| 초록 |
The most widely used method in white light generation is combining blue LED chip with YAG:Ce yellow phosphor. However, this can be problematic in warm-white generation due to the lack of a red component, results in low color rendering index. Therefore, developing red phosphors is necessary. Among diverse red phosphor candidates, K2TiF6 has been considered as one of the most promising red emitting phosphors based on its excellent and optical properties. In this study, K2TiF6:Mn4+ phosphors were synthesized by a liquid-phase synthesis followed by cation exchange method. The K2TiF6 structure was firstly prepared by changing the solvent conditions, such as water and acetone then Mn4+ ions were adopted in K2TiF6 lattice by cation exchange, resulting in K2TiF6:Mn4+ phosphors. The properties of the prepared phosphors were analyzed and characterized by X-ray diffraction (XRD), SEM and PL measurement system. According to the XRD patters, single-phased phosphors were successively obtained under room temperature. The SEM images exhibited that the K2TiF6 prepared by using water showed several tens of micron-sized particles, whereas those prepared by using acetone showed several micron-sized particles, signifying that the solvent condition has a great effect on particle size of K2TiF6. K2TiF6:Mn4+ phosphors exhibited emission spectra in the wavelength range of 600 to 660 nm, centered at 635 nm under UV-VIS light excitation between 300 to 500 nm. The luminance of the phosphor was enhanced by increasing particle size. |
