Aggregation-Induced Emission with Large Redshift in 2,7-Diphenylfluorenone:Reality or Artifact?  

2,7-二苯芴酮伴随巨大红移的聚集诱导发光:真实还是假象?

作　　者：Xinmao Li Jianxin Guan Chuanqing Hao Zhihao Yu Junrong Zheng 李鑫茂;关键鑫;郝传清;于志浩;郑俊荣(北京大学化学与分子工程学院,北京100871)

机构地区：[1]College of Chemistry and Molecular Engineering,Beijing National Laboratory for Molecular Sciences,Peking University,Beijing 100871,China

出　　处：《Chinese Journal of Chemical Physics》2021年第6期867-873,I0004,I0091-I0093,共11页化学物理学报（英文）

基　　金：supported by the National Natural Science Foundation of China(No.21627805,No.21673004,No.21804004,and No.21821004);Ministry of Science and Technology of China(No.2017YFA0204702)。

摘　　要：The luminescence property of 2,7-diphenyl-fluorenone(DPFO)was previously reported to be very unusual with a large aggregationinduced effect associated with a fluorescence redshift of 150 nm.The phenomenon is reexamined in this work.It is found that the abnormal observations are caused by the presence of a trace amount of impurity 2,7-diphenyl-fluorene(DPF)in the as-synthesized DPFO.The pure DPFO molecule does have an intense fluorescence(FL)in solid(528 nm),about 4−5 times larger than in its dilute dichloromethane solutions(542 nm),but with a blueshifted rather than redshifted FL wavelength in solid.The enormous FL enhancement and redshifted FL wavelength of the as-synthesized DPFO solid are due to the presence of impurity DPF.The FL of DPF is much stronger than that of DPFO in dilute solutions and it also has shorter FL wavelengths.In a dilute solution of DPFO with a trace amount of DPF(∼1%),the dominant FL peaks are from DPF.Because the electronic absorption peaks of DPF overlaps with DPFO,the electronic energy of DPF can transfer to DPFO.The energy transfer is faster with the increase of concentration because DPF and surrounding DPFO molecules become closer,which quenches the FL of DPF(356 and 372 nm)and enhances the FL of DPFO(542 nm in solution and 528 nm in solid).Therefore,at high concentrations or in solids,only peak at about 542 or 528 nm shows up,and peaks at 356 and 372 nm disappear.

关 键 词：Aggregation-induced emission FLUORESCENCE IMPURITY FLUORENONE 

分 类 号：O657.3[理学—分析化学]