Semiconductors based on bismuth halides have gained attention for a wide range of electronic applications, including photovoltaics, light-emitting diodes, and radiation detectors. Their appeal is due to their low toxicity, high environmental stability under ambient conditions, and easy processability by a wide range of scalable methods. The performance of Bi-based semiconductors is dictated by electron-phonon interactions, which limit carrier mobilities and can also influence optoelectronic performance, for example, by giving rise to a large Stokes shift for photoluminescence, unavoidable energy loss channels, or shallow optical absorption onsets. In this Perspective, we discuss the recent understanding of how polarons and self-trapped excitons/carriers form in Bi-based semiconductors (particularly for the case of Cs2AgBiBr6), their impact on the optoelectronic properties of the materials, and the consequences on device performance. Finally, we discuss the opportunities that control of electron-phonon coupling enables, including stable solid-state white lighting, and the possibilities of exploiting the strong coupling found in bipolarons for quantum technologies.
Bibliographical noteFunding Information:
S.R.R. and R.L.Z.H. would like to thank the Engineering and Physical Sciences Research Council (EPSRC; Grant No. EP/ V014498/1). R.A.J. acknowledges support from a DTP studentship from EPSRC (Grant No. EP/N509620/1). R.A.J. and J.L.M.-D. would like to thank Bill Welland for financial support, as well as the Winton Programme for the Physics of Sustainability through the Pump-Prime scheme. J.L.M.-D. acknowledges support from the Royal Academy of Engineering Chair in Emerging Technologies (Grant No. CIET1819_24). R.L.Z.H. would like to thank the Royal Academy of Engineering through the Research Fellowships scheme (No. RF\201718\1701). AUTHOR DECLARATIONS Conflict of Interest The authors declare no conflicts of interest. DATA AVAILABILITY Data sharing is not applicable to this article as no new data were created or analyzed in this study.
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)