Green emitting β$\ubeta$‐SiAlON:Eu2+ phosphors derived from chemically modified perhydropolysilazanes

Abstract

AbstractWe report the first synthesis of β‐SiAlON:Eu2+ phosphors from single‐source precursors, perhydropolysilazane (PHPS), chemically modified with Al(OCH(CH3)2)3, and EuCl2. The reactions occurring during the precursor synthesis and the subsequent thermal conversion of polymeric precursors into β‐SiAlON:Eu2+ phosphors have been studied by a complementary set of analytical techniques, including infrared spectroscopy, gas chromatography–mass spectrometry, thermogravimetry–mass spectrometry, X‐ray diffraction (XRD), photoluminescence spectroscopy, and scanning electron microscopy. It has been clearly established that Al(OCH(CH3)2)3 immediately reacted with PHPS to afford N–Al bonds at room temperature, whereas N–Eu bond formation was suggested to proceed above 600°C accompanied by the elimination of HCl up to 1000°C in flowing N2. The subsequent 1800°C‐heat treatment for 1 h under an N2 gas pressure at 980 kPa allowed converting the single‐source precursors into fine‐grained β‐SiAlON:Eu2+ phosphors. XRD analysis revealed that the Al/Si of .09 was the critical atomic ratio in the precursor synthesis to afford single‐phase β‐SiAlON (z = .55). Moreover, Eu2+‐doping was found to efficiently reduce the carbon impurity in the host β‐SiAlON. The polymer‐derived β‐SiAlON:Eu2+ phosphors exhibited green emission under excitation at 460 nm and achieved the highest green emission intensity at the critical dopant Eu2+ concentration at 1.48 at%.