SONOCHEMICAL SYNTHESIS OF MG2SNO4 AND MG2SNO4:M (M= TI4+, CO2+) PHOSPHOR MATERIAL

• Main Author: Reksa Ananda, Vatra
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/52267
• Institution: Institut Teknologi Bandung

LED (Light Emitting Diode) is a semiconductor device which emits light when it is given electric current. The LED performance improvement as a light source device can be carried out by developing a new phosphor material. This new phosphor have a new color coverage (color gamut) thus it gives new color emission for LED. The goals of this research are to synthesize and determine the photoluminescence mechanism in Mg2SnO4 and Mg2SnO4:M (M= Ti4+, Co2+) phosphor for LED application. The Mg2SnO4 and Mg2SnO4:M (M= Ti4+, Co2+) phosphors which were synthesized via sonochemical method were characterized by XRD (X- ray Diffraction) and UV-DRS (UV- Diffuse Reflectance Spectroscopy) measurement. XRD results showed that Mg2SnO4 and Mg2SnO4:M (M= Ti4+, Co2+) are in single phase. From Rietveld refinement analysis, structural model of Mg2SnO4 and Mg2SnO4:M (M= Ti4+, Co2+) are obtained as cubic inverse spinel structure. UV-DRS results showed that Mg2SnO4 absorbs light in the range of 235 nm – 250 nm, Mg2Sn0,99Ti0,01O4 absorbs light in the range of 300 nm – 372 nm, and Mg1,99Co0,01SnO4 absorbs light in the range of 220 nm – 368 nm. Those light absorptions are related to charge transfer of electrons from O2- to Sn4+. Mg2Sn0,99Ti0,01O4 absorbs light in the range of 217 nm – 300 nm, which is related to VB to Ti 3d (eg) electronic transition. Mg1,99Co0,01SnO4 also have multiple absorption peaks in the range of 500 nm – 700 nm, which is attributed to tetrahedrally coordinated Co2+ energy level 4A2(4F) to 2A1(2G), 2E(2G), and 4T1(4P) transitions. Mg2SnO4, Mg2Sn0,99Ti0,01O4, and Mg1,99Co0,01SnO4 have bandgap value of 4,55 eV; 4,63 eV; and 4,96 eV, respectively. Photoluminescence mechanism of Mg2SnO4 involve the excitation process from VB to CB and then, it is followed by radiative relaxation from CB to Sn2+ lone pair defect energy level, which results in green emission. Photoluminescence mechanism of Mg2Sn0,99Ti0,01O4 involve excitation process from VB to Ti 3d (eg) energy level and then it is followed by radiative relaxation from Ti 3d (t2g) energy level to VB, which results in blue emission. Photoluminescence mechanism of Mg1,99Co0,01SnO4 involve the excitation process from 4A2(4F) to 2A1(2G), 2E(2G), and 4T1(4P) energy level of tetrahedrally coordinated Co2+ and then it is followed by radiative relaxation from 4T1(4P) to 4A2(4F) transition, which results in red emission.