Shape‐Memorable, Self‐Healable, Recyclable, and Full‐Color Emissive Ultralong Organic Phosphorescence Vitrimers with Exchangeable Covalent Bonds

Abstract

eye, exhibiting long lifetimes, large stokes shifts, and significant signal-to-noise ratio. [1] Among all the UOP materials, UOP polymers have advantages in terms of amorphous, flexibility, stretchability, and low cost are better candidates for future applications of bioimaging, information encryption, and foldable electronic devices. [2] Nevertheless, long-lived triplets can be easily quenched via intermolecular collision or energy transfer and thus make it difficult to achieve efficient polymeric UOP. [3] Generally, the presupposition of polymer matrix is considered as follows: (i) perfect oxygen and moisture resistance to reduce triplet excitons quenching, (ii) rigid microenvironment with rich intermolecular interactions to restrict the nonradiative pathways, (iii) high singlet and triplet energy levels to suppress the reversed energy transfer from emission center to matrix, and (iv) good mechanical strength for wide applications. [4,5] Regard to this, several linear polymers with abundant intraand intermolecular hydrogen bond are successfully used in fabrication of amorphous UOP by doping or grafting organic phosphors into the rigid matrix, such as polyvinyl alcohol, [6] poly(lactic acid), [7] polymethyl methacrylate, [8] and polyacrylamids. [9] However, hydrogen bond in such polymers is very sensitive to humidity and unfavorable for long-term stability in air. [10] Compared to these processible thermoplastics, polymeric UOP materials with covalent cross-linked bond which can supply stronger interactions between the molecular chains exhibit superior environmental resistance, higher quantum efficiently (Φ P ), and longer lifetime (τ) due to efficient suppression of excited-state vibrations in the rigid networks. [2,11] Unfortunately, cross-linked polymers are regularly defined as traditional thermosets that lack recyclability, reprocessing, and environmental friendly features. [1b] Besides, the full-wavelength range color tuning with good purity in cross-linked polymeric UOP is rarely demonstrated.In 2011, vitrimers which rely on reversible transesterifications in epoxy/acid and epoxy/anhydride polyester networks with dynamic bond exchange mechanism were developed by Leibler's group (Figure 1a and Figure S1, Supporting Information). [12] The exchangeable covalent bonds triggered above topology freezing transition temperature (T v ) enable covalent cross-linked thermosets with features such as self-healing, Polymeric materials displaying ultralong organic phosphorescence (UOP) have drawn much attention in the fields of optoelectronics, bioimaging, and information encryption. However, it is challenging to realize polymeric UOP materials with variable mechanical strength, self-healing, and superior processability. This work presents a low-cost strategy to achieve polymeric UOP with full-color-emission (doping vitrimers with different phosphorescent emitters) by introducing exchangeable covalent cross-linked bonds. These amorphous polymers show ultralong lifetimes up to 1.75 s under ambient conditions. Impress...

Monitoring of Sweat pH and Dual‐Mode Anti‐Counterfeiting from Metal‐Organic Framework‐Based Multifunctional Gel

“…On the other hand, 7H‐dibenzo[ c , g ]carbazole (DBCZ) [ 33 ] emitted blue fluorescence and yellow‐green RTP under 365 nm excitation. According to the energy level diagrams of similar molecules and the previous reports, [ 33‐35 ] the RTP emission for DBCZ might be ascribed to the transition from T 1 to S 0 .…”

Efficient, Multicolored, and Stable Room‐Temperature Phosphorescence Doped Materials Based on a Lead Halide Matrix: A Coordination‐Driven Doping Strategy

“…On the other hand, it can form coordination bond with the matrix to serve as a bridge for energy transfer between host and guest, thus further improving the RTP efficiency. The reported literatures show that guest molecules can also be fixed in host matrix by covalent grafting, [30][31][32] but the formation of covalent bonds often requires specific grafting sites and complex reaction conditions. In contrast, host-guest interaction based on coordination is easy to form, which is more conducive to the construction of host-guest DSs.…”

“…), [26][27][28][29] and has limited ability to fix guest molecules, resulting in low RTP efficiency. Although in a few cases covalent grafting has been used to enhance the immobilization of guest molecules, [30][31][32] the formation of covalent bonds often involves complicated chemical reaction, which is not conducive to practical application. Comparatively, coordination bond has the characteristics of moderate strength and easy formation.…”

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“…The change in modulus of the polymer involves variations in the network’s free volume or cross-linking density, and the emission of RTP from chromophores is closely related to the rigid environment of the polymer and can be programmably modulated on demand. For example, the rigid environment of the polymer can constrain the rotational and vibrational thermal motions of organic chromophores, thereby inhibiting the nonradiative decay of triplet excitons and achieving RTP . However, constructing such a self-stiffening polymer system is highly difficult if not impossible.…”

“…For example, the rigid environment of the polymer can constrain the rotational and vibrational thermal motions of organic chromophores, thereby inhibiting the nonradiative decay of triplet excitons and achieving RTP. 34 However, constructing such a self-stiffening polymer system is highly difficult if not impossible.…”