MORPHOLOGICAL STUDY OF BICONTINUOUS CONCENTRIC LAMELLAR SILICA SYNTHESIZED AT ATMOSPHERIC PRESSURE AND ITS APPLICATION AS INTERNAL MICRO REFLECTOR IN DSSC

• Main Author: Silmi, Nadiatus
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/55395
• Institution: Institut Teknologi Bandung

KCC-1, nanostructured silica material with bicontinuous concentric lamellar (bcl) morphology provides plenty of functional characteristics, such as open channel structure, excellent accessibility, and large surface area. Unique morphological features of KCC-1 are suitable for a wide range of applications, including photocatalysis and solar-energy harvesting. Although bcl silica exhibits a variety of superior properties, studies on morphology and its application in dye-sensitized solar cells (DSSC) are still limited. Therefore, this work aims to study the influence of synthesized time on the morphology of bcl silica. Moreover, we used the synthesized bcl silica as internal micro reflectors in DSSC. The bcl silica was synthesized using the reflux method with varying synthesized times. The morphology of bcl silica was observed using FESEM and HRTEM. Observations using FESEM showed that the synthesized bcl silica was spherical with a diameter ranging from 196–525 nm. FESEM images also show that bcl silica has bicontinuous lamellar walls with a thickness of 9–11 nm that arranged concentrically to form a spherical shape particle. As the synthesis time increases, the average particle size of bcl silica gets larger. FESEM images can be further analyzed using ImageJ software to obtain binary images. The quantization of bcl silica binary images shows that the cross-sectional area ratio of lamella increases with increasing synthesis time. The simulation of Cahn-Hilliard's spinodal decomposition model using MATLAB can also describe the lamella cross-sectional area ratio of bcl silica. In addition, to characterize the FESEM image's texture, a Shannon entropy calculation can be performed. HRTEM observations showed that bcl silica particles consist of lamellar walls arranged concentrically and distributed uniformly in all directions. HRTEM images can be further processed using ImageJ software to plot a gray value intensity that describes the material's morphological profile. The line and circular gray value intensity plots of the HRTEM image show that the bcl silica has a denser core than the outer part. The denser core proves that the lamella in bcl silica is concentrically arranged towards the particle core. The bcl silica synthesized for 48 hours has the greatest concentricity. In this study, the development of photoanodes was carried out with the addition of bcl silica which acts as an internal micro reflector. Photoanodes with 10% bcl silica produced the highest efficiency with a value of 2.813%. Such efficiency increased by 25.4% from photoanodes without internal micro reflectors. The addition of internal micro reflectors can improve the overall performance of DSSC cells. However, after adding bcl silica above 10%, the resulting cell efficiency tends to be stable at 2.5%. Meanwhile, photoanodes with 10% bcl silica synthesized for 6 hours provided higher efficiency (2.715%) than bcl silica synthesized for 18 and 72 hours.