Highly Efficient Orange-Red/Red Excimer Fluorescence from Dimeric π–π Stacking of Perylene and Its Nanoparticle Applications

Abstract

To achieve high-efficiency red excimer fluorescence, two novel perylene (PE) derivatives (mTPA-3PE and 2SF-3PE) are designed and synthesized with different monosubstituent triphenylamine (TPA) and spirofluorene (SF), respectively. The photophysical investigations reveal that mTPA-3PE and 2SF-3PE exhibit red/orange-red excimer fluorescence (637 and 610 nm) with long lifetimes (37.86 and 72.41 ns) in crystals but significantly different photoluminescence efficiencies (24 and 77%). Both crystal structure and excited-state property emphasize that the discreteness of the PE dimer with π–π stacking is essentially responsible for the high-efficiency excimer emission in the crystal. Using PE as a π–π emissive core in this work, highly efficient red excimer fluorescence is harvested in the crystal for the first time. Moreover, their nanoparticles with the same excimer fluorescence exhibit the advantage of easy processing and the promising application in cell imaging. Once again, our results validate the mechanism of excimer-induced enhanced emission (EIEE) by the discrete dimeric π–π stacking of PE in the solid state, which opens a new way to develop high-efficiency narrow band gap (e.g., near-infrared) light-emitting materials using the EIEE mechanism in the future.

Single-component panchromatic white light generation, and tuneable excimer-like visible orange and NIR emission in a Dy quinolinolate complex

“…4d) which evidence the significantly longer decay dynamics (t av = 5.5 ns) § of the EL decay at 620 nm with respect to the emission at 480 nm, displaying a sub-ns decay. 36 This observation is also confirmed by the measurements made on the isostructural gadolinium analog, 33 where no ligand to metal energy transfer can occur (vide infra), which displays an outstandingly long lived decay of hundreds of ns for the emission at 620 nm (Fig. S7 and related discussion in the ESI †).…”

“…5,8 The characteristics of the observed spectral profile are consistent with those typical of a p-stacked aromatic organic system displaying excimer-like (EL) emission. 24,36,37 Short-contact (o0.4 nm) interactions favor supramolecular energy states that give rise to intermolecular CT transitions at significantly lower energy than singlemolecule transitions. 20 As a result, intense emission in the orange-red spectral-range is observed for 1 in the crystalline state, in sharp contrast to the green monomer emission observed in diluted solution (Fig.…”

A Novel Deep Blue LE-Dominated HLCT Excited State Design Strategy and Material for OLED

“…The organic light-emitting materials play an important role in flat-panel display, solid-state lighting, photodynamic therapy, and so on [ 1 , 2 , 3 , 4 ]. These efficient fluorescent molecules often have large π-conjugation plane which could be applied in biological probes and sensors because of good biocompatibility of organic compounds [ 5 , 6 ]. According to the spin-statistics rule, the 75% spin-forbidden triplet excitons will be wasted from the lowest triplet state (T 1 ) to the ground state (S 0 ) through non-radiative transitions [ 7 , 8 , 9 , 10 ].…”

Liquid crystal behavior, photoluminescence and gas sensing: A new series of ionic liquid crystal imidazole and benzoimidazole bearing chalcone groups, synthesis and characterization

“…The band at 359 nm corresponds to the near band edge (NBE) and deep level emission (DLE), 57 while the orange-red emission at l ¼ 608 nm can be attributed to intermolecular charge transfer (ICT) and p-p stacking in the dimer system. 58,59 The emission in the blue region l ¼ 420-500 nm reveals that the material has blue light emission properties, which can be utilized in a potential application, such as OLED materials, uorescent probes in biological applications, and biotags for biological sensing applications. [60][61][62]…”