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! Or search: youtu.be/H8cvJfZq8S8 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.