“Carbon-Based Compounds and Materials for Enhanced Solar Cell Efficiencies and for Electrocatalytic Applications for Hydrogen Formation”
Carbon-based chemical compounds and materials are relatively inexpensive and very effective as selective Electron Transporting Layers (ETLs) in solar cells. Our work in this area has been primarily with buckminsterfullerene compounds, also called “buckyballs” or simply fullerenes, which are pure-carbon cages that are excellent electron acceptors and 3D transporters. We have functionalized fullerenes in order to modulate and probe their specific interfacial interactions in perovskite solar cells to understand the details and to enhance the cell performance efficiencies. Pyridine-functionalized fullerenes were tested as ETLs, see picture, both as pure compounds as well as in combination with other ETL compounds in order to discriminate their ability to extract electrons at the perovskite interface and to transport the electrons through the bulk phase. Results clearly showed that the pyridine-functionalized compounds act as efficient electron extractors at the interface but are not necessarily good electron transporters as a bulk phase.
In addition to regular fullerenes we have also worked with endohedral versions, carbon cages which encapsulate ions and/or atoms and clusters inside, stabilized by electronic interactions with the cages. These nano-sized compounds, which we also call “Buckyball Maracas” due to their composition and structure, were recently shown to act as reasonably efficient non-precious metal-containing molecular catalysts to effect the Hydrogen Evolution Reaction (HER), or water splitting, to produce hydrogen gas, see JACS cover. These are preliminary results and we are currently exploring the fundamental aspects of the HER with other endohedral fullerene compounds, both to understand the details and to increase their efficiencies.
 Olivia Fernandez-Delgado, P. S. Chandrasekhar, Natalia Cano, Zoe C. Simon, Alain. R. Puente-Santiago, Fang Liu, Edison Castro, and Luis Echegoyen, “The Role of Fullerene Derivatives in Perovskite Solar Cells: Electron Transporting or Electron Extraction Layers?” J. Mater. Chem. C, 9, 10759 – 10767, 2021.
 O. Fernandez-Delgado, A.R. Puente Santiago, J. Galindo Betancourt, M.F. Sanad S. Sreenivsan, and L. Echegoyen, “Diazonium Functionalized Fullerenes: A New Class of Efficient Molecular Catalysts for the Hydrogen Evolution Reactions,” Nanoscale, 2021.
 Alain Puente Santiago, Mohamed Sanad, Antonio Moreno-Vicente, Md Ariful Ahsan, Maira Ceron, Yangrong Yao, Sreeprasad Sreenivasan, Antonio Rodriguez-Fortea, Josep Poblet and Luis Echegoyen, “A new class of molecular HER electrocatalysts: catalytic activity of M3N@C2n (C2n=68, 78, 80) fullerenes,” J. Am. Chem. Soc., 143(16), 6037-6042, 2021.
Hosted by Professor Jason Zhang