Synthesis of hybrid metalorganic/inorganic systems and doped halide thin films for photovoltaics

Abstract

The aim of the present PhD thesis has been the synthesis of novel materials for photovoltaic (PV) technologies. One possible way to increase the conversion efficiency of silicon solar cells is to shift the incident sunlight spectrum, converting photons poorly exploited by the active PV material into more effective photons. The materials studied as energy converters, consist of thin film layers integrated in the PV panel and made of a host material and an active luminescent species. In the present thesis, the energy conversion systems made of lanthanide doped fluorides (CaF2, NaYF4, NaGdF4, KYF4 and YOF) have been synthetized using MOCVD and sol-gel methods and deeply studied for their potential integration in silicon solar cells. Together with the traditional silicon PV technology, a new class of PV materials, based on inorganic multi-junction technology, new hybrid materials and organic dye-sensitized solar cells (DSSC) is subject of interest in the last years. Hybrid metalorganic/inorganic systems of Eu-complex/NiO films have been developed for the DSSC technology and for the potential improvement of the PV material with new functionalities, that combine the semiconductor behavior of the inorganic part to the luminescent properties of the metalorganic component. The all-inorganic halide perovskite CsPbBr3 has been synthetized through a precipitation method. The perovskite CsPbBr3 has a semiconductor behavior, with an energy band gap useful in the PV application and has the advantages to not have any labile or expensive organic components.