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Professor Chris Blackman

 

Summary
 My work focuses on the use of vapour deposition techniques (chemical vapour deposition, atomic layer deposition) for synthesis of nanostructured and thin film materials for use in energy and gas sensing applications.
Summary of research group
 I collaborate with academic groups in the UK and Europe on programmes in materials synthesis, characterization and functional testing. I also work with industrial partners to develop intellectual property (US2012/0080092, WO2008/009967) by exploiting vapour synthesis methods for the manufacture of commercially relevant products.
Research highlights
 

Nanomaterial Synthesis and Characterisation

Correlation of Optical Properties, Electronic Structure, and Photocatalytic Activity in Nanostructured Tungsten Oxide

INVITED CONTRIBUTION to “Advances in Chemical Vapour Deposition” special issue (and front cover)

Materials_interface_2017

Min Ling, Christopher Blackman*, Robert Palgrave, Carlos Sotelo-Vazquez, Andreas Kafizas, Ivan Parkin, DOI: 10.1002/admi.201700064

Advanced Materials Interfaces: Volume: 4 Issue: 18 Page: 1700064 Published 2017

Here my group used our expertise in nanomaterial synthesis to deposit tungsten trioxide nanorod arrays and probed their electronic structure, defect chemistry, optical bandgap, and photocatalytic activity. The results showed that for maximum oxidative photocatalytic performance, tungsten oxide should be engineered such that the bandgap is widened relative to bulk WO3 which is surprising, but increases in the overpotential for oxidation reactions appear to more than offset the loss in photon absorption.

Growth mechanism of planar or nanorod structured tungsten oxide thin films deposited via aerosol assisted chemical vapour deposition (AACVD)

Min Ling, Christopher Blackman*, DOI: 10.1002/pssc.201510047

physica status solidi C: Volume 12 Issue 7 Pages: 869-877 Published 2015

PSSC_2015

In this paper we investigate the evolution of tungsten oxide nanostructures via a self-catalysed vapour/solid (VS) mechanism, and understand their formation as a competition between nucleation parallel to the substrate and growth perpendicular to the substrate. The relative rates of these two competing processes are affected by temperature of reaction, concentration of precursor and the nature of the precursor itself, and we describe a mathematical description that allows description of conditions to optimise growth of either polycrystalline (flat) or nanostructured films.

Single-Step Deposition of Au- and Pt-Nanoparticle-Functionalized Tungsten Oxide Nanoneedles Synthesized Via Aerosol-Assisted CVD, and Used for Fabrication of Selective Gas Microsensor Arrays

Stella Vallejos, Polona Umek, Toni Stoycheva, Fatima Annanouch, Eduard Llobet, Xavier Correig, Patrizia De Marco, Carla Bittencourt, Chris Blackman*, DOI: 10.1002/adfm.201201871

Advanced Functional Materials Volume: 23 Issue: 10 Pages: 1313-1322 Published: 2013

Fucntional_Materials_2013

This article describes an extension of my groups previously published method to encompass a wider matrix of nanomaterials. Here we use the differentiation provided by the matrix to form a selective gas sensor array. A crucial advance on our previous research was to demonstrate direct integration of our materials synthesis technique with micromachined gas sensor platforms, something which is not possible with traditional gas sensor processing techniques.

Au nanoparticle-functionalised WO3 nanoneedles and their application in high sensitivity gas sensor devices

INVITED CONTRIBUTION

Stella Vallejos, Toni Stoycheva, Polona Umek, Cristina Navio, Rony Snyders, Carla Bittencourt, Eduard Llobet, Christopher Blackman*, Savio Moniz, Xavier Correig, DOI: 10.1039/c0cc02398a

Chemical Communications Volume: 47 Issue: 1 Pages: 565-567 Published: 2011

This article described an entirely new method of making functionalized nanomaterials, featuring co-deposition of two precursors in the vapour phase to create a metal nanoparticle decorated nanostructured metal oxide. We characterized the materials for gas sensing properties in collaboration with the Spanish group. This type of material has very wide potential applications, particularly in the areas of gas sensing and energy materials, two key areas for my group.

 

Heterojunctions

Evidence and Effect of Photogenerated Charge Transfer for Enhanced Photocatalysis in WO3/TiO2 Heterojunction Films: A Computational and Experimental Study

Carlos Sotelo‐Vazquez, Raul Quesada‐Cabrera, Min Ling, David O. Scanlon, Andreas Kafizas, Pardeep Kumar Thakur, Tien‐Lin Lee, Alaric Taylor, Graeme W. Watson, Robert G. Palgrave, James R. Durrant, Christopher S. Blackman, Ivan P. Parkin*, DOI: 10.1002/adfm.201605413

Functional_Materials_2017

Advanced Functional Materials Volume: 27 Issue: 18 Page: 1605413 Published: 2017

Here my group synthesised tungsten oxide nanorod arrays, which were subsequently coated in a conformal layer of TiO2. This heterojunction showed an unusual electron transfer process, where photogenerated electrons moved from the WO3 layer into TiO2. State‐of‐the‐art hybrid density functional theory and hard X‐ray photoelectron spectroscopy were used to elucidate the electronic interaction at the WO3/TiO2 interface. Transient absorption spectroscopy showed that recombination was substantially reduced, extending both the lifetime and population of photogenerated charges into timescales relevant to most photocatalytic processes. This increased the photocatalytic efficiency of the material, which is among the highest ever reported for a thin film.

Aerosol-assisted CVD-grown PdO nanoparticle-decorated tungsten oxide nanoneedles extremely sensitive and selective to hydrogen

Fatima Annanouch, Zaidi Haddi, Min Ling, Francesco Di Maggio, Stella Vallejos, Toni Villic, Yiyun Zhu, Tahira Shujah, Polona Umek, Carla Bittencourt, Christopher Blackman*, Eduard Llobet*, DOI: 10.1021/acsami.6b00773

ACS Applied Materials and Interfaces: Volume: 8 Issue: 16 Pages: 10413-10421 Published 2016

This article describes a new approach to designing selective gas sensor materials, by creating a heterojunction in which one component is chemically reactive to a specified gas. Here my group carried out the synthesis of the nanostructured heterojunction for analysis as a sensing material by our partners in Spain. By decorating a bulk material with the chemically sensitive component a highly responsive and selective gas sensor material is prepared. This approach demonstrates the strategy my group is targeting for design of better sensor materials.

 

Complex Oxides

Visible-light driven water splitting over BiFeO3 photoanodes grown via the LPCVD reaction of [Bi(OtBu)3] and [Fe(OtBu)3]2 and enhanced with a surface nickel oxygen evolution catalyst

Savio Moniz, Christopher Blackman*, Paul Southern, Paul Weaver, Junwang Tang, Claire Carmalt, DOI: 10.1039/C5NR04804D

Nanoscale: Volume: 7 Issue: 39 Pages 16343-16353 Published 2015

This article describes a new CVD route to thin films of the complex oxide BiFeO3. This continued the work of my group in bismuth materials for energy applications, and here we demonstrated production of a photo-active films with high activity for oxygen evolution compared to competing methods of material production.

A simple, low-cost CVD route to thin films of BiFeO3 for efficient water photo-oxidation
‘HOT PAPER

Savio Moniz, Raul Quesada-Cabrera, Christopher Blackman*, Junwang Tang, Paul Southern, Paul Weaver, Claire Carmalt, DOI: 10.1039/c3ta14824f

Journal of Materials Chemistry A: Volume: 2 Issue: 9 Pages: 2922-2927 Published 2014

This article describes a simple new route to thin films of the complex oxide BiFeO3. Complex oxides are an area my group is actively pursuing across a number of areas, and here we demonstrated the approach by producing a photo-active film with high performance.

 

Atomic Layer Deposition

The effect of film thickness on the gas-sensing properties of ultra-thin TiO2 films deposited by atomic layer deposition

INVITED CONTRIBUTION

Rachel Wilson, Cristian Eugen Simion, Christopher Blackman*, Claire Carmalt, Adelina Stanoiu, Francesco Di Maggio, James Covington, DOI: 10.3390/s18030735

Sensors_2018

Sensors: Volume: 18 Issue: 3 Page 735 Published 2018

Analyte sensitivity for gas sensors based on semiconducting metal oxides should be highly dependent on the film thickness, particularly when that thickness is on the order of the Debye length. Here we prepared TiO2 thin films by atomic layer deposition (ALD) and the TiO2 films were exposed to different concentrations of CO, CH4, NO2, NH3 and SO2 to evaluate their gas sensitivities. These experiments showed that the TiO2 film thickness played a dominant role within the conduction mechanism.

Research Facilities
 We have a range of CVD reactors available for use, including spray, aerosol-assisted and low pressure, and we have two reactors dedicated for use in atomic layer deposition that are capable of depositing multiple metal precursors using a single oxidant source.
Awards
 PW Allen Award from The Chartered Society of Forensic Sciences (http://www.csofs.org/PW-Allen-Award)
Memberships
 Royal Society of Chemistry
Research interests
 
  • Chemical vapour deposition
  • Atomic layer deposition
  • Nanomaterials
  • Heterojunctions
  • Complex oxides
  • Gas sensing
  • Environmental monitoring
  • Photocatalysis
Teaching
 My interests are in the use of web-based resources for enhancing learning outcomes from traditional methods of
LAB_01
teaching at university level. I have worked with a software developer (Learnexx 3D) to develop 3D virtual lab simulations to be used in pre-lab preparation and a demo of the software can be found in the following link to the Learnexx simulation. This work has been acknowledged by a Provosts Teaching Award and a Faculty Teaching Award at UCL