Photoluminescence and electroluminescence of hexaphenylsilole are enhanced by pressurization in the solid state

Abstract

Application of a hydrostatic pressure in the range of 1-650 atm boosted photoluminescence and electroluminescence of hexaphenylsilole by approximately 10 and approximately 73%, respectively, due to the suppression of intramolecular rotations and/or the increase in carrier injection, offering a helpful mechanistic insight into the intriguing phenomenon of aggregation-induced emission.

Aggregation-induced emission: phenomenon, mechanism and applications

“…Pressurization exerts complex effects on the HPS luminescence. 23 The emission is first enhanced to a plateau at a very fast speed upon pressurization, showing a unique effect of pressurization-enhanced emission or piezochromism (Fig. 4B).…”

Aggregation-Induced Emission in Group 14 Metalloles (Siloles, Germoles, and Stannoles): Spectroscopic Considerations, Substituent Effects, and Applications

“…Experiments exploring the effects of applied pressure on HPS films have demonstrated that increasing applied pressure increases the luminescence emission intensity to a point, beyond which the emission is reduced [45,120]. This finding implies that although the silole is luminescent in the film, there are voids that allow some degree of rotation of the phenyl peripheries.…”

“…As modest pressure is applied to the silole film, the molecules are forced closer together and thus the ability of their peripheral phenyl groups to rotate is reduced by increased packing density. At the higher pressures under which emission decreases, the molecules are forced so close together that increased intermolecular interactions, usually prevented by the propeller-like shape of the molecules, take over and result in excimer formation [45,120].…”

Aggregation‐Induced Emission of Multiphenyl‐Substituted 1,3‐Butadiene Derivatives: Synthesis, Properties and Application

“…[31][32][33][34][35][36] Experimental results and theoretical analysis have consistently revealed that the restriction of intramolecular motions (RIM), which includes the restriction of intramolecularr otations (RIR) and the restriction of intramolecular vibration (RIV), is attributable to the mechanism of the AIE effect. [37][38][39] There are some other mechanismsw hich can be regarded as a proof of RIV. [40] According to the RIM mechanism, the multiple aryl rotors in isolated AIEgen molecules undergod ynamic intramolecular motions on the axeso ft he bonds linked to the central stator in the solution state, which nonradiatively deactivates the energy of species in the excited state and renders AIEgen less emissive or non-emissive.…”