In recent years, several studies have been conducted on rare-earth ions doped in various crystalline and non-crystalline materials in order to understand their spectroscopic properties. The majority of light sources are designed with doping of Dy3+ ions [1,2]. Luminescence properties of the Dy3+ ions are related to the intra configural f-f transition. White light can be created by mixing not only the three primary red, green, and blue colors. Additionally, it is important to gain the yellow emission source. There is possible to fabricate white light emission with suitable color temperature and chromaticity coordinates by adjusting the blue-to-yellow intensity ratio in Dy3+-doped luminescence materials, appropriately. Therefore, new nanocrystals doped with Dy3+ions were proposed.
Microwave assisted hydrothermal techniques were used to synthesize silicon-substituted apatite doped with Dy3+ ions. The luminescence properties were investigated, including the UV-VIS absorption, and excitation spectra, emission spectra, and decay profiles. The spectra were used for further calculation.
According to XRD powder diffraction, obtained nanocrystals have hexagonal structures, with the P63/m space group. The size in the range of 20-80 nm was confirmed by the Rietveld calculations and TEM images. The EDX study revealed the presence of silicon and dysprosium elemtnts with the concentration related to a theoretical estimate. This study is focused on spectroscopic properties of the obtained materials showing the critical concentration of the luminescence quenching. Radiative f-f transitions from the excited states to the ground states are responsible for the luminescence of RE3+ ions. In order to determine the critical radius between opticaly active ions there is needed to analyze the emission spectra. The highest luminescence intensity was observed for a 1 mol% Dy3+ ion doping. The critical distance was estimated to be equal to 10.79 Å. A value higher than 5 Å indicates that the interaction between active ions is a multipole-multipole.
An important factor analyzed for the potential light source is the emission coloor and correlated color temperature (CCT). Both parameters were evaluated. It was found that emission was characterized by the yellowish-green color, and CCT in the range of 4400-5600 K.