AIE/ACQ Effects in Two DR/NIR Emitters: A Structural and DFT Comparative Analysis

Abstract

The effects of aggregation-induced emission (AIE) and of aggregation caused quenching (ACQ) were observed and discussed on two solid materials based on a phenylenevinylene (PV) and a dicyano-PV structure. The brightest emitter in solid films shows a high fluorescence quantum yield in the deep red/near IR (DR/NIR) region (75%). The spectroscopic properties of the two crystalline solids have been described and compared in terms of crystallographic data and time dependent DFT analysis. The influence of the cyano-substituents on AIE/ACQ mechanism activation was discussed.

Spectroscopic Behaviour of Two Novel Azobenzene Fluorescent Dyes and Their Polymeric Blends

“…Different dye percentages were tested in order to get better PL performance. As expected on the base of our previous study [48][49][50][51], the best emission for both samples was recorded on the more diluted blends (10 wt%), where the ACQ effect is attenuated.…”

Color Tuning in the Luminescence of Two Oligomers Derived from N,N′-(Naphthalenediyl)bis-phenylimine Containing Oligomers

“…In Figure 3, the neat solid NPh2 and NPh5 samples (first line) are compared with NPh2 and NPh5 PVK blends (second line). is doping percent was optimal in previous work on organic dopants [41,44,61] taking into account the PL performance, the processability, and also the costs of the system.…”

“…e insertion of the bulky benzoyloxy groups in the oligomeric Schiff base derivatives was expected to provide good PL performance also in the solid state [32][33][34][35][36][37]. Flexible chain length turned out to be an important structural factor influencing the aggregation structures [38][39][40][41][42][43][44][45] and hence the emission of the compounds, both in colour and intensity. Very impressively, a dimer and a pentamer with the same fluorogenic core and terminal groups emit two different colours, blue and yellow, in dependence to the different molecular weight (MW) values.…”

Novel Solid-State Emissive Polymers and Polymeric Blends from a T-Shaped Benzodifuran Scaffold: A Comparative Study

“…As a matrix typically employed in OLEDs (Organic Light Emitting Diode) construction [44] PVK is a conductive amorphous scarcely emissive and highly processable host polymer. The dye-doped blends can be a way for some chromophore to relieve ACQ effect [11], because the system resemble a diluted solid solution of the emitters frozen in an amorphous medium. In the present case, the analysis of the emission properties was carried out on PVK blends of the active units M1 and M2.…”

“…The factors governing solid-state emission of organic polymers are conjugation length, planarity and intramolecular interactions. The use of traditional fluorophores is limited due to aggregation-caused quenching (ACQ) effect [9][10][11][12]. The use of encumbered substituents is an effective strategy in preventing nonradiative decay channels, due to inter-chain interactions [13,14], and for suppressing dissipation pathways of the excited state energy.…”