Synergism between covalent and non-covalent bonds is employed to fix an organic phosphor guest in a rigid inorganic framework, simulating the stiffening effect seen in the glassy state and realizing efficient and ultralong roomtemperature phosphorescence (RTP). Twelve heavy-atom-free composites have been obtained through introducing arylboric or arylcarboxylic acid derivatives into the inorganic boric acid matrix by solid-phase synthesis. Owing to the stiffening effect of multiple bonds, all the composites show highly efficient and persistent RTP of guest molecules with a quantum yield ranging from 39.8 % to ca. 100 % and a lifetime up to 8.74 s, which results in a 55 s afterglow visible to the naked eye after exposure to a portable UV lamp. Interestingly, it is found that the substitution position and quantity of carboxyl in the guest have a great influence on the phosphorescent properties, and that the heavy-atom effect is invalid in such host-guest hybrid systems. The 100 g grade composite is easily prepared because of the solvent-free, green, and simple synthesis method. These results provide an important way for the development of RTP materials with ultrahigh quantum yield and ultralong lifetime, as well as their practical applications in the fields of anti-counterfeiting and information storage, among others.

Unique luminescence of non-conventional luminophores derived from space conjugation (SC) has recently attracted extensive interest. However, it is difficult to achieve highly efficient emission (especially white light one) from SC,...

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Herein, a series of carbon dot composites (CDC) with full‐color and long‐lived room‐temperature phosphorescence (RTP) are prepared by a simple solid‐phase one‐step method from a single non‐conjugated and non‐aromatic carbon source. The RTP emission wavelength can be adjusted from 462 to 623 nm by changing the feeding ratio and reaction temperature. The luminescent lifetime and quantum yield of a green emissive CDC (AB‐CDC‐3) reach 1.1 s and 39%, respectively, because of the close interaction between carbon dots and inorganic matrix. Due to the existence of multiple luminescent centers, these CDC exhibit excitation wavelength‐dependent RTP and a white emission when excited at a specific wavelength. A single‐component afterglow luminescent diode based on AB‐CDC‐4 shows a high‐quality white emission with CIE of (0.30, 0.33) and color‐rendering index of 88. Based on the unique photophysical properties of the composites, they exhibit huge application potential in the field of multilevel anti‐counterfeiting, fingerprint identification, and optoelectronic devices.

Synergism between covalent and non-covalent bonds is employed to fix an organic phosphor guest in a rigid inorganic framework, simulating the stiffening effect seen in the glassy state and realizing efficient and ultralong roomtemperature phosphorescence (RTP). Twelve heavy-atom-free composites have been obtained through introducing arylboric or arylcarboxylic acid derivatives into the inorganic boric acid matrix by solid-phase synthesis. Owing to the stiffening effect of multiple bonds, all the composites show highly efficient and persistent RTP of guest molecules with a quantum yield ranging from 39.8 % to ca. 100 % and a lifetime up to 8.74 s, which results in a 55 s afterglow visible to the naked eye after exposure to a portable UV lamp. Interestingly, it is found that the substitution position and quantity of carboxyl in the guest have a great influence on the phosphorescent properties, and that the heavy-atom effect is invalid in such host-guest hybrid systems. The 100 g grade composite is easily prepared because of the solvent-free, green, and simple synthesis method. These results provide an important way for the development of RTP materials with ultrahigh quantum yield and ultralong lifetime, as well as their practical applications in the fields of anti-counterfeiting and information storage, among others.

Four polyester resins with different molecular weights were used as the binder phase in silver pastes. The effects of the polyester resin molecular weight on the performance of low temperature curing silver pastes were investigated. With increasing molecular weight, the resistivity first decreased and then increased, and the sample that used a polyester resin with a weight-average molecular weight of approximately 150,000 had the lowest resistivity of 3.673 9 10 -7 X m. After folding and smoothing the sample 10 times, the silver paste that used polyester A as the binder phase had the lowest rate of resistance change of -6.70 %, and the reason for why these values were negative was investigated using scanning electron microscopy images of sample cross sections. The adhesions and stabilities of the samples were also tested.