Keywords : Porphyrin, TiO 2, solar cell, photosensitizing
By: Agus Supriyanto, Riyatun, Erlina
Isolation of natural porphyrin from microalgae spirulina has been carried out extraction and chromatography. The porphyrin solution characterized inckuded the spectroscopy UV-Vis absoprtion, spectroscopy FTIR and I-V (currentvoltage) characterization to determine the photoconductivity. The result of characterization shows that microalgae spirulinahas better porphyrin content and relative easily gets its porphyrin compound isolation. The absoprtion spectrum obtained has 410 nm soret band and 660 nm Q band, apparently consistent with the typical porphyrin spectrum. Its dark conductivity reaches about 10,74×10-6 ohm- 1.cm-1 becomes 15,43 x10-6 ohm -1.cm-1 for conductivity with the condition given radiation intensity of 100 mW/cm2.
The porphyrin thin film was growth using spin coating method. The parameter growth inclede the variation of porphyrin solution concentration, spin rotation speed, temperature thin film, and duration of temperature thin film. The absorption spectrum formed is the same as the porphyrin solution condition, namely at 410 nm and 660 nm. The results of parameter growth are the concentration of porphyrin is at 5,67 μg/mL, rotation speed was 1500 rpm with time at 60 seconds, and temperature thin film was below 200o C with duration at 15 minutes. The morphology of porphyrin thin films was characterized using AFM (atomic force microscopy), and its electrical property using I-V curve.
Fabrication of solar cell organic devices, the porphyrin thin films structure was combined with the semiconductor material of TiO2 nanopartikel film. The first device structure was ITO/TiO2/Porphyr in/Alumunium and the second one ITO/Porphyrin/TiO2/Alumunium has. Each structure of solar cell organic devices was optimized porphyrin thin film namely 1, 3, 5 and 7 times layer coating. The solar cell organic devices has been tested in dark and under various illumination of light intensity from 20 to 100 mWcm-2. The device shows the rectification property in dark and shows the photosensitizing effect under illumination. The device with 3 times layer coating of porphyrin shows the highest Jsc of 5.76 μAcm-2, Voc of 648 and efficiency 0.17 % for ITO/Porphyrin/TiO2/Alumunium structure device.