Carbon based material for dye sensitized solar cells

Dye sensitized solar cells (DSSC) is the third generation of solar cells that promise a simple procedure and low cost material which can provide electricity by converting the light energy into electrical energy. DSSC is a sandwich-liked structure that consists of conducting electrodes, sensitizer and electrolyte. In this research, Carbon Quantum Dots (CQDs) and Reduction Graphene Oxide (RGO) are used as organic sensitizer for DSSC and then it will be examined by scanning electron microscopy, ultraviolet visible spectroscopy, Raman spectroscopy, and solar simulator to observe the optical properties, optical properties, quality and efficiency of DSSC respectively. The results show that RGO produce a higher efficiency compared to CQD as sensitizer in DSSCs

Effect of carbon quantum and graphene quantum dots on efficiency of dye-sensitized solar cells

Dye Sensitize Solar Cell (DSSC) is a photo electrochemical cell that has a comparative mechanism as photosynthesis in nature with effective electron separation, enabling the cell to perform well under overcast condition. In any case, unfortunate recombination response of generated electrons with oxidized species has limited the advancement of high performing DSSC. The recombination process can be limited by integrating photoanode film with a thickness smaller than electron diffusion length. However, a very thin photoanode film has low capability to confine light and anchor dye molecules. This study aims to improve the performance of DSSC through applying advanced material, Graphene Quantum Dots (GQDs) and Carbon Quantum Dots (CQDs) in the photoanode. Both known to have high electron mobility and high surface area with good photoluminescence properties make it a right decision to choose it as enhancer for DSSC. Photoanode was immersed in the enhancer solution in a series of adsorption time. This is to identify the optimum adsorption time for the enhancer. It has been observed that adsorption of GQDs of 48 hours achieved the highest efficiency, which is at 4.53%. Besides that, the value of short circuit current (JSC), open circuit voltage (VOC) and fill factor (FF) is 12.26 mA cm-2, 0.72 V, 0.55 sequentially. Meanwhile, the adsorption time of CQDs reached the highest efficiency, which is at 3.50% also at 48 hours. In addition, the value of short circuit current (JSC), open circuit voltage (VOC) and fill factor (FF) is 10.01 mA cm-2, 0.68 V, 0.51 consequently. Both enhancers have been observed to successfully enhance the efficiency and performance of the cell with conventional DSSC fabricated in this laboratory

Study of zinc oxide thin film characteristics

This paper presents the characterization of ZnO thin films with the thickness of 8nm, 30nm, and 200nm. The thin films were prepared using sol-gel method and has been deposited onto different substrate of silicon wafer, glass and quartz. The thin films were annealed at 400, 500 and 600°C. By using UV-Vis, the optical transmittance measurement were recorded by using a single beam spectrophotometer in the wavelength 250nm to 800nm. However, the transmittance in the visible range is hardly influenced by the film thickness, substrate used and annealed temperature and the averages are all above 80%. On surface morphology observed by AFM and FESEM, the results show that the increase of film thickness and annealed temperature will increase the mean grain size, surface-to-volume ration and RMS roughness. Besides that, higher annealing temperature cause the crystalline quality to gradually improve and the wurtzite structure of ZnO can be seen more clearly. Nonetheless, the substrate used had no effect on surface morphology, yet the uniformity of deposition on silicon wafer is better than glass and quartz

Study of zinc oxide thin film characteristics

This paper presents the characterization of ZnO thin films with the thickness of 8nm, 30nm, and 200nm. The thin films were prepared using sol-gel method and has been deposited onto different substrate of silicon wafer, glass and quartz. The thin films were annealed at 400, 500 and 600°C. By using UV-Vis, the optical transmittance measurement were recorded by using a single beam spectrophotometer in the wavelength 250nm to 800nm. However, the transmittance in the visible range is hardly influenced by the film thickness, substrate used and annealed temperature and the averages are all above 80%. On surface morphology observed by AFM and FESEM, the results show that the increase of film thickness and annealed temperature will increase the mean grain size, surface-to-volume ration and RMS roughness. Besides that, higher annealing temperature cause the crystalline quality to gradually improve and the wurtzite structure of ZnO can be seen more clearly. Nonetheless, the substrate used had no effect on surface morphology, yet the uniformity of deposition on silicon wafer is better than glass and quartz