Abnormal Relationship between Optical Basicity and Infrared Luminescence Properties of Bismuth―doped Aluminophosphate Glass

The effect of optical basicity on near infrared (NIR) luminescence properties of bismuth―doped aluminophosphate glasses was investigated. The result show that with increase in the radius of alkali metal ions in glass host, the intensity of NIR emission band at about 1300 nm from Bi ions increases, while the intensity of NIR emission band at 1100 nm decreases. The dependence of intensity of NIR emission band at 1300 nm on the optical basicity of glass host is found to be opposite to those in previous reports as well as to that of NIR emission band at 1100 nm. The infrared emissions peaked at 1100 and 1300 nm may originate from different valent Bi ion, and the relationship between optical basicity and infrared luminescence of bismuth―doped aluminophosphate glasses can be due to the reduction effect of glass matrix.