KAJIAN PENGARUH KONSENTRASI UREA DALAM SIFAT OPTIK NANOFIBER GRAPHENE OXIDE/ PVA (POLYVINYL ALCOHOL) YANG DIFABRIKASI MENGGUNAKAN TEKNIK ELECTROSPINNING
VITA EFELINA, Dr. Iman Santoso
2015 | Tesis | S2 Ilmu FisikaTelah dilakukan kajian sifat optik nanofiber graphene oxide dengan variasi konsentrasi dopan urea. Pada penelitian ini, dikaji bagaimana pengaruh dari bentuk material graphene oxide nanofiber dan graphene oxide nanofiber yang difungsionalisasikan dengan urea terhadap besaran optik (indek bias komplek) nya. Material graphene oxide dibuat menggunakan metode Hummers. Nanofiber graphene oxide telah berhasil di buat menggunakan teknik electrospinning. Keberadaan nanofiber graphene oxide telah dikonfirmasi melalui SEM dengan terbentuknya fiber berdiameter 239± 32 nm. Sedangkan diameter fiber yang sudah ditambahkan urea sekitar 273± 31nm. Data FTIR, Raman dan dikombinasikan dengan data absorbansi menkonfirmasikan lebih lanjut adanya komposit yang terdiri atas komponen penyusun nanofiber seperti rGO, PVA dan urea. Besaran indek bias komplek telah berhasil diekstrak menggunakan analisis kramers-kronig. Data serapan dari nanofiber graphene oxide menunjukkan adanya puncak yang melebar pada energi 2.9 eV. Penambahan konsentrasi urea menyebabkan profil dari nilai koefisien ekstingsi (k) dan nilai n menurun, hal ini dimungkinkan karena adanya pita-pita baru atau semakin melebarnya celah pita. Nilai k yang semakin turun menunjukkan bahwa nanofiber graphene oxide semakin transparan dengan penambahan urea, sehingga berpotensi sebagai elektroda transparan dan konduktif.
We report how the effect of urea on optical properties graphene oxide/polyvinil alcohol (PVA) nanofibers fabricated by electrospinning technique. Graphene oxide has been prepared by oxidizing purified natural flake graphite via modified Hummers method and has been graphene oxide nanofiber doped by urea has been fabricated by using electrospinning technique with polyvinyl alcohol (PVA) as matrix of nanofibers. The samples were characterized by Scanning Electron Microscopy (SEM), Raman spectra, Fourier Transform Infrared and UV-Vis spectra for optical properties analysis. Complex optical constant such as refractive index, dielectric constant and optical conductivity are calculated from absorbance spectra are extracted using by Kramers-Kronig method. The urea doped graphene oxide nanofiber exhibited an n-type behavior. The result showed that urea doped graphene oxide nanofiber can be successfully synthesized. It was observed absorption width peak at 2.9 eV. SEM measurements show uniform hollow graphene oxide/PVA fibers formation and diameter size approximately 239± 32 nm. While graphene oxide/PVA doped urea diameter size be increased approximately 273± 31 nm. The result of UV-Vis spectroscopy showed that the greater urea for refractive index (n) and extinction coefficient (k) have a tendency to decrease the values n and k with increases of the dopant urea, so it is potentially as a transparent and conductive electrode.
Kata Kunci : Nanofiber graphene doping urea, Electrospinning, konstanta optik, kramers kronig
