TY - JOUR
T1 - Direct Gap Semiconductors Pb2BiS2I3, Sn2BiS2I3, and Sn2BiSI5
AU - Islam, Saiful M.
AU - Malliakas, Christos D.
AU - Sarma, Debajit
AU - Maloney, David C.
AU - Stoumpos, Constantinos C.
AU - Kontsevoi, Oleg Y.
AU - Freeman, Arthur J.
AU - Kanatzidis, Mercouri G.
N1 - Funding Information:
D.S. and S.M.I. acknowledge partial support from NSF Grant DMR-1410169, and O.Y.K. and A.J.F. (band structure calculations) are supported by DHS-ARI Grant 2014-DN-077-ARI086-01. We also acknowledge the MRSEC program (Grant NSF DMR-1121262) at the Materials Research Center for use of the facilities. SEM, EDS, and XPS analyses were performed at the EPIC facility of the NUANCE Center at Northwestern University, supported by NSF-NSEC, NSFMRSEC, Keck Foundation, the State of Illinois, and Northwestern University.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/10/25
Y1 - 2016/10/25
N2 - New quaternary thioiodides Pb2BiS2I3, Sn2BiS2I3, and Sn2BiSI5 have been synthesized by isothermal heating as well as chemical vapor transport. Pb2BiS2I3 and Sn2BiS2I3 crystallize in the space group, Cmcm, with unit cell parameters a = 4.3214 (9), b = 14.258 (3), and c = 16.488 (3) Å a = 4.2890 (6), b = 14.121(2), and c = 16.414 (3) Å, respectively. Sn2BiSI5 adopts a unique crystal structure that crystallizes in C2/m with cell parameters a = 14.175 (3), b = 4.3985 (9), c = 21.625 (4) Å, and β = 98.90(3)°. The crystal structures of Pb2BiS2I3 and Sn2BiS2I3 are strongly anisotropic and can be described as three-dimensional networks that are composed of parallel infinite ribbons of [M4S2I4] (M = Pb, Sn, Bi) running along the crystallographic c-axis. The crystal structure of Sn2BiSI5 is a homologue of the M2BiS2I3 (M = Pb, Sn) which has two successive ribbons of [M4S2I4] separated by two interstitial (Sn1-xBixI6) octahedral units. These compounds were characterized by scanning electron microscopy, differential thermal analysis, and X-ray photoelectron spectroscopy. Pb2SbS2I3, Pb2BiS2I3, "Pb2Sb1-xBixS2I3" (x ∼ 0.4), Sn2BiS2I3 and Sn2BiSI5 are highly resistive and exhibit electrical resistivities of 3.0 G cm, 100 M cm, 65 M cm, 1.2 M cm, and 34 M cm, respectively, at room temperature. Pb2BiS2I3, Sn2BiS2I3, Pb2SbS2I3, "Pb2Sb1-xBixS2I3" (x ∼ 0.4), and Sn2BiSI5 are semiconductors with bandgaps of 1.60, 1.22, 1.92, 1.66, and 1.32 eV, respectively. The electronic band structures of Pb2BiS2I3, Sn2BiS2I3, and Sn2BiSI5, calculated using density functional theory, show that all compounds are direct bandgap semiconductors.
AB - New quaternary thioiodides Pb2BiS2I3, Sn2BiS2I3, and Sn2BiSI5 have been synthesized by isothermal heating as well as chemical vapor transport. Pb2BiS2I3 and Sn2BiS2I3 crystallize in the space group, Cmcm, with unit cell parameters a = 4.3214 (9), b = 14.258 (3), and c = 16.488 (3) Å a = 4.2890 (6), b = 14.121(2), and c = 16.414 (3) Å, respectively. Sn2BiSI5 adopts a unique crystal structure that crystallizes in C2/m with cell parameters a = 14.175 (3), b = 4.3985 (9), c = 21.625 (4) Å, and β = 98.90(3)°. The crystal structures of Pb2BiS2I3 and Sn2BiS2I3 are strongly anisotropic and can be described as three-dimensional networks that are composed of parallel infinite ribbons of [M4S2I4] (M = Pb, Sn, Bi) running along the crystallographic c-axis. The crystal structure of Sn2BiSI5 is a homologue of the M2BiS2I3 (M = Pb, Sn) which has two successive ribbons of [M4S2I4] separated by two interstitial (Sn1-xBixI6) octahedral units. These compounds were characterized by scanning electron microscopy, differential thermal analysis, and X-ray photoelectron spectroscopy. Pb2SbS2I3, Pb2BiS2I3, "Pb2Sb1-xBixS2I3" (x ∼ 0.4), Sn2BiS2I3 and Sn2BiSI5 are highly resistive and exhibit electrical resistivities of 3.0 G cm, 100 M cm, 65 M cm, 1.2 M cm, and 34 M cm, respectively, at room temperature. Pb2BiS2I3, Sn2BiS2I3, Pb2SbS2I3, "Pb2Sb1-xBixS2I3" (x ∼ 0.4), and Sn2BiSI5 are semiconductors with bandgaps of 1.60, 1.22, 1.92, 1.66, and 1.32 eV, respectively. The electronic band structures of Pb2BiS2I3, Sn2BiS2I3, and Sn2BiSI5, calculated using density functional theory, show that all compounds are direct bandgap semiconductors.
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U2 - 10.1021/acs.chemmater.6b02691
DO - 10.1021/acs.chemmater.6b02691
M3 - Article
AN - SCOPUS:84992723811
SN - 0897-4756
VL - 28
SP - 7332
EP - 7343
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 20
ER -