New Paper: Carrier dynamics and recombination mechanisms in InP twinning superlattice nanowires

(a) Twinning superlattice nanowire on substrate, (b) high-resolution SEM and (c) TEM image showing superlattice.

A new paper has been published in Optics Express, led by collaborator Xiaoming Yuan at Central South University (Changsha) and growth colleagues in the group of Prof. Jagadish at Australian National University.

In this work, novel “twinning-superlattice” nanowires are grown. Once passivated, this growth method produces extremely high quality nanowires, with carrier lifetimes of over 7ns. This work made use of the Manchester iTCSPC spectrometer, built by group PhD student Stefan Skalsky to study the low fluence dynamics at room temperture.

This growth method opens up a new facet in crystal-phase engineering for nanowire optoelectronics.

Reference: Carrier dynamics and recombination mechanisms in InP twinning superlattice nanowires, Xiaoming Yuan, Kunwu Liu, Stefan Skalsky, Patrick Parkinson, Long Fang, Jun He, Hark Hoe Tan, and Chennupati Jagadish, Optics Express 28, 16795 (2020) DOI: 10.1364/OE.388518

New Paper: Visualizing the role of photoinduced ion migration on photoluminescence in halide perovskite grains​

Group student Hoyeon has had a paper accepted in the RSC Journal of Materials Chemistry C, studying the photo-brightening effect in perovskite grains using correlated optical and chemical mapping. In collaboration with the Flavell group and the NanoSIMS group at Manchester, this study linked luminescence lifetime and emission energies to local changes in oxygen and iodine density close to the surface of methyammonium lead iodide grains; a prototypical next-generation photovoltaic material.

This new study unambiguously links the emission efficiency improvement under illumination – the so-called photo-brightening effect – to light-induced migration of iodine into the bulk of the crystal and an increase in oxygen levels close to the surface of the grains. By mapping the emission efficiency and chemical levels on the sub-micron scale, we find that grain size has a decreasing role with light-soaking.

Reference: “Visualizing the role of photoinduced ion migration on photoluminescence in halide perovskite grains​“, J. Mater. Chem. C (2020), DOI:10.1039/d0tc01441a