KAJIAN SIFAT OPTIK PADA LAPISAN TIPIS REDUCED GRAPHENE OXIDE/PCBM (FENIL-C61-BUTIYRIC ACID METHYL ESTER)

JASDAR AGUS, Dr. Iman Santoso

2016 | Tesis | S2 Ilmu Fisika

Telah dilakukan kajian sifat optik lapisan tipis reduced graphene oxide (rGO) doping fenil-C61-butiyric acid methyl ester (PCBM). Pengkajian sifat optik pada penelitian ini dilakukan melalui penentuan indek bias kompleks (N vektor = n + ik), kostanta dielektrik real dan imajiner (epsilon 1 dan epsilon 2) dan nilai optical conductivity bagian real (sigma 1). Reduced graphene oxide dibuat menggunakan metode Hummer dan lapisan tipis rGO/PCBM dibuat menggunakan teknik spin coating di atas substrat quartz. Proses pemberian doping PCBM pada larutan rGO dilakukan secara kimia dengan mencampurkan PCBM sebesar 0.05 ml, 0.1 ml. 0.2 ml, 0.4 ml, 0.6 ml, 0.8 ml dan 1 ml ke larutan rGO dengan bantuan surfaktan tween sebagai perekat air dan dichlorobenzene yang masing-masing merupakan pelarut rGO dan PCBM. Karakterisasi pada penelitian menggunakan FTIR, Raman dan dikombinasikan dengan data absorbansi untuk menentukan karakteristik optik dari material. Besaran indek bias kompleks telah berhasil diekstrak menggunakan analisis Kramers-Kronig. Penambahan konsentrasi PCBM menyebabkan profil dari nilai koefisien ekstingsi (k), nilai epsilon 2 dan nilai sigma1 menurun, dari rentang 1,5 sampai 6,2 eV. Namun pada rentang energi 1,5-3,0 eV terlihat penurunan nilai k dan epsilon 2 yang cukup signifikan. Sedangkan pola perubahan nilai n dan epsilon 1 dengan penambahan PCBM dibagi menjadi 3 bagian yaitu pola perubahan bagian rentang energi rendah pada 1,5-2,7 eV, rentang energi sedang pada 2,8-5,0 dan rentang energi tinggi pada 5,1-6,2. Sementara melalui analisis effective medium approximation (EMA) menggunakan persamaan Bruggeman didapatkan udara, air, rGO, GO dan dichlorobenzene dalam komposit lapisan tipis material. Nilai k yang semakin turun dari rentang 1,5 sampai 6,2 eV menunjukkan bahwa lapisan tipis reduced graphene oxide semakin transparan dengan penambahan PCBM, sementara nilai sigma 1 juga menurun pada rentang yang sama sehingga berpotensi diaplikasikan sebagai bagian aktif sel surya organik.

We report on how the effect of fenil-C61-butiyric acid methyl ester (PCBM) on optical properties of reduced graphene oxide thin film. Assessment optical properties of this research by determining the complex refractive index (N vector = n + ik), real and imaginary dielectric constants (epsilon 1 and epsilon 2) and the value of the real of optical conductivity (sigma 1). Graphene oxide has been prepared by oxidizing purified natural flake graphite via modified Hummers method and has been reduced graphene oxide thin film doped by PCBM has been fabricated by using spin coating technique. PCBM doped process of giving a solution of rGO performed chemically by mixed PCBM of 0.05 ml, 0.1 ml. 0.2 ml, 0.4 ml, 0.6 ml, 0.8 ml and 1 ml solution to rGO with the aid of a surfactant tween as adhesive water and dichlorobenzene, each of which is a solvent rGO and PCBM. The samples were characterized by FTIR, Raman and combined with the data absorbance to determinited the optical characteristics of the material. The magnitude of the complex refractive index has been successfully extracted used Kramers-Kronig analysis. The addition of PCBM concentration led to the profile of the value of extinction coefficient (k), epsilon 2 value and the value sigma 1 are decreasesed, from the range of 1.5 to 6.2 eV. But the energy range 1.5-3.0 eV noticeable decrease in the value of k and epsilon 2 significant. While the change in the value of n and epsilon 1 with the addition of PCBM is divided into 3 regions. The first area is in the range from 1.5 to 2.7 eV energy, the second region is in the range from 2.8 to 5 eV and the third area is in the range from 5.1 to 6.2 eV. While going through the analysis of effective medium approximation (EMA) got air, water, rGO, GO and dichlorobenzene in a thin film of composite material. K values were getting down from the range of 1.5 to 6.2 eV showed that reduced graphene oxide thin film more transparent with the addition of PCBM, while the value sigma 1 also decreased in the same range, thereby potentially as active cell on organic solar cell.

Kata Kunci : Graphene Oxide, Spin coating, konstanta optik, Kramers-Kronig.