Congratulations to Helen Tunstall-Garcia whose first paper co-authored with Bethan Charles and Rachel Evans has been published in Advanced Photonics Research. Their review is entitled “The Role of Polyhedral Oligomeric Silsesquioxanes in Optical Applications”.

In this review the authors examine the use of polyhedral oligomeric silsesquioxanes (POSS) for photonic applications, such as sensing, bioimaging, and optoelectronic devices. They describe the benefits of POSS (including acting as a passivating agent and preventing lumophore aggregation) and explore potential areas for future development (including in LEDs and as templating molecules for upconversion applications).

The Role of Polyhedral Oligomeric Silsesquioxanes in Optical Applications, Helen Tunstall-Garcia, Bethan L. Charles, Rachel C. Evans, Advanced Photonics Research 2021, https://doi.org/10.1002/adpr.202000196

We are delighted to announce that Bethan has recently been invited to become a senior member at Hughes Hall, Cambridge, where she will be taking up the role of Research Associate within the college.

Bethan is also joint winner, with Jeremie Asselin, of this year’s Armourers and Brasiers Company post-doctoral prize within the Department of Materials Science and Metallurgy. Many congratulations Bethan!

New paper out in Energy and Environmental Science in collaboration with Michael Debije (Eindhoven) and Gianmarco Griffini (Milan). We make the case for treating luminescent solar concentrators (LSCs) as optical devices and outline experimental protocols for the standardisation of LSC characterisation to enable advancement of the field. Link

Rachel has been awarded an EPSRC New Horizons grant in collaboration with Kalai Saravanamuttu (McMaster University, Canada) to develop bio inspired luminescent photonic structures for indoor light harvesting. We’ll be recruiting for a PDRA post later in the year so watch this space.

Congratulations to Tom for his paper “Dual-Template Approach to Hierarchically Porous Polymer Membranes” which has just been published as a Hot Article in Materials Chemistry Frontiers and selected for the Inside Front Cover image.

This work investigated the use of two templates as part of the manufacture of poly(ethersulfone) membranes by the non-solvent induced phase separation method. Control membranes were produced using a surfactant as the only additive, to produce a morphology with a dense skin-layer above a layer of larger finger-like vertical pores. Upon addition of a second small molecule template the microstructure at the 1 μm scale shows a distinct change from a closed structure to an open, more fibrous morphology. The effects of this microstructural change on key membrane properties are studied, with a profound increase being observed on the water permeability, which is further raised by subsequent removal of the small molecule from the product membrane.

Dual-Template Approach to Hierarchically Porous Polymer Membranes, Thomas J.F. Southern & Rachel C.Evans, Materials Chemistry Frontiers 2020, https://doi.org/10.1039/D0QM00610F

Congratulations to former and current group members Camille, Judith and Elaine for their paper “Light-Responsive Self-Assembly of a Cationic Azobenzene Surfactant at High Concentration” which has just been accepted by Soft Matter.

They report the high-concentration and lyotropic liquid crystalline behaviour of trimethylammonium bromide azobenzene photosurfactants for the first time. These surfactants are often used in a variety of applications (DNA compaction, photofoaming, microfluidics) and have been studied at low concentration, but reports of their formation of lyotropic liquid crystals remain rare.

Using polarised optical microscopy and small-angle X-ray scattering, self-assembled structures with long-range order and optical anisotropy are found for the trans-isomer. These structures are lost or disrupted with UV light irradiation and photoisomerisation to the cis-isomer.

The work was carried out using X-ray beamtime at Diamond Light Source.

Congratulations to Tom Southern, a final year PhD student in our group , who has been awarded a postgraduate teaching award by Fitzwilliam College. Well done Tom!

Congratulations to Kieran Richards, a second year PhD student in the group who won a prize for his talk at the UK Colloids 2020 Online Flash Presentations meeting on 20th July. Kieran presented his brand new work on the use of computer vision to analyse Pickering emulsions that he has developed during lockdown!

Congratulations to ex-group members Barry McKenna and Abhinav Shivkumar, and current group member Bethan Charles for their new paper, which has just been published in Nanoscale.

The stability and reproducibility of perovskite nanocrystals (PNC) produced by ligand-assisted reprecipitation (LARP) is investigated. Significant differences in optical properties and morphology are observed depending on specific synthetic factors. These differences can have profound effects on the resulting emission and stability of PNCs, although this is rarely reported in the literature. However, this information is important for new researchers entering a competitive field as well as in the drive to develop realistic pathways to scale-up synthesis. Therefore, we systematically examine (1) the effect of dilution of the parent dispersion, (2) choice of the halide source and ratio and (3) choice of capping ligand concentration in PNC synthesis.

Synthetic Factors affecting the Stability of Methylammonium Lead Halide
Perovskite Nanocrystals, Barry McKenna, Abhinav Shivkumar, Bethan Charles and Rachel C. Evans*, Nanoscale, 2020, Advance Article.

Congratulations to Abi Collins, Thomas Southern, Morton Lyu and Mike Bennison whose SPIE Proceedings manuscript entitled Photoactive organic-inorganic hybrid polymer waveguides for optical device technologies from the Photosensitive Materials and their Applications Conference has been published.

This work reports on the mechanical and optical properties of low molecular weight ureasils and the relationship between the molecular weight of their precursors and these properties. An array of techniques including steady-state photoluminescence and Fourier-transform infrared spectroscopy, 4-point flexural testing, and uniaxial tensile testing are used.

A relationship was observed between the flexural and elastic moduli of these ureasils and their molecular weight. The presence of unbound urea in samples was related to their water contact angle and stiffness. These relationships can be used to develop waveguide materials with tunable properties.

Abigail Collins, Thomas Southern, Guanpeng Lyu, Michael J. Bennison, Rachel C. Evans, Photoactive organic-inorganic hybrid polymer waveguides for optical device technologies. Invited paper, 11367-32, SPIE Photonics Europe Digital Forum, 2020.