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Achieving highly efficient phosphorescence in metal-free materials under ambient conditions remains a major challenge in organic optoelectronics. Herein, we report a concise approach to obtaining pure organic phosphorescence with high quantum efficiency of up to 21.9% and millisecondscale lifetime by manipulating heavy-atom interaction based on a class of dibromobenzene derivatives in the solid state under ambient conditions. By comparing two pairs of the organic compounds designed, the one with two more bromine atoms on the alky terminals (PhBr 2 C 6 Br 2 /PhBr 2 C 8 Br 2 ) showed higher luminescence efficiency than the other one (PhBr 2 C 6 /PhBr 2 C 8 ). From the single-crystal analysis, it was proposed that the enhancement of phosphorescence resulted from increased intermolecular heavy-atom interaction in the organic crystals. Furthermore, a temperature sensor was demonstrated by using a model probe of this kind of organic phosphorescent crystals. This work not only provides a concise alternative to enhance phosphorescence in metal-free materials but also extends the scope of pure organic phosphorescent materials with high luminescent efficiency in a single component.

Using anionic surfactant as templates, ordered mesoporous silica hollow spheres (MSHSs) with radially oriented mesochannels were synthesized with the aid of ultrasonic irradiation. The product was consisted of intact and dispersed hollow spheres with the diameter mostly in the range of 100−500 nm. The hollow spheres possessed uniform shell with the thickness of 35−40 nm, and the shell with radially oriented mesopores exhibited well-ordered structure as confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. After extraction of the anionic surfactant templates by solvent, silica hollow spheres with ordered and radially oriented amino-functionalized mesochannels were obtained. Moreover, by adjustment of the sonochemical processing time, the shell thickness, mesostructure (hexagonal, radial, or disordered), and shape of the inner cavity (hexagonal or spherical shape) of the hollow spheres could be facilely tuned. The formation process of the radially ordered mesostructure could be attributed to a relatively slow cooperative realignment process of the silica/surfactant hybrid mesophase in this anionic surfactant templating system. The effectiveness of the radially aligned mesopores was validated by a drug (flurbiprofen) release experiment, in which the hollow spheres exhibited relatively high drug storage capacity (>1000 mg g−1) and much faster drug release rate than that of the flakelike mesoporous SBA-15 particles.

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A highly porous metal-organic framework (MOF) incorporating two kinds of second building units (SBUs), i.e., dimeric paddlewheel (Zn2 (COO)4 ) and tetrameric (Zn4 (O)(CO2 )6 ), is successfully assembled by the reaction of a tricarboxylate ligand with Zn(II) ion. Subsequently, single-crystal-to-single-crystal metal cation exchange using the constructed MOF is investigated, and the results show that Cu(II) and Co(II) ions can selectively be introduced into the MOF without compromising the crystallinity of the pristine framework. This metal cation-exchangeable MOF provides a useful platform for studying the metal effect on both gas adsorption and catalytic activity of the resulted MOFs. While the gas adsorption experiments reveal that Cu(II) and Co(II) exchanged samples exhibit comparable CO2 adsorption capability to the pristine Zn(II) -based MOF under the same conditions, catalytic investigations for the cycloaddition reaction of CO2 with epoxides into related carbonates demonstrate that Zn(II) -based MOF affords the highest catalytic activity as compared with Cu(II) and Co(II) exchanged ones. Molecular dynamic simulations are carried out to further confirm the catalytic performance of these constructed MOFs on chemical fixation of CO2 to carbonates. This research sheds light on how metal exchange can influence intrinsic properties of MOFs.