Aromatic carbon nitride (PhCN) has become an important luminescent material due to its excellent optical properties and has attracted attention in photoluminescence and electroluminescence applications. Normally, PhCN is synthesized by thermal polymerization of 2,4-diamino-6-phenyl-1,3,5-triazine (DPT). However, the polymerization mechanism is still unclear. Here we investigated the polymerization process of 2,4-diamino-6-phenyl-1,3,5-triazine (DPT) at different temperatures. The results indicate that at 350 ℃, DPT decomposes into benzonitrile and cyanamide; the phenyl group does not participate in polymerization and the cyanamide polymerizes into melem. As the temperature increases to 370 ℃, the phenyl group gradually engages in polymerization, while the generation of melem diminishes and eventually ceases at 410 ℃. The characterization of its optical properties indicates that the phenyl substituent leads to an increase in the degree of conjugation and promotes the π-electron delocalization, resulting in a redshift in the UV-vis absorption and PL spectra. This work provides foundational insights into the synthesis, structure, and optical properties of PhCN, which are expected to facilitate further exploration and broader applications.
Weijing Zhang,Chunrong Zhu,Zhenjie Huang,Chengbin Gong,Qian Tang,Xiangkai Fu
Ten tripod-shaped electrochromic materials (compound 1 – 10 ) were designed and synthesized by esterification of 4,4′,4″- s -triazine-2,4,6-triyl-tribenzoic acid with different alcohols and phenols . These materials have a 2,4,6-triphenyl-1,3,5-triazine core and three ester side arms, forming an electron donor–π-acceptor structure. The electrochemical and optical properties of 1 – 10 were characterized by cyclic voltammetry and ultraviolet–visible spectroelectrochemistry . The conjugated structure of 1 – 10 markedly influenced their electrochemical properties . Electrochromic devices containing some of these compounds ( 1 , 2 , 4 , 5 , and 10 ) displayed intense color changes, fast switching times (<2 s), high optical contrast (>60%), good switching stability, high optical density (>1.0), and high coloring efficiency (>1000 cm 2 C −1 ). The colored state of these devices strongly depended on the conjugated structure of the tripod-shaped component. Short chain lengths (compounds 1 and 2 ) and electron-donating groups (compounds 4 , 5 , 8 , and 10 ) were beneficial to electrochromic properties, whereas a longer chain length (compound 3 ) and electron-withdrawing groups (compounds 6 and 9 ) adversely affected electrochromic properties.
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