maldonado.group

Research Interests

 

-Passivation of inorganic semiconductor surfaces for improved stability and electronic quality

-Conversion of solar energy into electricity and chemical fuels

-Chemical control of semiconductor/metal interfaces for chemical sensing and electronics

-Kinetics and mechanisms of charge-transfer reactions on electrode surfaces

-Ensembles of discrete, synthetically prepared, inorganic colloids/particles and bulk electrode materials

 

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Conversion of Solar Energy into Electricity/Chemical Fuels:

Our group is interested in systems that capture, convert, and store incident solar energy as chemical bond energy.  A crystalline semiconductor electrode immersed in water is one simple design for a solar-powered chemical fuel generator.  The figure on the left highlights the salient properties of a semiconductor photoelectrode.  In general, inorganic semiconductors strongly absorb photons with energies greater than the band gap, readily support energetically and spatially separated electrons and holes, and are natural platforms for heterogeneous electron transfer involving acceptors/donors in solution. 

For technologically relevant photoelectrochemical systems that use sunlight to drive H₂ evolution or CO₂ reduction, there is lack of semiconductor electrode materials that are simultaneously efficient, stable, and cost-effective.  Our group is working in this area on several fronts. 

 

 

our research projects

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  Surface Passivation of III-V Semiconductors

  We are exploring surface derivitization methods to improve the chemical stability and electrocatalytic activity of known inorganic semiconductor interfaces.  This work involves surface sensitive electronic and vibrational spectroscopic analyses as well as electrochemical and photoelectrochemical studies.
  

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  Synthesis and Study of Nitride Semiconductor Photoelectrode Materials

  We are working on synthesizing new ternary and quaternary semiconductor alloy materials and cataloging their photoelectrochemical properties.  In addition to spectroelectrochemical methods, these efforts include high temperature solid-phase transformation reactions and subsequent materials characterization.
  

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  Electron Transfer at Conducting Polymer Electrodes

  Thin films of organic semiconductors are attractive electronic materials due to their ease of preparation, comparatively low cost, and possible electrocatalytic activity for desireable electrochemical reactions.  Our group is interested in kinetic studies of heterogeneous charge transfer reactions at organic semiconductor/liquid junctions.