Ultrafast Photoconductivity and Terahertz Vibrational Dynamics in Double‐Helix SnIP Nanowires

• DOI: 10.1002/adma.202100978
• Publication Date: 2021-07-19T07:20:56Z
• Authors: David N. Purschke; Markus R. P. Piel...; Ebru Üzer; Claudia Ott; Charles Jensen; Annabelle Degg; Anna Vogel; Naaman Amer; Tom Nilges; Frank A. Hegmann
• Keywords: Photoconductivity; Helix (gastropod); Dynamics

Tin iodide phosphide (SnIP), an inorganic double-helix material, is a quasi-1D van der Waals semiconductor that shows promise in photocatalysis and flexible electronics. However, our understanding of the fundamental photophysics charge transport dynamics this new material limited. Here, we use time-resolved terahertz (THz) spectroscopy to probe transient photoconductivity SnIP nanowire films and, with insight into highly anisotropic electronic structure from quantum chemical calculations, measure electron mobility as high 280 $cm^2V^{-1}s^{-1}$. Additionally, THz vibrational spectrum reveals photoexcitation-induced redistribution reduces amplitude twisting mode outer SnI helix on picosecond timescales. Finally, show carrier lifetime are limited by trap density greater than $10^{18}\,cm^{-3}$. Our results provide optical excitation relaxation pathways demonstrate remarkably for such soft material.