Emission and Color Tuning of Cyanostilbenes and White Light Emission

Abstract

White-light-emitting diodes are energy efficiency replacement of conventional lighting sources. Herein, we report the luminescent behavior of three simple cyanostilbenes with triphenylamine-donating groups bearing different electron-withdrawing groups (phenyl, pyridyl, and p -nitrophenyl) in a common donor (D)−π–acceptor (A) α-cyanostilbene construct along with their thermal and electrochemical properties. The density functional theory (DFT) studies reveal that aggregation-induced emission characteristic feature of the D−π–A dyes is inversely proportional to the intramolecular charge transfer (ICT) effect, that is, phenyl-and pyridyl-substituted compounds show characteristic aggregation-induced emission in water, whereas the ICT effect is dominant for the nitro derivative. The extent of ICT and the solvatochromic emission shifts, from blue to red, depend on the strength of the electron-withdrawing group. White luminescence and tunable emission colors are obtained by careful admixtures of these cyanostilbenes bearing triphenylamines. The results rationalized through DFT and time-dependent DFT calculations follow a consistent trend with the energy levels measured from the electrochemical and optical studies. Thermogravimetric analysis and differential scanning calorimetry studies showed excellent thermal stability of the compounds. The scanning electron microscopy and dynamic light scattering measurements were performed to reveal the formation of aggregates. This strategy involving synthetically simple and structurally similar molecules with different emission properties has potential applications in the fabrication of multicolor and white-light-emitting materials.

New Dual-Mode Orthogonal Tunable Fluorescence Systems Based on Cucurbit[8]Uril: White Light, 3d Printing and Anti-Counterfeit Applications

“…[1][2] Moreover, systems that combine cucurbiturils with fluorescent dye guests and enable such systems to act as fluorescent switches or sensors are of great interest. [3][4][5][6] In this area, Scherman et al (with Q [8]), [7] Zhang et al…”

Shedding light on predicting and controlling emission chromaticity in multicomponent photoluminescent systems

“…8 These systems include but are not limited to mixed-emitting organic polymers, 9 host-guest metal-organic hybrids, 10,11 and simple mixtures of photoluminescent (PL) organic molecules. [12][13][14][15] The emission chromaticity of multicomponent PL systems can be tuned by choice of excitation wavelength and varying the composition of each PL emitter. 12,16,17 For example, there have been multiple accounts of multicomponent PLCT being used to achieve highly sought-after white light emission (WLE) by adjusting the composition of each PL component.…”

“…12,16,17 For example, there have been multiple accounts of multicomponent PLCT being used to achieve highly sought-after white light emission (WLE) by adjusting the composition of each PL component. 1,12,13,15,18 Despite countless examples of multicomponent WLE PL systems, most appear to have arisen through an iterative process of varying the excitation wavelength and composition of RGB emitters as opposed to predicting and programming WLE into systems using the concept of additive colour mixing.…”

Two Pyridine‐Based Fluorescent Probes for Sensing pH

“…In addition, some groups reported a lot of compounds that bridged pyridine and aryl groups through acrylonitrile and respectively studied their properties such as kinetics, spectroscopy, pH sensing, lightemitting diodes, etc. [46][47][48][49] But so far, little work has been done on this kind of compounds as pH probes.…”

“…The nitrogen atom within the pyridine ring has been widely used because of the combinable nature between the lone pair electron of nitrogen and proton. In addition, some groups reported a lot of compounds that bridged pyridine and aryl groups through acrylonitrile and respectively studied their properties such as kinetics, spectroscopy, pH sensing, light‐emitting diodes, etc [46–49] . But so far, little work has been done on this kind of compounds as pH probes.…”