Kajian Sifat Optik pada Nanopartikel Bismuth Ferrite/Silika (BiFeO3/SiO2)

AULIA T N, Dr.Eng. Edi Suharyadi, S.Si., M.Eng.

2022 | Skripsi | S1 FISIKA

Telah dilakukan sintesis BiFeO3/SiO2 dengan konsentrasi SiO¬2 sebesar 0%, 5%, 10%, 15%, dan 20%. BiFeO3/SiO2 disintesis menggunakan metode kopresipitasi dan dikarakterisasi menggunakan X-Ray Diffractometer (XRD), spektroskopi impedansi terkomputerisasi mengukur sifat dielektriknya, dan mengukur energi gap menggunakan spektroskopi UV-Vis. Analisis kristal BiFeO3/SiO2 menghasilkan fase kristal BiFeO3, Bi25FeO40 dan Bi2Fe4O9, serta fase silika amorphous dengan Bi25FeO40 merupakan fase utama. Ukuran kristalit menurun dari 37,3±0,2 nm menjadi 22,5±0,3 nm. Nilai permitivitas dielektrik (riil dan imajiner) dan loss tangent meningkat setelah dienkapsulasi. Nilai permitivitas dielektrik riil dan imajiner terbesar dimiliki oleh sampel konsentrasi SiO2 15% dan 20% yaitu 9,32±0,06 dan 2,16±0,06. Nilai loss tangent terbesar dimiliki oleh sampel konsentrasi SiO2 20% sebesar 0,537±0,004. Energi celah pita langsung tertinggi sebesar 2,7±0,1 eV oleh sampel konsentrasi SiO2 15% dan energi celah pita tak langsung tertinggi sebesar 1,5±0,1 eV oleh sampel konsentrasi SiO2 20%.

BiFeO3/SiO2 synthesis has been carried out with SiO2 concentrations of 0%, 5%, 10%, 15%, and 20%. BiFeO3/SiO2 was synthesized using the coprecipitation method and characterized using X-Ray Diffractometer (XRD), computerized impedance spectroscopy to measure its dielectric properties, and to measure the energy gap using UV-Vis spectroscopy. Analysis of the crystals of BiFeO3/SiO2 resulted in the crystalline phases of BiFeO3, Bi25FeO40 and Bi2Fe4O9, as well as the amorphous silica phase with Bi25FeO40 as the main phase. The crystallite size decreased from 37.3±0.2 nm to 22.5±0.3 nm. The value of dielectric permittivity (real and imaginary) and loss tangent increase after encapsulation. The largest real and imaginary dielectric permittivity values were obtained by the 15% and 20% SiO2 concentration samples, namely 9.32±0.06 and 2.16±0.06, respectively. The largest loss tangent value was owned by the 20% SiO2 concentration sample of 0.537 ± 0.004. The highest direct band gap energy was 2.7±0.1 eV by the 15% SiO2 concentration sample and the highest indirect bandgap energy was 1.5±0.1 eV by the 20% SiO2 concentration sample.

Kata Kunci : nanopartikel BiFeO3, silika, sifat dielektrik, energi gap.