Aggregation-Induced Emission and White Luminescence from a Combination of π-Conjugated Donor–Acceptor Organic Luminogens

Abstract

Two new star-shaped phenyl- and triazine-core based donor–acceptor (D–A) type conjugated molecules bearing triphenylamine end-capped arms were synthesized and characterized as imminent organic optoelectronic materials. Photophysical properties of the compounds were explored systematically via spectroscopic and theoretical methods. Because of the presence of donor–acceptor interactions, these luminogens display multifunctional properties, for instance, high extinction coefficient, large stokes shift, and pronounced solvatochromic effect. The compounds also exhibited phenomenon known as aggregation-induced emission on formation of nano-aggregates in the tetrahydrofuran–water mixture. The aggregate formation was confirmed by transmission electron microscopy, scanning electron microscopy, and dynamic light scattering analyses. Moreover, by controlling the electron withdrawing ability of the acceptor, complementary emissive fluorophores (blue and yellow) were achieved. These two complementary colors together span the entire range of visible spectrum (400–800 nm) and therefore when mixed in a requisite proportion generate white light in solution phase. These findings have potential for the progress of new organic white light radiating materials for applications in lighting and display devices.

Fused tetracyclic tris[1,2,4]triazolo[1,3,5]triazine as a novel rigid electron acceptor for efficient thermally activated delayed fluorescence emitters

“…27,28 Fortunately, the twisted D-A design strategy not only helps in rendering TADF features but also supports the integration of aggregation-induced enhanced emission (AIEE) features in the star-shaped molecules. 29 In addition, star-shaped emitters having multiple D-A transitional channels can sustain large transitional integral for a high radiative rate. Thus, via wisely choosing different cores and branches in the star-shaped molecules, the photophysical, optoelectronic and thermal properties can be easily tuned.…”

Triskelion‐Shaped π‐Luminophores Bearing Coumarin: Syntheses, Structures, and Luminescence Properties

“…This behavior is similar to that observed for a C 3 symmetrical molecule, such as a π-conjugated donor-acceptortype luminophore. [39] Thus, compound 1 b also showed AIEE characteristics similar to 1 a.…”

A DFT probe on the linear and nonlinear optical characteristics of some star‐shaped DI‐π‐DII‐Atype acetylene‐bridged rigid triazines

“…The effectiveness of B3LYP/6‐31G(d,p) method in predicting geometry of molecules under study is verified by comparing the geometry of experimentally known molecule TZ6 (from its crystal structure, CCDC: 1 850 927) with that of its computed optimized geometry. The actual torsional angle between central TZC and the immediate phenyl ring obtained from its crystal data is 1.34° (calculated torsional angle is 0.04°).…”

“…The molecules TZ1, TZ6 and TZ8 were reported to have λ exp of 304, 400, and 411 nm, respectively, while their λ cal was 283, 353 and 352 nm, respectively. The λ exp of TZ6 and TZ8 is higher as compared with their λ cal , perhaps because of redshifting of wavelength as a result of experimentally observed aggregation behavior of TZ6 in solution state and intramolecular hydrogen bonding in the case of TZ8 …”

“…The molecules in this work are equipped with electron‐donating groups (as in TZ2, TZ3, TZ4, TZ5, TZ6, TZ7, and TZ8) and electron‐withdrawing groups (as in TZ9), while considering unsubstituted TZ1 as parent molecule. The molecules included in this study, ie, TZ1, TZ3, TZ4, TZ5, TZ6, TZ7, and TZ8, are known experimentally, but their potential NLO nature was not paid attention except the parent molecule TZ1. The current computational study contributes to discover the optical nonlinearity of all the molecules under investigation along with studies of their electronic excitations.…”