title: Organic Crystals with Near-Infrared Amplified Spontaneous Emissions Based on 2'-Hydroxychalcone Derivatives: Subtle Structure Modification but Great Property Change.
abstract: A series of highly efficient deep red to near-infrared (NIR) emissive organic crystals 1-3 based on the structurally simple 2'-hydroxychalcone derivatives were synthesized through a simple one-step condensation reaction. Crystal 1 displays the highest quantum yield (Φf) of 0.32 among the reported organic single crystals with an emission maximum (λem) over 710 nm. Comparison between the bright emissive crystals 1-3 and the nearly nonluminous compounds 4-7 clearly gives evidence that a subtle structure modification can arouse great property changes, which is instructive in designing new high-efficiency organic luminescent materials. Notably, crystals 1-3 exhibit amplified spontaneous emissions (ASE) with extremely low thresholds. Thus, organic deep red to NIR emissive crystals with very high Φf have been obtained and are found to display the first example of NIR fluorescent crystal ASE.
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Street, Changchun (P. R. China).
authors.forename: Xiao
authors.initials: X
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Street, Changchun (P. R. China).
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Street, Changchun (P. R. China).
authors.forename: Shuo
authors.initials: S
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Street, Changchun (P. R. China).
authors.forename: Houyu
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Street, Changchun (P. R. China). hongyuzhang@jlu.edu.cn.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Street, Changchun (P. R. China).
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
mesh_terms: D047188:Chalcones / Q000737:chemistry*; D003460:Crystallization; D049449:Luminescence; D049408:Luminescent Agents / Q000737:chemistry*; D008958:Models, Molecular; D019265:Spectroscopy, Near-Infrared
chemical_list: D047188:Chalcones; D049408:Luminescent Agents; C013031:2'-hydroxychalcone
keywords: amplified spontaneous emission; near-infrared spectroscopy; organic crystals; proton transfer; π-conjugation