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Title: Direct Evidence of Exciton–Exciton Annihilation in Single-Crystalline Organic Metal Halide Nanotube Assemblies
Award ID(s):
1709116 1664661
NSF-PAR ID:
10057955
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
The Journal of Physical Chemistry Letters
Volume:
9
Issue:
9
ISSN:
1948-7185
Page Range / eLocation ID:
2164 to 2169
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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  2. Abstract

    Aside from band gap reduction, little is understood about the effect of the tin‐for‐lead substitution on the fundamental optical and optoelectronic properties of metal halide perovskites (MHPs), especially when transitioning from 3D to lower dimensional structures. Herein, we take advantage of the spectroscopic isolation of excitons in 2D MHPs to study the intrinsic differences between lead and tin MHPs. The exciton's spectral fine structure indicates a larger polaron binding energy in tin MHPs. Additionally, the electroabsorption responses of the 2D MHPs demonstrates that tin MHPs have exciton binding energies 1.5–2× lower than that of their lead counterparts. Despite the lower binding energy, the excitons in tin MHPs are more Frenkel‐like with small radii, small polarizabilities, and large dipole moments. These results are interpreted as consequences of small polaron formation and disorder‐induced dipole moments. This work highlights the wide range of intrinsic differences between lead and tin MHPs as well as the complexity of excited states in these systems.

     
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