All posts by MJB

Michael J. Bojdys joined the Charles University in Prague (Czech Republic) in 2014 as an Assistant Professor. His current research interest lies in the field of functional nanomaterials for semiconductor applications, gas storage and catalysis. Previously, Michael was holder of a research fellowship of the German Academic Exchange Service (DAAD) at the Technische Universität Berlin (Germany). He worked as a postdoctoral researcher at the University of Liverpool (UK) from 2010 to 2013. He completed his PhD thesis between 2006 and 2009 "On new allotropes and nanostructures of carbon nitrides" at the Max Planck Institute of Colloids and Interfaces in Potsdam (Germany). In 2006 he graduated as Master of Natural Sciences at the University of Cambridge (UK).

One-pot synthesis of high-capacity silicon anodes via on-copper growth of a semiconducting, porous polymer

Huang, J.; Martin, A.; Urbanski, A.; Kulkarni, R.; Amsalem, P.; Exner, M.; Li, G.; Müller, J.; Burmeister, D.; Koch, N.; Brezesinski, T.; Pinna, N.; Uhlmann, P.; Bojdys,* M. J. Nat. Sci. 2022. DOI: 10.1002/ntls.20210105 & ChemRxiv 2022. DOI: 10.26434/chemrxiv-2021-jmrvw-v3

[Press-release] IDW-online “Neue Produktionsmethode für flexible, langlebige Anoden mit hoher Kapazität im Verhältnis zum Gewicht”

Key Points

  • We present a Si-based anode with superior-performance close to the limits of theoretical capacities with an advantage of factor ×10 over any hitherto produced, commercial electrode system.
  • Our electrodes sustain physical bending without surface reconstruction or crack formation, and heat shocks without loss of capacity and overall cycling performance.
  • The critical, novelty that enables the extraordinary performance increase and durability of our anodes is a class of semi-conducting porous organic polymers that replaces all conventional additives in battery ink formulations.

Size Effects of the Anions in the Ionothermal Synthesis of Carbon Nitride Materials

Burmeister, D.; Müller, J.; Plaickner, J.; Kochovski, Z.; List-Kratochvil, E. J. W.; Bojdys,* M. J. Chem. Eur. J. 2022. DOI: 10.1002/chem.202200705; Zenodo 2022. DOI: 10.5281/zenodo.6244965

Ionothermal condensation of dicyandiamide in alkali halide salt melts leads to the formation of extended 2D, layered frameworks only in the presence of small halides such as chloride, and bromide. With increasing size of the alkali halide intercalate, stabilizing van der Waals interactions between extended, π-conjugated triazine-based sheets are lost. We identify the main, crystalline product from an alkali iodide eutectic as melem hydrate, a heptazine (C6N7)-based, hydrogen-bonded, monoclinic solid.

Ukraine: how can the scientific community help scholars at risk?

Scientists engage in advocacy efforts to organize and accelerate humanitarian responses, academic exchange, funding, hiring, accommodation, and preserving physical and digital academic assets in Ukraine. What can you do as a scientist to #StandWithScholarsAtRisk? We have summarized the experiences of the Young Scientists at the WEF as “academic ambassadors” and offer pathways for leveraging the international science community and inspire action.

WEF Agenda:

Interview [in German] – Wie die Wissenschaftscommunity geflüchteten Wissenschaftler:innen helfen kann

Interview [in English] – How the science community can help refugee scientists

The missing link of science in policy – 1M scientists and 100M hours could be part of the answer

“For science to become an integral part of policymaking, we need a culture of engagement. Researchers need to be recognized and rewarded for developing and using this engagement,” reads the call of the Young Scientists at the World Economic Forum published in the Frontiers Policy Labs open access blog.

The intitative is supported by 52 signatories all former and current young World Economic Forum scientists from around the world – including bojdysLAB – who believe that this could trigger a domino effect and that more scientific knowledge from other fields would get into the hands of policymakers to inform their decisions.

This initiative has been highlighten by Jan-Martin Wiarda in “Most disaster movies start with scientists whose warnings are ignored by policymakers”.

Optimized synthesis of solution-processable crystalline poly(triazine imide) with minimized defects for OLED application

Burmeister, D.; Tran, H. A.; Müller, J.; Guerrini, M.; Cocchi, C.; Plaickner J.; Kochovski, Z.: List-Kratochvil, E.; Bojdys,* M. J. Angew. Chem. Int. Ed. 2021. DOI: 10.1002/anie.202111749 [OPEN ACCESS]

Crystalline semiconducting carbon nitrides are chemically and physically resilient, consist of earth abundant elements, and can be exfoliated into 2D atomically thin layers. In particular, poly(triazine imide) (PTI) is a highly crystalline semiconductor, and though no techniques exist to date that enable synthesis of macroscopic monolayers of PTI, it is possible to study it in thin layer device applications that are compatible with its polycrystalline, nanoscale morphology. In our study, we find that the by-product of conventional PTI synthesis is a C-C carbon rich phase that is detrimental for charge transport and photoluminescence. An optimised synthetic protocol yields a PTI material with an increased quantum yield, enabled photocurrent and electroluminescence. In addition, we report that protonation of the PTI structure happens preferentially at the pyridinic nitrogen atoms of the triazine (C3N3) rings, is accompanied by exfoliation of PTI layers, and contributes to increases in quantum yield and exciton lifetimes. This study describes structure-property relationships in PTI that link (i) the nature of defects, their formation, and how to avoid them with (ii) the optical and electronic performance of PTI. On the basis of our findings, we create an OLED prototype with PTI as the active, metal-free material, and we lay the foundations for device integration of solution-processable graphitic carbon nitride dispersions in semiconductor devices.

Press-releases: [IRIS, EN], [IRIS, DE], [KCL, EN], [HU, DE]

DOI: 10.1002/anie.202111749

Direct growth of crystalline triazine-based graphdiyne using surface-assisted deprotection-polymerisation

Kulkarni, R.; Huang, J.; Trunk, M.; Burmeister, D.; Amsalem, P.; Müller, J.; Martin, A.; Koch, N.; Kass, D.; Bojdys,* M. J. Chem. Sci. 2021. DOI: 10.1039/D1SC03390E [OPEN ACCESS]

Graphdiyne polymers have interesting electronic properties due to their π-conjugated structure and modular composition. Most of the known synthetic pathways for graphdiyne polymers yield amorphous solids because the irreversible formation of carbon-carbon bonds proceeds under kinetic control and because of defects introduced by the inherent chemical lability of terminal alkyne bonds in the monomers. Here, we present a one-pot surface-assisted deprotection/polymerisation protocol for the synthesis of crystalline graphdiynes over a copper surface starting with stable trimethylsilylated alkyne monomers. In comparison to conventional polymerisation protocols, our method yields large-area crystalline thin graphdiyne films and, at the same time, minimises detrimental effects on the monomers like oxidation or cyclotrimerisation side reactions typically associated with terminal alkynes. A detailed study of the reaction mechanism reveals that the deprotection and polymerisation of the monomer is promoted by Cu(II) oxide/hydroxide species on the as-received copper surface. These findings pave the way for the scalable synthesis of crystalline graphdiyne-based materials as cohesive thin films.

DOI: 10.1039/D1SC03390E

Development of metal-free layered semiconductors for 2D organic field-effect transistors

Burmeister, D.; Trunk, M. G.; Bojdys,* M. J. Chem. Soc. Rev. 2021. DOI: 10.1039/d1cs00497b [OPEN ACCESS]

Metal-free 2D covalent organic materials transport charges along and in-between π-conjugated layers. Here, we look at the prospects of graphitic carbon nitrides and covalent organic frameworks as 2D semiconductors “beyond graphene and silicon”.

DOI: 10.1039/d1cs00497b