Optoelectronic micro-
and nanostructures have a vast parameter
space to explore for modification and optimization of their functional
performance. This paper reports on a data-led approach using high-throughput
single nanostructure spectroscopy to probe >8000 structures, allowing
for holistic analysis of multiple material and optoelectronic parameters
with statistical confidence. The methodology is applied to surface-guided
CsPbBr
3
nanowires, which have complex and interrelated
geometric, structural, and electronic properties. Photoluminescence-based
measurements, studying both the surface and embedded interfaces, exploits
the natural inter nanowire geometric variation to show that increasing
the nanowire width reduces the optical bandgap, increases the recombination
rate in the nanowire bulk, and reduces the rate at the surface interface.
A model of carrier recombination and diffusion ascribes these trends
to carrier density and strain effects at the interfaces and self-consistently
retrieves values for carrier mobility, trap densities, bandgap, diffusion
length, and internal quantum efficiency. The model predicts parameter
trends, such as the variation of internal quantum efficiency with
width, which is confirmed by experimental verification. As this approach
requires minimal
a priori
information, it is widely
applicable to nano- and microscale materials.
By combining in situ optical spectroscopy with a high spatial resolution mass spectrometry, we directly link the evolution in carrier recombination processes in perovskite films to light-induced ion migration.
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