Viva in Cambridge

Patrick was the external examiner for Limeng Ni, a PhD student in the group of Akshay Rao at the University of Cambridge. Limeng was examined on her thesis exploring energy transfer in 2D perovskite materials, nanoparticles, and lanthenide-containing materials with a focus on singlet fission and triplet-triplet annihilation.

New Paper – Effect of size on the luminescent efficiency of perovskite nanocrystals

A new paper led by groups at Cambridge has been published in ACS Applied Energy Materials. In this work, a combination of nanoscale cathodoluminescence and time- and energy-resolved photoluminescence is used to reveal energy dynamics in colloidal perovskite nanocrystals. These techniques relate trap density and Auger effects to stoichiometry and size, providing a new route to optimization of these new materials.

In this study, group student Arturo carried out and prepare power dependant photoluminescence studies using tools in our group.

(a) ADF-STEM imagery of mixed colloidal perovskite nanocrstals along with (b) EELS and (c) Nano-cathodoluminescence.

Reference: “Effect of size on the luminescent efficiency of perovskite nanocrystals”, Griffiths et al., ACS Applied Energy Materials, 2019, DOI: 10.1021/acsaem.8b02132

Welcome to Tom Flavell

A welcome to Tom Flavell, a new PhD student in Physics who is primarily supervised by Prof. Wendy Flavell (no relation) and co-supervised by Patrick and Dr Andrew Thomas. Tom will be working on perovskite quantum dots, and will make use of the low-light spectroscopy facilities based in the OMS group.

New Paper – Threshold reduction and yield improvement of semiconductor nanowire lasers via processing-related end-facet optimization

Arturo has had a paper accepted for publication in Nanoscale Advances, describing the impact of the transfer process on the morphology and threshold of semiconductor nanowire lasers.

While many studies have sought to improve the threshold for lasing in semiconductor nanowire lasers, the role of process has not been significantly considered. By applying a large-scale population study to this system, Arturo has used statistical tools to identify the optimal processing methods which is transferrable to a wide varity of nanowire laser structures.

(Left) Threshold as a function of processing conditions, showing the improvement arising from PDMS or ultrasound transfer. (Right) A typical laser, showing coherent emission and lasing onset.

Reference: “Threshold reduction and yield improvement of semiconductor nanowire lasers via processing-related end-facet optimization“, J. A. Alanis et al., Nanoscale Advances, 2019 (10.1039/C9NA00479C)

Workshop on Perovskites and Emerging Optoelectronic Materials

Thanks to all of the speakers and attendees who came to the Workshop on Perovskites and Emerging Optoelectronic Materials , hosted in the Photon Science Institute. We heard from 8 speakers covering physics, materials and electronic engineering for photovoltaic and light-emitting applications.

Around 40 attendees at the Workshop, including professors, PDRAs, PhD students and undergraduates.
Lunch proved popular

The workshop was concluded with a seminar presentation from Dr. Becky Milot (University of Warwick), who spoke on “Optoelectronic Properties of Hybrid Metal Halide Perovskites”