Amplified Spontaneous Emission from the Film of Poly(aryl ether) Dendrimer Encapsulating Excited-State Intramolecular Proton Transfer Dye

Abstract

Nonresonant exponential amplification of the excited-state intramolecular proton transfer (ESIPT) emission has been investigated with the film of ESIPT dendrimer (QG2) by pico- and femtosecond laser experiments. The intrinsic four-level nature of ESIPT and the reduced concentration quenching by dendritic effect made QG2 film an optical gain medium with the threshold intensity lower than 20 μJ/cm2/pulse. The characteristics of emission amplification are discussed in terms of the amplified spontaneous emission (ASE) related with ESIPT.

Advanced Organic Optoelectronic Materials: Harnessing Excited‐State Intramolecular Proton Transfer (ESIPT) Process

“…Effi cient ASE of ESIPT molecule was also observed in dendrimer neat fi lms [ 88 ] and highly doped polymer fi lms. [ 89 ] The second generation poly(aryl ether) dendrimer QG2 (Figure 10 a) incorporating quinoline-based ESIPT moieties showed large Stokes' shifted ( ∼ 200 nm) orange K * emission ( ∼ 570 nm) in the neat fi lm.…”

“…[ 89 ] The second generation poly(aryl ether) dendrimer QG2 (Figure 10 a) incorporating quinoline-based ESIPT moieties showed large Stokes' shifted ( ∼ 200 nm) orange K * emission ( ∼ 570 nm) in the neat fi lm. [ 88 ] Interestingly, it was observed that the fl uorescence of QG2 solution in any good solvents was very weak but that of spin-cast fi lm was quite strong due to the RIR effect described above in the section 3.2.3. When the QG2 fi lm was excited by a 355 nm picosecond laser pulse, the orange K * emission was amplifi ed and shifted to the narrow red ASE emission at 670 ∼ 695 nm.…”

Insight into the excited-state intramolecular double-proton transfer of the 2,5-bis(benzoxazol-2-yl)thiophene-3,4-diol: one-step or stepwise mechanism?

“…The excitedstate intramolecular proton transfer (ESIPT) attracts much attention particularly due to its dual emission with large Stokes' shift, which leads to its significant applications in molecular probes [5,[13][14][15][16], laser dyes [17][18][19], luminescent materials [20][21][22], chemosensors [23][24][25][26][27][28][29][30][31] and molecular logic gates [32], etc. Hence, the mechanism investigation of ESIPT is of vital importance to design, synthesize and regulate desired luminescent molecules [33][34][35][36][37].…”

Stilbene-cored poly(glutamate) dendrimers

“…In this area, the photoisomerization of dendrimers with photoresponsive cores-such as stilbene, [13][14][15][16][17][18][19][20][21] azobenzene, [22][23][24][25][26][27][28][29][30][31][32][33] diarylethene, [34][35][36][37][38] intramolecularly hydrogen-bonded chromophores, [39][40][41] and photolabile chromophores 42-44 -has been extensively investigated. We recently reported that stilbene dendrimers with benzyl ether-type dendrons exhibited a volume-conserving isomerization mechanism and a macromolecular effect (or generation effect) on energy transfer efficiency from the peripheral dendrons to the core stilbene in organic solvents [45][46][47] and aqueous solution.…”