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Frequency‐Upconverted Stimulated Emission by Up to Six‐Photon Excitation from Highly Extended Spiro‐Fused Ladder‐Type Oligo( p ‐phenylene)s
Author(s) -
Jiang Yi,
Li King Fai,
Gao Kun,
Lin He,
Tam Hoi Lam,
Liu YuanYuan,
Shu Yu,
Wong KaLeung,
Lai WenYong,
Cheah Kok Wai,
Huang Wei
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202100542
Subject(s) - excitation , fluorescence , absorption (acoustics) , phenylene , excited state , two photon excitation microscopy , materials science , laser , absorption cross section , photon , stimulated emission , conjugated system , two photon absorption , luminescence , optoelectronics , analytical chemistry (journal) , photochemistry , optics , chemistry , atomic physics , cross section (physics) , physics , polymer , quantum mechanics , composite material , chromatography
Frequency‐upconverted fluorescence and stimulated emission induced by multiphoton absorption (MPA) have attracted much interest. As compared with low‐order MPA processes, the construction of high‐order MPA processes is highly desirable and rather attractive, yet remains a formidable challenge due to its inherent low transition probability. We report the observation of the first experimental frequency‐upconverted fluorescence and stimulated emission by simultaneous six‐photon excitation in an organic molecular system. The well‐designed organic conjugated system based on cross‐shaped spiro‐fused ladder‐type oligo( p ‐phenylene)s (SpL− z , z =1–3) manifests reasonably high MPA cross‐sections and brilliant luminescence emission simultaneously. The six‐photon absorption cross‐section of SpL‐3 with an extended π‐conjugation was evaluated as 8.67×10 −169 cm 12 s 5 photon −5 . Exceptionally efficient 2‐ to 6‐photon excited stimulated emission was achieved under near‐infrared laser excitation.