Fan Wang Prof. Zhenguo Chi Dr. Chang‐Cheng Lo Prof. Siwei Liu Prof. Yi Zhang Dr. Alan Lien Prof. Jiarui Xu 《Angewandte Chemie (International ed. in English)》2015,54(3):874-878
Compounds displaying delayed fluorescence (DF), from severe concentration quenching, have limited applications as nondoped organic light‐emitting diodes and material sciences. As a nondoped fluorescent emitter, aggregation‐induced emission (AIE) materials show high emission efficiency in their aggregated states. Reported herein is an AIE‐active, DF compound in which the molecular interaction is modulated, thereby promoting triplet harvesting in the solid state with a high photoluminescence quantum yield of 93.3 %, which is the highest quantum yield, to the best of our knowledge, for long‐lifetime emitters. Simultaneously, the compound with asymmetric molecular structure exhibited strong mechanoluminescence (ML) without pretreatment in the solid state, thus exploiting a design and synthetic strategy to integrate the features of DF, AIE, and ML into one compound. 相似文献
20.
Shidang Xu Tingting Liu Yingxiao Mu Yi‐Fan Wang Zhenguo Chi Chang‐Cheng Lo Siwei Liu Yi Zhang Alan Lien Jiarui Xu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(3):888-892
Compounds displaying delayed fluorescence (DF), from severe concentration quenching, have limited applications as nondoped organic light‐emitting diodes and material sciences. As a nondoped fluorescent emitter, aggregation‐induced emission (AIE) materials show high emission efficiency in their aggregated states. Reported herein is an AIE‐active, DF compound in which the molecular interaction is modulated, thereby promoting triplet harvesting in the solid state with a high photoluminescence quantum yield of 93.3 %, which is the highest quantum yield, to the best of our knowledge, for long‐lifetime emitters. Simultaneously, the compound with asymmetric molecular structure exhibited strong mechanoluminescence (ML) without pretreatment in the solid state, thus exploiting a design and synthetic strategy to integrate the features of DF, AIE, and ML into one compound. 相似文献