The innovation engine for new materials

Brian Barraza


The University of Texas at El Paso



Faculty Sponsor(s): 

Anna J. Lehner
Ram Seshadri

Faculty Sponsor's Department(s): 


Project Title: 

Synthesis and Characterization of Model System Iodobismuthates for the Purpose of New Lead-Free Photovoltaic Materials

Project Description: 

The rapid increase in photovoltaic efficiencies in main group metal halide perovskites, such as (CH3NH3)PbI3, has sparked a recent interest in lead-free alternatives. The current work explores simple synthetic routes towards hybrid organic-inorganic bismuth iodides in order to define the effects of the crystal structure on the opto-electronic properties of these materials. Various complex heavy metal iodides were synthesized and then characterized through powder and single crystal X-ray diffraction, infrared, and UV/Vis spectroscopy. Band gap values for all three structures were determined using Tauc Plot transformations on the UV/Vis data collected. The band gaps where determined by evaluation of the UV/Vis spectra using Tauc plots. Single crystals of three compounds were grown through evaporation techniques. As the connectivity mode of the anionic units is determined by the nature and size of the organic cation, these compounds are excellent model systems for the rational design of new photovoltaic materials.