TY - JOUR
T1 - From Cubic to Hexagonal
T2 - Electronic Trends across Metal Halide Perovskite Polytypes
AU - Li, Zhenzhu
AU - Park, Ji Sang
AU - Ganose, Alex M.
AU - Walsh, Aron
N1 - Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society
PY - 2023/7/6
Y1 - 2023/7/6
N2 - Polytypes formed during the growth of metal halide perovskites can give rise to the formation of face-sharing sequences in corner-sharing octahedral networks. Here, the electronic influences of such structures, including the 6H and 12R phases, are found to be correlated with the fraction and stacking sequence of the face-sharing layers. The band gaps of polytypes feature a characteristic evolution from indirect to direct from pure hexagonal (2H) to cubic (3C) phases. Rather than arising from orbital mixing at the atomic level, a large band gap bowing of 1.96 eV in the CsPbI3 family was attributed to the long-range electronic interaction between octahedral building blocks. While retaining a high carrier velocity (∼2 × 105 m s-1), Fermi surface analysis further revealed a decrease of dimensionality from 3D to 2D in frequently observed polytypes, indicating a carrier blocking and anisotropic transport effect of hexagonal impurity phases, with consequences for their applications in solar cells and other optoelectronic devices.
AB - Polytypes formed during the growth of metal halide perovskites can give rise to the formation of face-sharing sequences in corner-sharing octahedral networks. Here, the electronic influences of such structures, including the 6H and 12R phases, are found to be correlated with the fraction and stacking sequence of the face-sharing layers. The band gaps of polytypes feature a characteristic evolution from indirect to direct from pure hexagonal (2H) to cubic (3C) phases. Rather than arising from orbital mixing at the atomic level, a large band gap bowing of 1.96 eV in the CsPbI3 family was attributed to the long-range electronic interaction between octahedral building blocks. While retaining a high carrier velocity (∼2 × 105 m s-1), Fermi surface analysis further revealed a decrease of dimensionality from 3D to 2D in frequently observed polytypes, indicating a carrier blocking and anisotropic transport effect of hexagonal impurity phases, with consequences for their applications in solar cells and other optoelectronic devices.
UR - http://www.scopus.com/inward/record.url?scp=85164408009&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.3c01232
DO - 10.1021/acs.jpcc.3c01232
M3 - Article
AN - SCOPUS:85164408009
SN - 1932-7447
VL - 127
SP - 12695
EP - 12701
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 26
ER -