TY - JOUR
T1 - Dynamic Disorder, Band Gap Widening, and Persistent Near-IR Photoluminescence up to at Least 523 K in ASnI3 Perovskites (A = Cs+, CH3NH3
+ and NH2-CHNH2
+)
AU - Kontos, Athanassios G.
AU - Kaltzoglou, Andreas
AU - Arfanis, Michalis K.
AU - McCall, Kyle M.
AU - Stoumpos, Constantinos C.
AU - Wessels, Bruce W.
AU - Falaras, Polycarpos
AU - Kanatzidis, Mercouri G
PY - 2018/11/21
Y1 - 2018/11/21
N2 - We report temperature-dependent photoluminescence (PL) in polycrystalline ASnI3 perovskites (A = Cs+, CH3NH3
+, and HC(NH2)2
+), demonstrating extremely robust emission up to very high temperatures (523 K for CsSnI3). The PL peak energy (EPL) monotonically blueshifts with increasing temperature, indicating band gap widening. Variable temperature synchrotron powder X-ray diffraction analysis confirms that these changes are associated with progressive emphanitic off-centering and dynamic fluctuations of the perovskite lattice. In CsSnI3, three different temperature gradients of EPL are defined (0.29 meV K-1 below 200 K, 0.17 meV K-1 from 200 to 400 K, and 0.48 meV K-1 above 400 K), commensurate with the onset of dynamic structural disorder at 200 K and its saturation at 400 K as the Cs+ atoms rattle independently of the [SnI3]- perovskite lattice. These results explain how solution-processed perovskites with massive defect concentrations can yield high optoelectronic performance at elevated temperatures.
AB - We report temperature-dependent photoluminescence (PL) in polycrystalline ASnI3 perovskites (A = Cs+, CH3NH3
+, and HC(NH2)2
+), demonstrating extremely robust emission up to very high temperatures (523 K for CsSnI3). The PL peak energy (EPL) monotonically blueshifts with increasing temperature, indicating band gap widening. Variable temperature synchrotron powder X-ray diffraction analysis confirms that these changes are associated with progressive emphanitic off-centering and dynamic fluctuations of the perovskite lattice. In CsSnI3, three different temperature gradients of EPL are defined (0.29 meV K-1 below 200 K, 0.17 meV K-1 from 200 to 400 K, and 0.48 meV K-1 above 400 K), commensurate with the onset of dynamic structural disorder at 200 K and its saturation at 400 K as the Cs+ atoms rattle independently of the [SnI3]- perovskite lattice. These results explain how solution-processed perovskites with massive defect concentrations can yield high optoelectronic performance at elevated temperatures.
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U2 - 10.1021/acs.jpcc.8b10218
DO - 10.1021/acs.jpcc.8b10218
M3 - Article
AN - SCOPUS:85057165316
VL - 122
SP - 26353
EP - 26361
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 46
ER -