Novel optical properties of amorphous ferric hydroxide in near infrared region

Abstract

New spectroscopic characteristics of amorphous ferric hydroxide (Fe(OH) 3 ), interestingly in the near infrared (NIR) region, are presented in this study. The absorption spectrum of ferric hydroxide covers wide spectral regions from ultraviolet to NIR (200 ~ 900 nm). Unique emission bands were newly observed in the NIR regions (800 ~ 1400 nm). Several bands of this NIR emission are quiet well overlapped with the combinational vibrational absorption bands of water. From photothermal conversion study, very interestingly, temperature of aqueous mixture solution including the amorphous ferric hydroxide was significantly increased from ambient temperature to 38 °C for 30 minutes under irradiation of a standard helium lamp.Thermal therapy is one of the popular therapeutic approaches to treat various medical conditions, such as desensitizing neuralgia, [1][2][3] obstructive tonsillar hypertrophy, 4 and killing malignant tumor.5-9