Publications by authors named "Yi-Chun Wong"

The rational design of a new class of photoresponsive tris(8-hydroxyquinolinato)aluminum(III) (Alq) complexes has been developed. By incorporating the photochromic dithienylethene units with different peripheral heterocycles into the Alq framework, the photochromic properties as well as photoswitching efficiency can be readily modulated, through effective photocyclization of the Al(III) complex. Such intrinsic photochromic behavior leads to the unprecedented enhancement in the electron-transporting properties as demonstrated by the as-fabricated electron-only device, rendering the realization of photoswitchable electron mobility.

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A new class of fused heterocyclic tridentate ligand-containing alkynylgold(III) complexes with tunable emission color has been successfully designed and synthesized. Structural modification of the σ-donating fused heterocyclic alkynyl ligands, including substituted fluorene, carbazole, and triphenylamine, enables a large spectral shift of about 110 nm (ca. 3310 cm ) that covers the green to red region to be realized with the same tridentate ligand-containing alkynylgold(III) complexes in solid-state thin films.

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A new class of donor-acceptor type luminescent bis(alkynyl)gold(iii) N⁁C complexes has been synthesized and characterized. These gold(iii) complexes not only exhibit high photoluminescence quantum yields of up to 0.81, but also interesting mechanochromic luminescence behaviors that are reversible.

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A series of luminescent cyclometalated N^C^N [N^C^N = 1,3-bis(N-alkylbenzimidazol-2'-yl)benzene]platinum(II) alkynyl and carbazolyl complexes has been prepared. The structure of one platinum(II) carbazolyl complex has been characterized by X-ray crystallography. The corresponding electrochemical and photophysical properties have been explored and analyzed.

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A new class of tridentate ligand-containing cyclometalated gold(III) complexes featuring dendritic alkynyl ligands with carbazole moieties as dendrons and peripheral groups has been synthesized up to the third generation. High-performance solution-processable organic light-emitting devices (OLEDs) with maximum current efficiency of up to 23.7 cd A and external quantum efficiency of up to 6.

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A new class of highly luminescent bipolar alkynylplatinum(II) complexes has been synthesized, characterized, and applied as phosphorescent dopants in the fabrication of solution-processable organic light-emitting devices (OLEDs). Through the incorporation of a delicate balance of electron-donating carbazole moieties and electron-accepting phenylbenzimidazole or oxadiazole moieties into the platinum(II) core, the platinum(II) complexes have been demonstrated to exhibit bipolar charge transport character with high photoluminescence quantum yields of up to 0.75 in thin films.

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A new class of cyclometalated tetradentate alkynylgold(III) complexes has been successfully synthesized by post-synthetic modification. Through the judicious design and choice of pincer ligands, post-synthetic cyclization could be achieved to produce the robust and structurally rigid class of tetradentate gold(III) C^N^C^C complexes with high photoluminescence quantum yields of up to 0.49 in solution and 0.

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A series of heterocyclic spiro derivatives has been successfully synthesized and characterized by photophysical and electrochemical studies. Taking advantage of their excellent hole-transporting properties, highly efficient small-molecular organic photovoltaic devices based on these heterocyclic compounds as donors with very low dopant concentrations have been prepared; particularly, a high open-circuit voltage of up to 1.10 V and a power conversion efficiency of up to 5.

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A series of air-stable spiro-fused ladder-type boron(III) compounds has been designed, synthesized, and the electrochemistry and photophysical behavior have been characterized. By simply varying the substituents on the pyridine ring and extending the π-conjugation of the spiro framework, the emission color of these compounds can be easily fine-tuned spanning the visible spectrum from blue to red. All compounds exhibit a broad and structureless emission band across the entire visible region, assigned as an intramolecular charge-transfer transition originating from the thiophene of the spiro framework to the pyridine-borane moieties.

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A new class of luminescent dendritic carbazole-containing alkynylplatinum(II) complexes has been synthesized, characterized, and applied as phosphorescent dopants in the fabrication of solution-processable organic light-emitting devices (OLEDs). These complexes exhibit high photoluminescence quantum yields of up to 80% in spin-coated thin films. In addition, the incorporation of carbazole dendrons into the platinum(II) center can significantly suppress intermolecular interactions in solid-state thin films, giving rise to emission spectra that are similar to those found in solution irrespective of dopant concentrations.

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A new class of bipolar alkynylgold(III) complexes containing triphenylamine and benzimidazole moieties has been synthesized, characterized, and applied as phosphorescent dopants in the fabrication of solution-processable organic light-emitting devices (OLEDs). The incorporation of methyl groups in the central phenyl unit has been found to rigidify the molecule to reduce nonradiative decay, yielding a high photoluminescence quantum yield of up to 75% in spin-coated thin films. In addition, the realization of highly efficient solution-processable OLEDs with an extremely small external quantum efficiency (EQE) roll-off has been demonstrated.

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A novel isoquinoline-containing C^N^C ligand and its phosphorescent triphenylamine-based alkynylgold(III) dendrimers have been synthesized. These alkynylgold(III) dendrimers serve as phosphorescent dopants in the fabrication of efficient solution-processable organic light-emitting devices (OLEDs). The photophysical, electrochemical, and electroluminescence properties were studied.

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