Abstract
The optical properties of inorganic cesium lead bromide perovskite quantum dots (CsPbBr3-PQDs) make them particularly suitable for use as semiconductors. However, surface defects limit the performance of PQDs-based materials and devices. Consequently, this study investigated a surface passivation approach using a special polymer coating under standard conditions. In encapsulation materials, one of the most critical requirements is that the polymer should possess transparency; optical applications require material transparency to avoid affecting optical properties. Additionally, for optical compatibility, a polymer's refractive indices must be significantly different from those of emission materials, and the polymer should be amorphous. Therefore, this study investigated the basic optical properties and parameters of a polymethyl methacrylate polymer-passivated CsPbBr3-PQDs surface and compared them with a bare CsPbBr3-PQDs surface. Optical properties such as absorbance, transmittance, and reflectance are associated with important optical constants, including bandgap, absorption coefficient, extinction coefficient, refractive index, and dielectric constant. With the surface passivation approach, the surface-modification-dependent optical properties of CsPbBr3-PQDs can suppress surface states and improve the surface quality of PQDs-based materials and devices without optical contribution or structural changes. Surface passivation results in enhanced emission, which is key to improving the performance of PQDs-based optoelectronic devices.