Aggregation‐Induced Emission Characteristics of o‐Carborane‐Functionalized Tetraphenylethylene Luminogens: The Influence of Carborane Cages on Photoluminescence

Abstract

Tetraphenylethylene (TPE)-carborane hybrids are constructed, and the impact of carborane substituents on the aggregation-induced emission (AIE) characteristics of TPE-cores has been investigated. When altering the 2-R-group on the carborane unit with -H, -CH or phenyl group, the luminescent quantum yield of the corresponding TPE derivatives can be manipulated from 0.18 to 0.63 in the solid state. The emission color exhibits an obvious 100 nm shift (from blue to yellow).

Carborane‐Induced Excimer Emission of Severely Twisted Bis‐o‐Carboranyl Chrysene

“…Remarkably, this is, to the best of our knowledge, the first example of an excimer species involving a carborane with ICT character. Secondly, and in line with many similar carborane‐containing fluorophores,13, 14, 15, 17, 18, 19, 20, 22, 31, 32 the AIE observed for 2 is the result of a unimolecular ICT species. These two points may also be used to rationalize the differences between the emission efficiencies recorded from the two long‐wavelength emissions.…”

“…These ICT states are notable for their flexible carboranyl C−C bond, which can vibrate and relax non‐radiatively, or radiatively with a highly red‐shifted emission 24, 25, 26, 27, 28, 29, 30. Such systems often exhibit aggregation‐induced emission (AIE),13, 14, 15, 17, 18, 19, 20, 22, 31, 32 that is, in an aggregated state where molecular motion is restricted, non‐radiative relaxation pathways from the ICT state are inhibited, leading to a significant increase in emission efficiency. It has been demonstrated that incorporation of bulky carboranes on the long edges of linear acenes creates a large steric hinderance between the carboranes and proximal protons, leading to a considerable deformation of the ring system 15, 16, 17.…”

Modulation of the cis‐ and trans‐Conformations in Bis‐o‐carborane Substituted Benzodithiophenes and Emission Enhancement Effect on Luminescent Efficiency by Solidification

“…Even though intense luminescence can be observed in the solution state, optical properties were often spoiled through ACQ by intermolecular interactions in the solid state. [5][6][7] It has been reported that some of the o-carborane [8][9][10][11][12][13] derivatives presented AIE [14][15][16][17][18][19][20][21] and can be applied as a solid-state luminescent material. [1][2][3] Intense solid-state luminescent properties originating from AIE were found and applied for developing the conjugated materials, including polymers.…”

Enhancement of Aggregation-Induced Emission by Introducing Multiple o-Carborane Substitutions into Triphenylamine

“…Indeed, applicability of the modified o -carboranes for organic light-emitting devices has been demonstrated from the recent studies [ 30 , 31 ]. Moreover, it should be noted that some of the modified o -carboranes also showed AIE [ 23 , 24 , 30 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. In the solution state, the modified o -carboranes presented slight emission as a result of emission annihilation by molecular motions, while intense emission was recovered because of low mobility in the solid state.…”