Directional Charge Transport in Layered Two‐Dimensional Triazine‐Based Graphitic Carbon Nitride

Angew. Chem. Int. Ed. 2019, 58, 9394

: 10.1002/anie.201902314

Press release

Dr. Yu Noda, Dr. Christoph Merschjann, Dr. Ján Tarábek, Dr. Patrick Amsalem, Prof. Dr. Norbert Koch, Dr. Michael J. Bojdys

Triazine‐based graphitic carbon nitride (TGCN) is the most recent addition to the family of graphene‐type, two‐dimensional, and metal‐free materials. Although hailed as a promising low‐band‐gap semiconductor for electronic applications, so far, only its structure and optical properties have been known. Here, we combine direction‐dependent electrical measurements and time‐resolved optical spectroscopy to determine the macroscopic conductivity and microscopic charge‐carrier mobilities in this layered material “beyond graphene”. Electrical conductivity along the basal plane of TGCN is 65 times lower than through the stacked layers, as opposed to graphite. Furthermore, we develop a model for this charge‐transport behavior based on observed carrier dynamics and random‐walk simulations. Our combined methods provide a path towards intrinsic charge transport in a direction‐dependent layered semiconductor for applications in field‐effect transistors (FETs) and sensors.

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Functional carbon nitride materials — design strategies for electrochemical devices

Nature Reviews Materials 2, Article number: 17030 (2017)


Fabian K. Kessler, Yun Zheng, Dana Schwarz, Christoph Merschjann, Wolfgang Schnick, Xinchen Wang & Michael J. Bojdys


In the past decade, research in the field of artificial photosynthesis has shifted from simple, inorganic semiconductors to more abundant, polymeric materials. For example, polymeric carbon nitrides have emerged as promising materials for metal-free semiconductors and metal-free photocatalysts. Polymeric carbon nitride (melon) and related carbon nitride materials are desirable alternatives to industrially used catalysts because they are easily synthesized from abundant and inexpensive starting materials. Furthermore, these materials are chemically benign because they do not contain heavy metal ions, thereby facilitating handling and disposal. In this Review, we discuss the building blocks of carbon nitride materials and examine how strategies in synthesis, templating and post-processing translate from the molecular level to macroscopic properties, such as optical and electronic bandgap. Applications of carbon nitride materials in bulk heterojunctions, laser-patterned memory devices and energy storage devices indicate that photocatalytic overall water splitting on an industrial scale may be realized in the near future and reveal a new avenue of ‘post-silicon electronics’.

Boosting Visible-Light-Driven Photocatalytic Hydrogen Evolution with an Integrated Nickel Phosphide–Carbon Nitride System

A. Indra, A. Acharjya, P. W. Menezes, C. Merschjann, D. Hollmann, M. Schwarze, M. Aktas, A. Friedrich, S. Lochbrunner, A. Thomas, M. Driess,
Angew. Chem. Int. Ed. 2017, 56, 1653
DOI: 10.1002/anie.201611605

Solar light harvesting by photocatalytic H2 evolution from water could solve the problem of greenhouse gas emission from fossil fuels with alternative clean energy. However, the development of more efficient and robust catalytic systems remains a great challenge for the technological use on a large scale. Here we report the synthesis of a sol–gel prepared mesoporous graphitic carbon nitride (sg-CN) combined with nickel phosphide (Ni2P) which acts as a superior co-catalyst for efficient photocatalytic H2 evolution by visible light. This integrated system shows a much higher catalytic activity than the physical mixture of Ni2P and sg-CN or metallic nickel on sg-CN under similar conditions. Time-resolved photoluminescence and electron paramagnetic resonance (EPR) spectroscopic studies revealed that the enhanced carrier transfer at the Ni2P–sg-CN heterojunction is the prime source for improved activity.

Ultrafast kinetics of linkage isomerism in Na2[Fe(CN)5NO] aqueous solution revealed by time-resolved photoelectron spectroscopy

Azhr A. Raheem1,2,3, Martin Wilke1,2, Mario Borgwardt1,2, Nicholas Engel1,2, Sergey I. Bokarev4,a), Gilbert Grell4, Saadullah G. Aziz5, Oliver Kühn4, Igor Yu. Kiyan2, Christoph Merschjann1,2,b), and Emad F. Aziz1,2,6,c)

Structural Dynamics 4, 044031 (2017); doi:

The kinetics of ultrafast photoinduced structural changes in linkage isomers is investigated using Na2[Fe(CN)5NO] as a model complex. The buildup of the metastable side-on configuration of the NO ligand, as well as the electronic energy levels of ground, excited, and metastable states, has been revealed by means of time-resolved extreme UV (XUV) photoelectron spectroscopy in aqueous solution, aided by theoretical calculations. Evidence of a short-lived intermediate state in the isomerization process and its nature are discussed, finding that the complete isomerization process occurs in less than 240 fs after photoexcitation. pre-launch

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