Hidden Spontaneous Polarisation in the Sn2SbS2I3 Chalcohalide Absorber (Poster)

My UCL Chemistry 2nd Year PhD Poster.
YouTube talk here: https://youtu.be/H8cvJfZq8S8

Open-access Materials Horizons paper at: https://doi.org/10.1039/D1MH00764E

If you're interested in this work, please check out our open-access review on perovskite-inspired materials and defect tolerance here:
https://iopscience.iop.org/article/10.1088/1361-6528/abcf6d

For other research articles see:
https://bit.ly/3pBMxOG

For other talks on YouTube see:
https://bit.ly/2U5YgLf

Transcript

1. Hidden Spontaneous
   Polarisation in the Sn2
   SbS2
   I3
   Chalcohalide Solar Absorber
   Seán
   Kavanagh
   Perovskite-inspired materials (PIMs) aim to replicate the
   optoelectronic performance of lead-halide perovskites,
   while eliminating issues with stability and toxicity.
   Solution-grown tin-antimony sulfoiodide (Sn2
   SbS2
   I3
   ) solar
   cells, have recently emerged as promising PIMs, exhibiting
   power conversion efficiencies above 4% in the first
   experimental attempt (exceeding the first reported value
   for MAPI).
   We reveal the reported centrosymmetric Cmcm crystal
   structure to in fact represent an average over multiple
   polar Cmc21
   configurations, confirmed through a
   combination of lattice dynamics and molecular dynamics
   simulations.
   We predict a large spontaneous polarisation of 37 μC/cm2
   that could be active for electron-hole separation in
   operating solar cells. We further assess the radiative
   efficiency limit of this material, calculating ηmax
   > 30% for
   film thicknesses t > 0.5 μm.
   Scan me with your phone for a 10
   min YouTube talk on this work!
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   10−8 10−7 10−6 10−5 10−4 10−3
   Film Thickness (m)
   0
   10
   20
   30
   Max PV Efficiency (ηMax
   ) / %
   SLME
   Blank et al, Lambertian Scatterer
   Blank et al, Flat Scatterer @Kavanagh_Sean_
   sean.kavanagh.19@ucl.ac.uk
   a
   b
   c
   a Green arrows depicting spontaneous symmetry breaking and
   concomitant lattice polarisation in Sn2
   SbS2
   I3
   , with the resulting built-
   in potential (aiding electron-hole separation) shown alongside.
   b Variation of Sb–S bond lengths in Sn2
   SbS2
   I3
   during molecular
   dynamics simulations, demonstrating polarisation stability at room
   temperature (300 K) and breakdown at T = 500 K.
   c Maximum solar photovoltaic efficiency (ηmax
   ) vs film thickness.
   

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