TY - JOUR
T1 - Supramolecular Assembly-Improved Triplet–Triplet Annihilation Upconversion in Aqueous Solution
AU - Xu, Wei
AU - Liang, Wenting
AU - Wu, Wanhua
AU - Fan, Chunying
AU - Rao, Ming
AU - Su, Dan
AU - Zhong, Zhihui
AU - Yang, Cheng
PY - 2018/11/7
Y1 - 2018/11/7
N2 - Water-soluble 9,10-diphenylanthracene-modified γ-cyclodextrin derivatives A1 and A2, in which the γ-cyclodextrin unit serves as a molecular host for a binding sensitizer, and the 9,10-diphenylanthracene moiety plays a role as an emitter/annihilator, were synthesized to investigate the supramolecular triplet–triplet annihilation (TTA) upconversion in aqueous solution. Both A1 and A2 readily aggregate and form nanoscale assemblies in water as a combined result of host–guest complexation and π–π stacking among the 9,10-diphenylanthracenes. The aggregation behavior of the supramolecular emitters was fully characterized by using a diversity of methods, including dynamic light scattering (DLS), SEM, NMR, fluorescence, and circular dichroism studies. Fluorescence spectroscopic analysis reveals that the emitters have high fluorescence quantum yields in water (82 and 90 % for A1 and A2, respectively), thus demonstrating that aggregation does not quench the fluorescence. By using a coordinated ruthenium sensitizer, a high TTA upconversion quantum yield of up to 6.9 % was observed for this supramolecular TTA system, which is significantly higher than the value (<0.5 %) obtained with nonassembled emitters in organic solvent and in contrast to the fact that TTA upconversion emission in aqueous solution is usually low or negligible. We ascribe the strong TTA upconversion emission in the present supramolecular assembly system to an efficient TTA process, which is facilitated along the stacked emitters by triplet energy migration and improved triplet–triplet energy transfer through host–guest complexation.
AB - Water-soluble 9,10-diphenylanthracene-modified γ-cyclodextrin derivatives A1 and A2, in which the γ-cyclodextrin unit serves as a molecular host for a binding sensitizer, and the 9,10-diphenylanthracene moiety plays a role as an emitter/annihilator, were synthesized to investigate the supramolecular triplet–triplet annihilation (TTA) upconversion in aqueous solution. Both A1 and A2 readily aggregate and form nanoscale assemblies in water as a combined result of host–guest complexation and π–π stacking among the 9,10-diphenylanthracenes. The aggregation behavior of the supramolecular emitters was fully characterized by using a diversity of methods, including dynamic light scattering (DLS), SEM, NMR, fluorescence, and circular dichroism studies. Fluorescence spectroscopic analysis reveals that the emitters have high fluorescence quantum yields in water (82 and 90 % for A1 and A2, respectively), thus demonstrating that aggregation does not quench the fluorescence. By using a coordinated ruthenium sensitizer, a high TTA upconversion quantum yield of up to 6.9 % was observed for this supramolecular TTA system, which is significantly higher than the value (<0.5 %) obtained with nonassembled emitters in organic solvent and in contrast to the fact that TTA upconversion emission in aqueous solution is usually low or negligible. We ascribe the strong TTA upconversion emission in the present supramolecular assembly system to an efficient TTA process, which is facilitated along the stacked emitters by triplet energy migration and improved triplet–triplet energy transfer through host–guest complexation.
KW - cyclodextrin
KW - energy transfer
KW - ruthenium
KW - supramolecular assembly
KW - triplet–triplet annihilation
UR - http://www.scopus.com/inward/record.url?scp=85055119430&partnerID=8YFLogxK
U2 - 10.1002/chem.201804001
DO - 10.1002/chem.201804001
M3 - Journal article
C2 - 30133072
AN - SCOPUS:85055119430
SN - 0947-6539
VL - 24
SP - 16677
EP - 16685
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 62
ER -