Perovskite Solar Cells (PSCs)
Solar energy is one of the most promising alternatives to meet world energy demands. In this regard, PSCs have emerged as a very promising new type of photovoltaic technology due to their low-cost, ease of fabrication and high power conversion eﬃciency (PCE) above 23%, which is higher than that obtained with polycrystalline silicon, while using 1000 times less light harvesting material.
Fullerenes and their derivatives are the most used n-type Electron Transporting Materials (ETMs) in inverted PSCs due to their eﬃcient electron transporting and solution processable properties, low temperature fabrication, suitable energy level alignment with that of the perovskites, and acceptable electron mobilities. Even though phenyl-C60-butyric acid methyl ester (PC61BM) is the most used fullerene, in our group we synthesize new fullerene derivatives with carefully selected functionalities for enhanced photovoltaic performance to improve not only the efficiencies of the PSCs but the stability of the devices and the mobility of the charges.
Synthesis of Endohedral Fullerenes
Endohedral fullerenes are carbon cages containing incarcerated atoms, metals or clusters. The interaction between the cage and the incarcerated moiety can provide interesting electronic properties. Our research group has contributed extensively to the discovery of new endohedral fullerenes. Currently, we are focusing on the synthesis and discovery of new endohedral fullerenes that encapsulate new atoms and/ or of new clusters. These fullerenes could potentially possess new and interesting optoelectronic properties and have interesting applications, mainly in organic photovoltaic technologies of particular interest are Uranium-based endohedral compounds.
Functionalization of Fullerenes
The functionalization of fullerene cages has expanded their potential application in several fields, from biology to materials science. Our research group currently works in the regioselective addition to fullerene cages to obtain pure mono and bis-adducts. These regioselectively prepared pure mono and bis-adducts are being used as ETMs in PSC devices.
Extended Fullerene Networks
Fullerenes possess interesting physical and electronic properties that have allowed them to be used in numerous applications. Our interest is focused on the design and synthesis of regioisomerically pure fullerene derivatives that could potentially be incorporated as linkers in extended network structures, mainly in metal organic frameworks (MOFs) and metallopolymers.
Metal Organic Frameworks (MOFs):
Fullerenes have demonstrated hydrogen storage abilities and possess rich redox properties. Our research group currently works on the preparation of fullerene derivatives that can be incorporated as linkers in totally novel MOFs and to determine their gas adsorption properties. Additionally, the preparation of fullerene extended networks using bimetallic units as redox centers will supplement the already rich redox properties of fullerenes.
Complexation of regioisomerically pure fullerene derivatives with different metals and ligands are being used for the synthesis of polymeric materials. The electronic properties of these materials are of interest.
Biological Applications of Fullerenes
Fullerenes have attracted increasing attention for different biological applications such as, radical scavenging and HIV inhibition, despite their low water-solubility. Our research group is working on the functionalization of fullerene cages to increase their solubility in aqueous media through the preparation of pyrrolidinium salt derivatives and the addition of addends containing polar groups.