Konstantinos Fostiropoulos

Fostiropoulos was born 20 June 1960 in Krya Vrysi, Pella, Greece, to Anastasios Fostiropoulos and Lemonia Fostiropoulou (née Atmatzidou) the second of three children (Niko, Kosta, Eleni). In 1961 his father emigrated to Mannheim, Germany, where later his wife followed with their two sons when Fostiropoulos was four years old. There, five years later his sister Eleni was born. Until they retired his parents Anastasios and Lemonia had been working as labourer and cleaner, respectively. In 2015 they re-immigrated in Greece, together with his sister Eleni and her family. His brother Niko has been elected town counsellor in Karlsruhe, Germany and is owner of the centre for further education alfatraining.

During his time as research fellow at the Institut für Medienkommunikation (IMK) of the former GMD-Forschungszentrum Informationstechnik in Sankt Augustin near Bonn, Fostiropoulos' relationship to his colleague Simone Lahme, a web designer and specialist for e-learning, began on the occasion of the Total Solar eclipse of August 11, 1999, which they had been observing together in Karlsruhe. They married in 2004 and have two children, Timon and Melina.

First micro-graphs of fullerene crystals grown from benzene solution. The images were taken through an optical microscope in reflection mode. Flake-lets of some 10 microns in diameter as well as compact hexagonal rods and stars had been identified. (Fostiropoulos, 1990)

In September 1987 a young volunteering student, Bernd Wagner,[11] joined the "Dust Group" of astrophysicist Hugo Fechtig at Max Planck Institute for Nuclear Physics for a few weeks. There, under the supervision of Fechtig's assistant Wolfgang Krätschmer Wagner had been performing such carbon vapour experiments using the contact arc method (2) when he accidentally changed the pressure conditions. As a result, he received traces of carbon dust with additional weak IR absorption features unknown to him. However, the result was not considered further, when Wagner left, but was deemed "impurities from pump oil"[12] or simply "junk".[13]
In January 1989 Fostiropoulos joined Fechtig's group, where he picked up the "accidental" experiment. After a few weeks assessment period he decided to study as part of his Ph.D. the three kinds of thermal evaporation processes in detail and, subsequently, he developed new process parameters for each. Accordingly, in 1989 Fostiropoulos was the first to synthesize C₆₀ the first molecular carbon modification[3][4] applying initially a contact arc process (2) with specific experimental conditions for fast electrode degradation, hence, accelerated carbon evaporation. Moreover, he developed a method to sinter graphite rods from commercially available "amorphous" ¹³C carbon dust. Applying a resistive heating process (3) and using such "isotopic" graphite rods, a few days before New Year's Eve 1989, he synthesized for the first time an unusual material which contained an exotic species: "isotopic" ¹³C₆₀,[14] From that he, casually, proved the existence of an all-carbon molecule with icosahedral "platonic" symmetry and truncated icosahedron "archimedean" shape predicted by Kroto et al. 1985: C₆₀ "Buckminsterfullerene"![5]

C₆₀ publication activities triggered by the Heidelberg experiments 1990[15]

In his effort to push the production yield further he then focused his research on the simple arc method (1) that culminated in 1990 in a yield of > 1 gram per day[4] achieved by a robust and highly efficient arc process. As the fullerene material, however, was still embedded in the generated soot Fostiropoulos developed two possible extraction methods, either by applying thermal evaporation to expel the molecular species C₆₀, C₇₀... from the soot under vacuum conditions or by dispersing the soot in benzene where only fullerenes dissolve. The extracted powder of this "natural" pure fullerene mixture was analyzed by optical (UV to IR) as well as mass spectroscopy where also the "American football" shaped C₇₀ was found. From the powder he could grow for the first time ultra-thin C₆₀ films by vacuum thermal evaporation and watch the formation of hexagonal crystals from the "wine-red" benzene solution. From subsequent thin film chromatography studies[16] the wine-red colour turned out to originate from the 10% C₇₀ fraction in the natural fullerene mixture. The mass density of the novel Carbon crystals was determined experimentally as well as theoretically using data from a TEM crystal analysis measured for the first time in collaboration with Werner Kühlbrandt,[17] EMBL Heidelberg, where the van der Waals diameter of the molecular "football" was determined: d_C60= 1.0 nm. In collaboration with Hans Hermann Eysel, Institute of Inorganic Chemistry, Heidelberg University, for the first time Raman spectra of C₆₀ have been measured.

Université Pierre-et-Marie-Curie Paris VI campus de Jussieu

Beginning of 1991 Fostiropoulos was invited to visit the research group of astrophysicist Alain Léger at Paris University VI for two months where they performed matrix isolation spectroscopy on C⁻
₆₀ and C⁺
₆₀ ions in cold Ne matrices in order to measure their optical absorptions under quasi-space conditions. Particularly, the positive ion was a potential candidate for the carrier of Diffuse Interstellar Bands as discussed independently by Harry Kroto 1987.[18] An immediate proposal in cooperation with Fostiropoulos submitted by Alain Léger and Louis Le Sergeant d'Hendecourt for one week observing time at the Canada-France Hawaii Telescope in order to search for C⁺
₆₀ fingerprints in the interstellar medium had been accepted. However, subsequently, the MPI in Heidelberg rejected its, hence, Fostiropoulos' participation in the search for C⁺
₆₀ in the interstellar medium.
After all, in 1994 the hunt for the spectral fingerprints of the interstellar football provided a first paper where Bernard Foing and Pascale Ehrenfreund identified the molecule as carrier of two diffuse interstellar bands.[19] Their estimation has been confirmed in many other papers that roughly 0.1% (!) of all carbon in the interstellar medium exists as "C₆₀ - a new form of carbon".

With his results on the synthesis, extraction and characterization of fullerenes published 1990 in NATURE[20] (ResearchGate: 6.748 citations, as at January 2020) and some astrophysical aspects of ionized and hydrogenated C₆₀ which he found in his data Fostiropoulos hastily completed his Ph.D. thesis by the end of 1991[21] that has been triggering waves of publications worldwide since then.[22]

Before their publication in NATURE a patent application based on the results of the Heidelberg experiments had been filed[23] with a US Patent Office in Tucson, Arizona. Principal applicant had been the University of Arizona,[24] whereas the claims of the MPI Heidelberg had been limited to the statutory minimum.[25] Ten days later a follow-up application in favour of a private investor has been filed there, too.[26] After one year a European Patent has been filed under the title "New form of carbon".[27] Fostiropoulos had not been informed prior to the patent applications.

Few months after Fostiropoulos began his research on the strange soot Krätschmer recommended to stop this vain undertaking and focus on astrophysically relevant carbon clusters like C₂, C₃, C₄...[28] Therefore, Fostiropoulos decided to waste 18 months (= Ph.D. halftime) playing football and if there would be no positive result he would switch to "reasonable" carbon clusters. After 12 months intensive research, however, he succeeded to prove the existence of the all-carbon molecule with icosahedral symmetry (isotopic ¹³C₆₀) and after 15 months (around 1 May 1990) he had optimized the synthesis yield and accomplished to extract the fullerene powder from the soot. After 18 months they submitted their NATURE publication.[20]

In summer 1990 during a cooperation at the Heidelberg University on Raman spectroscopy to verify the hypothetical "football" structure of the molecule one of the partners expressed carefully his concerns: "hopefully it is not a cold fusion ;-)" referring to the most famous erratum at that time published by Martin Fleischmann et al. 1989.

The NATURE publication[20] had been accepted 7 September 1990. On this occasion Fostiropoulos had the opportunity to meet and discuss with Rick Smalley the later Nobel Laureate (1996) on a conference when he invited him and Krätschmer "to come to Konstanz and use a fraction of Smalley's lecture time" (12 September 1990) where Krätschmer reported their break-through in preparation of large amounts of fullerenes.[29] A few days later Harry Kroto, also Nobei Laureate (1996), and his wife Margaret unexpectedly visited the Heidelberg scientists on their way back from a conference in Yugoslavia. Kroto[30] presented Fostiropoulos and Krätschmer with a bottle of "red wine" Châteauneuf-du-Pape 1985. On the last working day before Christmas 1990 Fostiropoulos and Krätschmer enjoyed Kroto's wine at the Max Planck Institute in Heidelberg.

On the occasion of Fostiropoulos' final Ph.D. thesis presentation to the Department of Cosmophysics of the institute he invited young Bernd Wagner[11] to the talk as his guest in order to meet him in person and introduce him to the department as the lucky guy who kicked off the Heidelberg part of the C₆₀ story.

After the abortion of his first scientific career by the end of 1993 Fostiropoulos worked in various jobs from 1994 till 1997 when he joined the Hellenic Army to perform his military service.

In 1998 Fostiropoulos resumed scientific activities joining the Institute for Media Communication at the former German National Research Centre for Information Technology GMD-Forschungszentrum Informationstechnik for three years where he participated in IT projects in the field of distance education. He had been running a JAVA based platform for regular lectures from Schloss Birlinghoven (GMD headquarters) to the Geneva University. For the first time internet connectivity including satellite transmission (EUTELSAT) was used to set-up a transatlantic teaching network between the then CAPE consortium of the University of Pennsylvania, via GMD, to ICI at Bucharest University as well as the Bulgarian Academy of Sciences in Sofia demonstrating transatlantic tele-teaching capability with video-conference and lecture notes through low bandwidth internet applications.[8]

The research field of organic solar cells (OSC) is divided in two parts. Most scientists use wet chemical methods applying polymer materials as one of the two components to form the absorber layer of the devices, whereas the use of small absorber molecules deposited by vacuum thermal evaporation techniques is rather a niche of the field. However, in both concepts C₆₀ is the other important component of the absorber because of its extraordinary electron acceptor properties. In 2002 Fostiropoulos presented a bi-layer heterojunction absorber concept with Zn-phthalocyanine and C₆₀ molecules as donor and acceptor materials, respectively.[7] Thus, he achieved a power conversion efficiency of η=2.5% which was the world record for small molecules OSC at that time catching up a similar record of polymer solar cells (2001-2003 by Brabec, Sariciftci, Hummelen 2001[31][32]). In 2003 these two records brought the field into focus of solar energy research[33] which had been the beginning of a generous funding period in Germany for the field of organic photovoltaics that lasted more than a decade.

In December 2003 Fostiropoulos founded the Organic Solar Cells Group at the Institute Heterogeneous Material Systems within the Helmholtz-Zentrum Berlin (the then Hahn-Meitner-Institut). He was awarded more than two million € mainly from the Federal Ministries BMU and BMBF, to a minor degree also by the Solar Energy Division at HMI to build and equip laboratories[34] for the development of vacuum preparation techniques for ultra-thin organic layer systems. Since then, the two ministries have been directly financing the Organic Solar Cells Group activities by ≈ 4 M€ additional project funding. From 2014 on Fostiropoulos has been focussing on hybrid Perovskite solar cells whereupon his group developed an industrially relevant all-vacuum fabrication method for such devices.[35]

Aristotle University of Thessaloniki, "ΜΟΥΣAIΣ ΧΑΡΙΣΙ ΘΥΕ" (="Sacrifice in the Muses and Graces")

Fostiropoulos had been teaching at Heidelberg University, Free University Berlin, Potsdam University as well as Aristotle University of Thessaloniki (AUTh) in the fields of physical chemistry, soft matter physics and organic photovoltaics. During a four years period from 2011 to 2014 he had been visiting AUTh three months per year where he had been giving lectures in the Ph.D. program of the Department of Physics and collaborated with Stergios Logothetidis and the LTFN - "Laboratory for Thin Films Nanosystems and Nanometrology" in the field of organic electronic materials and devices. Thus, he had the opportunity to experience the financial crisis of his country up close.

In the frame of EU project ROleMak Fostiropoulos had been consultant to the Department of Physics at AUTh.