Synthesis of large optically clear AlPO4-5 single crystals

We report the effects of gel composition and crystallization condition on the hydrothermal synthesis of optical-clear large AlPO4-5 crystals. By using a gel with excessive Al species and high HF content, large perfect hexagonal-shaped AlPO4-5 crystals (size 1.25 mm×0.65 mm) were obtained, at a synthesis temperature of 453 K with a crystallization period of 36 h. The optical quality of the crystals is sensitive to the crystallization temperature and time duration.