(B. MIPA/Sains)
Investigation of Transport Mechanism in Spirulina sp thin Films Deposited by Spin Coating to
Improve The Efficiency of Generation-4 Organic Solar Cell
Key word: thin films of spirulina sp, spin coating, carrier charge, energy gap
Utari; Purnama, Budi; Wibowo, Atmanto Heru
Fakultas MIPA UNS, Penelitian, DP2M Dikti, Penelitian Unggulan Perguruan Tinggi, 2012
Investigation of transport mechanism in spirulina sp thin films deposited by spin coating methods results have successfully carried out. The thin films were grown on the PCB with a certain pattern. In this experiment, two important experiments confirmed that the modification of the energy gap with changes in rotational speed and increasing the number of layers. The changed of the energy gap can be resoned surface modification of the spirulina sp thin films which was clarified by using scanning tunneling microscopy (STM).
Confirmation of the number of layers dependence of the energy gap indicated that energy gap decreases linearly with increasing the number of layers. In addition, absorbance value of the samples also increases with the rise of the number layers. When assuming an increase in the number layers also increases the number of charge carriers, these results indicate that the HOMO-LUMO become closer or even overlap each other. Increasing the number layers of N = 1 to N = 7, the energy gap decrease from 1.86 eV to be 1.44 eV.
While confirmation of the energy gap variation with rotational speed affirm specific dependency. At first, the energy gap increases with increasing angular velocity up to a certain critical velocity is = 4000 rpm, after which it remained constant in the energy gap Eg = 1.42 eV. Clarification of changes in the structure of the surface morphology by scanning tunneling microscopy shows that the change of morphological structure of a thin continuous layer into discrete thin layers.
