Optimized Synthesis of Solution‐Processable Crystalline Poly(Triazine Imide) with Minimized Defects for OLED Application

Abstract

Poly(triazine imide) (PTI) is a highly crystalline semiconductor, and though no techniques exist that enable synthesis of macroscopic monolayers of PTI, it is possible to study it in thin layer device applications that are compatible with its polycrystalline, nanoscale morphology. We find that the by‐product of conventional PTI synthesis is a C−C carbon‐rich phase that is detrimental for charge transport and photoluminescence. An optimized synthetic protocol yields a PTI material with an increased quantum yield, enabled photocurrent and electroluminescence. We report that protonation of the PTI structure happens preferentially at the pyridinic N atoms of the triazine rings, is accompanied by exfoliation of PTI layers, and contributes to increases in quantum yield and exciton lifetimes. This study describes structure–property relationships in PTI that link the nature of defects, their formation, and how to avoid them with the optical and electronic performance of PTI. On the basis of our findings, we create an OLED prototype with PTI as the active, metal‐free material.

Influence of Ion Exchange on Photoresponsive Properties of Potassium Poly(heptazine imide)

“…Previous studies have shown that the absorption edge of HPHI is located on the short wavelength side compared to that of KPHI, and the results here are qualitatively consistent with this. It has recently been reported that the absorption edge is blue-shifted in PTI when the metal ion is replaced by H + , which is consistent with the trend observed for HPHI …”

“…For example, transition-metal dichalcogenides , and covalent organic frameworks, in addition to graphene derivatives, have been considered promising candidates. The potential of several CN polymers for optoelectronic functional materials has hardly been explored, partly because of the difficulty in preparing highly crystalline samples. , Poly­(triazine imide) (PTI), which has a structure similar to that of PHI with triazine as the building unit, has been acknowledged as a potential electroluminescent material, but it is still not being actively studied. The situation is similar for MPHI.…”

Polarity-Ultrasensitive and Lipophilicity-Enhanced Structurally Modified Hemicyanine for Two-Color Staining to Reveal Cell Apoptosis during Chemotherapy

“…The chemical modifications enhanced the values of log P and p K b in the molecules, which satisfied the criteria for mitochondria accumulation and avoided the lysosomal uptake effects . The log P of Cy1321 is determined to be 16.5 (Figure b), and the p K b is calculated to be 13.6 based on fluorescence titration assay (Figure c) . The bis-cholesterol architecture is anticipated to be anchored on the inner membrane of the mitochondria.…”

“…37 The log P of Cy1321 is determined to be 16.5 (Figure 1b), and the pK b is calculated to be 13.6 based on fluorescence titration assay (Figure 1c). 38 The bis-cholesterol architecture is anticipated to be anchored on the inner membrane of the mitochondria. Owing to its advantages of ultrasensitivity toward polarity, Cy1321 is presumed to perceive the polarity variations in the metabolic and even the PCD process within the mitochondria.…”

Engineering Coinage Metal Nanoclusters for Electroluminescent Light-Emitting Diodes

“…The device structure of MNCs based on electroluminescent LEDs is similar to that of traditional OLEDs, which is a typical carrier injection electroluminescent device with a “sandwich” structure, and MNCs’ thin film is used as the light-emitting layer [ 69 , 70 , 71 , 72 ]. As shown in Figure 6 , electroluminescent LEDs are generally composed of a hole transport layer (HTL), a light-emitting layer, an electron transport layer (ETL), and electrodes, and corresponding interface modifications can be performed between the layers according to special requirements.…”