A Phenanthroline-Based Fluorescent Probe for Highly Selective Detection of Extreme Alkalinity (pH > 14) in Aqueous Solution

Although numerous fluorescent probes are designed to detect the pH value in the past decades, developing fluorescent probes for extreme alkalinity (pH > 14) detection in aqueous solution is still a great challenge. In this work, we utilized 1H-imidazo[4,5-f][1, 10] phenanthroline (IP) group as the recognition group of hydroxyl ion and introduced two triethylene glycol monomethyl ether groups to improve its solubility. This IP derivative, BMIP, possessed good solubility (25 mg/mL) in water. It displayed high selectivity toward extreme alkalinity (pH > 14) over other ions and pH (from extreme acidity to pH = 14). From 3 to 6 mol/L OH-, the exact concentration of OH- could be revealed by BMIP and the whole detection process just needed a short time (≤ 10 s). Meanwhile, it exhibited good anti-interference ability and repeatability during the detection process. Through optical spectra and NMR analysis, its detection mechanism was proved to be deprotonation by hydroxyl ion and then aggregation-induced enhanced emission. Our study presents a new basic group based on which researchers can develop new fluorescent probes that can detect extreme alkalinity (pH > 14) in aqueous solution.

Regulation of Singlet and Triplet Excitons in a Single Emission Layer: Efficient Fluorescent/Phosphorescent Hybrid White Organic Light-Emitting Diodes

Two efficient fluorescent molecules, viz., (E)-2-(2-4-(1-2,3-dihydrobenzo[b][1,4]dioxin-5-yl)-4,5-diphenyl-H-imidazole-2-yl)-[1,1-biphenyl]-4-yl)vinyl-1-yl(naphthalene-1-yl)-1H-phenanthro[9,10-d]imidazole (DDIBNPPI) and (E)-4-(2-(2-(-4'-1(2,3-dihyderobenzo[b][1,4]dioxin-5-yl)-4,5-diphenyl-1H-imidazole-2-yl)-[1,1'-biphenyl]-4-yl)vinyl)-1H-phenanthr[9,10-d]imidazole-1-yl)-1-napthronitrile (DDIBPPIN), were designed and synthesized. DDIBNPPI and DDIBPPIN were obtained by rupturing the covalent bond of phenanthrimidazole core to prevent aggregation-induced quenching. In DDIBPPIN, naphthonitrile group was incorporated into azomethine nitrogen of phenanthrimidazole to enhance charge-transfer ability. The DDIBPPIN/CBP:DDIBPPIN-based device shows blue emission with η_c (current efficiency) of 4.91/4.10 cd/A, η_p (power efficiency) of 4.56/3.84 lm/W, and η_ex (external quantum efficiency) of 5.11/5.96%. The η_s (exciton utilization efficiency) values of DDIPNPPI and DDIBPPIN are of 27.0 and 30.3%, respectively. The DDIPNPPI and DDIBPPIN materials employed as a host to fabricate green and red phosphorescent organic light-emitting diodes. The red/white devices (with 0.4% dopant concentration) with DDIBPPIN:Ir(MDQ)₂(acac) exhibit maximum L of 69889/26319 cd/m², η_ex of 19.6/16.6%, η_c of 34.6/35.6 cd/A, and η_p of 35.8/36.6 lm/W. The device with DDIBPPIN:Ir(ppy)₃/DDIPNPPI:Ir(ppy)₃ exhibits green emission [Commission Internationale de l'Eclairage (0.30,0.60)/(0.30,0.60)] with maximum L of 69906/69482 cd/m², η_ex of 17.9/17.0%, η_c of 59.8/58.6 cd/A, and η_p of 63.6/61.3 lm/W. The white device using DDIBPPI:Ir(ppy)₃ (with 0.4% dopant concentration) exhibits maximum L of 22152 cd/m², η_ex of 15.8%, η_c of 31.4 cd/A, and η_p of 36.1 lm/W.

2-(2-Hydroxyphenyl)imidazole-based four-coordinate organoboron compounds with efficient deep blue photoluminescence and electroluminescence

Four-coordinate organoboron compounds that can realize efficient electroluminescence with a CIE coordinate close to that of standard blue light (0.14, 0.08) have been developed.

Synthesis and photophysical properties of phenanthroimidazole–triarylborane dyads: intriguing ‘turn-on’ sensing mediated by fluoride anions

Phenanthroimidazole-based triarylborane compounds with an N-phenyl or N-biphenyl bridge were prepared and these compounds show ratiometrical ‘turn-on’ response in PL spectra upon fluoride binding to the borane moiety.

A diphenylamino-substituted quinacridone derivative: red fluorescence based on intramolecular charge-transfer transition

A red emissive quinacridone derivative has been prepared through construction of an ICT system. This resulted in the first efficient and bright red OLED based on a quinacridone derivative.

Bis(2-(benzo[d]thiazol-2-yl)-5-fluorophenolate)beryllium: a high-performance electron transport material for phosphorescent organic light-emitting devices

A beryllium complex with a low-lying LUMO level, high triplet energy and high electron mobility served as an excellent electron transport material for green, yellow and red phosphorescent OLEDs.