UPSI Digital Repository (UDRep)
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UPSI Digital Repository (UDRep)
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| Abstract : Perpustakaan Tuanku Bainun |
| This research aims to synthesise and characterise new blue phosphorescent iridium(III) complexes and analyse their photophysical properties. Three iridium(III) complexes were synthesised: bis(2-(2-butoxy-4-fluorophenyl)pyridine)(2,6 difluorobenzyltriazolpyridine)iridium(III) ion (C1), bis(2-(2-ethoxy-4- fluorophenyl)pyridine)(2,6-difluorobenzyltriazolpyridine)iridium(III) ion (C2) and bis(2-(2-butoxy-4-fluorophenyl)pyridine)(imidazolpyridine)iridium(III) ion (C3). Complexes of C1 and C2 were obtained via reaction of dichloro-bridged iridium(III) dimers with N-heterocyclic carbene ligands, while C3 was prepared using the same dimer reacted with 2-(1H-imidazol-2-yl)pyridine. All complexes were characterised using spectroscopic techniques: _H, __C and distortionless enhancement by polarisation transfer 135 (DEPT-135) nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and liquid chromatography-mass spectrometry using electrospray ionisation (LC-ESI/MS). Photophysical properties were analysed using ultravioletvisible (UV-Vis) absorption and photoluminescence (PL) spectroscopy. _H NMR spectra showed aromatic proton signals between 4.90 and 9.10 ppm attributed to phenylpyridine, triazole-derived pyridine and imidazolium moieties. __C NMR spectra showed resonances consistent with the number of carbon atoms in each complex, while DEPT-135 distinguished CH_, CH_ and CH groups. FTIR spectra confirmed the presence of phenyl and pyridine functionality groups in the ranges of 1615_1495 cm__ and 1514_1406 cm__, respectively. ESI-MS spectra displayed molecular ions [M]+ at m/z 953 (C1) and 770 (C3), while [M+Na]+ at 920 (C2). Emission spectra showed C1 and C2 emit dark blue light with a dominant emission peak (_em = 435 nm) and vibronic shoulders at 459 and 463 nm, respectively. C3 emits greenish-blue light with two emission peaks (_em = 435 and 464 nm) and vibronic shoulder at 492 nm. Among these, C1 showed the highest photoluminescence quantum yield (PLQY = 0.72) and short emission lifetime (_ = 1.36 ns). In conclusion, new blue phosphorescent iridium(III) complexes were successfully synthesised and characterised, with C1 demonstrating dark blue emission and the highest PLQY. As an implication, this study offers an alternative approach to improve blue phosphorescence efficiency in organic lightemitting diode (OLED) applications. |
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