The development of heavy metal semiconductors is a growing field of interest for their application in photovoltaics, light emission, and radiation detection. This is due to their robust ability to convert incident photons of visible wavelength and high energy into charge current while remaining stable, optimizable, and readily synthesizable. As the field continues to expand there must also be expansion into new phases and chemistry that drive for the development of new technologies. Beginning from the heavy metal halide binaries, MIn (M = Pb, Bi; n = 2,3), and the ternary compounds inspired by the perovskites, AM’X3 (A = Cs, Rb; M’ = Ge, Sn, Pb; X = Cl, Br, I), an effort is made to modify their compositions to unveil new structures and properties by optical, structural, computational, and electrical analysis. From mixtures of 2D PbI2 and BiI3, the material (PbI2)1-x(BiI3)x ¬was synthesized, characterized and discovered to have remarkable conductance switching properties due to nanoscale phase separation and integration. PbI2)1-x(BiI3)x also displays unconventional, controllable optical properties where mid-gap states can promote below band gap absorption due to clustering of Bi within vacancy deficient phase boundaries. The modification of these binary mixtures with the addition of Cu1+ to results in the quaternary CuMBiI6 (M = Sn, Cd, Pb) phases synthesized and found to adopt defect abundant 3D structures promoting Cu ion conduction. Investigation of the substitution of Au for A-site cation in AMX3 yields black Au3+Pb2I7 where the low band gap is induced by Au-I ligand charge transfer. Overall, this dissertation exemplifies the use of exploratory synthesis for the discovery of new materials and their resulting properties.

Creator

• Alexander, Grant

DOI

• https://doi.org/10.21985/n2-apgs-7g27

Subject

• Inorganic chemistry

Language

• en

Alternate Identifier

• etdadmin_upload_710938
• http://dissertations.umi.com/northwestern:14958

Keyword

• Semiconductors
• Materials
• Conductance Switching

Date created

• 2019-01-01

Resource type

• Dissertation

Rights statement

• In Copyright