IN-SITU STUDY OF 2D ORGANIC HYBRID PEROVSKITES AT THE AIR-WATER INTERFACE

Perovskites have aroused a great interest due to their excellent optical properties that make them a very attractive material as a component, among others, of solar cells. Optimizing the nature and architecture of the material, it has been possible to increase the conversion efficiency in solar cells until 25.7%. However, these materials present structural defects which decrease its stability due to charge recombination. To improve its stability, surface passivation using quaternary ammonium salts was proposed. The passivated material is obtained in bulk and further transferred to a solid by drop casting or spin coating. However, these techniques often drive to non-uniform or clumped films of the low quality. To solve this problem, we have designed a new preparation procedure based on the Langmuir- Schaefer methodology. However, high quality perovskites require an elevate order degree which depends on the structure of the surface state of the film transferred from the air-liquid interface to the solid. Therefore, the main objective of the proposal is understanding of structure of perovskites formed at the different packing densities using Neutron Reflectometry.