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
Group PhD student Hoyeon Choi has had a conference proceedings accepted for SPIE Europe 2020. As this conference has been cancelled, his talk is available throught the SPIE Digital Form.
In his work, Hoyeon describes the application of confocal and time-resolved spectral mapping to study and understand photobrightening and degradation processes in a prototypical perovskite material fabricated with and without use of anti-solvent treatment.
Reference: Spatially and temporally resolved degradation in antisolvent treated perovskite films, Hoyeon Choi, Chun-Ren Ke, Stefan Skalsky, Wendy Flavell, and Patrick Parkinson, Proc. SPIE 11365, Organic Electronics and Photonics: Fundamentals and Devices II, 113650Q
Patrick acted as external examiner for Tim Crothers, a student with Prof. Laura Herz in Physics at Oxford University. Tim defended his thesis on Charge-carrier transport and recombination dynamics in metal halide perovskites.
Congratulations to Ruben Ahumada-Lazo for his new paper on emission properties of perovskite nanocrystals. In his new paper, published in ACS Journal of Physical Chemistry C, he used ultrafast and high-fluence optical techniques based at the Photon Science Institute to reveal the radiative and non-radiative recombination pathways in CsPbCl3 perovskite nanocrystals.
In this collaboration between the Binks group (Manchester Physics), Parkinson group (Manchester Physics), the Ducati group (Cambridge Materials), and the Humphreys Group (Cambridge Materials), a combination of synthesis, electron microscopy, photoluminescence and transient absorption are combined to reveal exciton, biexciton and trion lifetimes.