Application of barium strontium titanate (BST) as a light sensor on led lights

Abstract

Barium Strontium Titanate (BST) film has been successfully produced as a light sensor. The BST film was made by CSD method by reacting barium acetate, strontium acetate and titanium isopropoxide with mole fractions of 0.5; 0.5 and 1, respectively.The BST absorbance test showed that BST film is sensitive to visible light ranging from 475 to 750 nm. The film test showed maximum absorbance at three peak wavelengths, 475 nm, 593 nm, and 702 nm. The energy gap of the BST film was 1.9 eV which showed that the film produced was a semiconductor. The IV test showed that BST film is a photodiode. This was indicated by the shift of the curve when tested in light and dark conditions. The sensitivity test showed BST film is most sensitive to blue light, signified by the most significant change in resistance. The decrease in resistance of blue LED was 0.401KX/lux, while the resistance decrease of green light was 0.051KX/lux and red was 0.288KX/lux. By using optical and electrical properties, BST thin film could be used as light sensors to detect LED lights.