Anders Hagfeldt is professor of physical chemistry at the Swiss Federal Institute of Technology in Lausanne (EPFL). He obtained his PhD degree from Uppsala University in 1993 and was a postdoctoral fellow with Professor Michael Grätzel (1993–1994) at EPFL. His research focuses on the fields of dye-sensitized solar cells, perovskite solar cells, and solar fuels. He has published more than 510 scientific papers that have received over 60,000 citations (h index of 117). From 2014 to 2018, he was on the list of Thomson Reuter’s Highly Cited Researchers. Prof. Hagfeldt is a member of the Royal Swedish Academy of Sciences, Stockholm, and the Royal Swedish Academy of Engineering Sciences and Doctor Honoris Causa at Paris Diderot University, France. Nick Vlachopoulos obtained a degree in chemical engineering from the National Technical University of Athens, Greece (1979), and two doctorates from the University of Pennsylvania, USA (1984), and the Swiss Federal Institute of Technology in Lausanne (EPFL), Switzerland (1990). He worked as researcher in the group of Professor Michael Grätzel at EPFL (1986–1999). In 1988–1989 and in 2000-2014, he was employed as a researcher in France, Denmark, Germany, and Sweden in several areas of analytical and physical electrochemistry and as a research and development scientist at Ntera Ltd., Ireland, in electrochromic devices. In 2014, he returned to EPFL as a senior research scientist and lecturer in the group of Prof. Anders Hagfeldt. His activities have been mainly related to the application of electrochemistry in energy conversion, with particular emphasis on the molecular electrochemistry of chemically modified mesoscopic oxide electrodes and their application to solar energy.