Kok-wai Cheah

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Benefitting from the flexibility in engineering their optical response, metamaterials have been used to achieve control over the propagation of light to an unprecedented level, leading to highly unconventional and versatile optical functionalities compared with their natural counterparts. Recently, the emerging field of metasurfaces, which consist of a(More)
The cyclometalated platinum(II) complex [Pt(L)Cl], where HL is a new cyclometalating ligand 2-phenyl-6-(1H-pyrazol-3-yl)pyridine containing C(phenyl), N(pyridyl), and N(pyrazolyl) donor moieties, was found to possess two-photon-induced luminescent properties. The two-photon-absorption cross section of the complex in N,N-dimethylformamide at room temperature(More)
A novel approach based on conjugation interruption has been developed and is presented for a series of luminescent and thermally stable chalcogen-bridged platinum(II) polyyne polymers trans-[{-Pt(PBu3)2C[triple bond]C(C6H4)E(C6H4)C[triple bond]C-}n] (E = O, S, SO, SO2). Particular attention was focused on the photophysical properties of these Group 10(More)
A series of luminescent platinum(II) alkynyl complexes containing 2,5-diphenyl-1,3,4-oxadiazole (oxa-2,5) and 10,15-dihydro-5H-diindeno[1,2-a;1',2'-c]fluorene (truxene) as the cores and different electron donors at the periphery has been synthesized and characterized. These complexes showed long-lived emissions in both solution and in the solid state at(More)
Fluorescence spectrum of EuS4N complex at low temperature is very different from that at room temperature. When temperature changes, shapes of both excitation and emission spectra change dramatically at about 160 K, which is taken as an indicator of the structural change of EuS4N. Peak splitting of 5D0-->7F0 also indicates that there are two different types(More)
We report the first observation of three photon induced NIR emission (890–1,400 nm) with NIR excitation (800 nm) from a newly synthesized organic neodymium complex with known molecular structure, suggests the potential use of lanthanide probes for use in three-dimensional imaging and further the study of multi- photon induced emission process in(More)