STUDY OF THE INFLUENCE OF ADDING FUMED SILICA ON OPTICAL PROPERTIES OF BLUE EMISSION PEROVSKITE CH3NH3PBBR3/PMMA COMPOSITE FILMS

• Main Author: Rahmatul Ummah, Auliya
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/62510
• Institution: Institut Teknologi Bandung

One of the most promising materials for optoelectronic device applications, particularly lighting devices, is organic-inorganic halide perovskite. This is due to the adjustable emission wavelengths, high emission intensity, and comparatively simple solution-based fabrication process of organic-inorganic halide perovskites. Green and red emission from a methylammonium (CH3NH3)-based organic-inorganic halide perovskite has been extensively reported, and the emission spectrum exhibits outstanding intensity and stability. Even yet, due to its drawbacks, such as low emission intensity and instability of the emission spectrum in the open air, the synthesis of a hybrid organic-inorganic perovskite based on methylammonium (CH3NH3) blue emission with excellent emission-quality remains a problem. CH3NH3Pb(Br/Cl)3 is a CH3NH3-based blue emission perovskite that is usually made by combining chlorine and bromine components. However, combining Cl- and Br- ions may result in inhomogeneous particle distribution, causing the emission spectrum to change from blue to green. The use of perovskite CH3NH3Pb(Br/Cl)3 in the applications of optoelectronic devices may be hampered by this weakness. As a result, it is critical to conduct the synthesis of CH3NH3PbBr3 blue emission perovskite using a single halide component. To achieve optimum blue emission, a CH3NH3PbBr3/PMMA perovskite composite layer was produced with varied OA:OLAm ligand ratios. Meanwhile, adjustments in the addition of fumed silica are used to strengthen the stability of the blue emission spectrum. Because it is very simple, cost-effective, and has numerous customizable parameters, the Ligand-Assisted Reprecipitation Process (LARP) technique was used to make the colloidal CH3NH3PbBr3 perovskite. The composite film was synthesized using the drop-casting method, which did not need any difficult procedures and resulted in a composite film with a reasonably acceptable morphology. The samples were given OA:OLAm ligand ratios of 1:0.1 M, 1:0.15 M, 1:0.25 M, and 1:0.35 M. At a ratio of 1:0.25 M, colloid CH3NH3PbBr3 perovskite emits excellent blue emission. The sample with this ratio has an excitonic peak of 441 nm and an optimum blue emission peak of 471 nm in its absorbance spectrum. This is because, as revealed by Transmission Electron Microscopy (TEM) tests, high OLAm concentrations may create a tiny perovskite particle size distribution of roughly 5.73 nm. Excitonic absorption peaks at lower wavelengths are produced by perovskite particles of this size, resulting in blue emission. Fumed silica optimization was used to improve the emission spectrum stability of the CH3NH3PbBr3/PMMA perovskite composite film. The adjustment of fumed silica concentration during the synthesis of CH3NH3PbBr3/PMMA and CH3NH3PbBr3/PMMA/SiO2 perovskite composite films can retain good optical characteristics of blue emission in both the absorbance and emission spectra. From the colloidal phase, the emission peak of the CH3NH3PbBr3/PMMA/SiO2 perovskite composite film may be maintained, specifically in the 472 nm wavelength range. The sample's surface structure is likewise in the shape of tiny grains with a uniform distribution. The intensity of the stability of the fumed silica sample against air, water (H2O), and high temperature is also successfully maintained. This is because fumed silica optimization leads to strong surface contact with ligands and control of perovskite particle size on the fumed silica surface. The ligands in the perovskite material become more stable as a consequence of the surface contact, and particle size management results in improved optical characteristics. The optical characteristics of the CH3NH3PbBr3/PMMA/SiO2 perovskite composite layer were optimized, allowing perovskite to be used in optoelectronic devices, particularly lighting systems.