Use of nanocrystal thin films as active layers in optoelectronic devices requires tailoring of their electronic band structure, often through graded and heterojunction structures. Here, we demonstrate energy-resolved electrochemical impedance spectroscopy (ER-EIS) and open-circuit voltage measurements as a method to quantify electronic structure and Fermi-level position in nanocrystal (NC) thin films. Unlike vacuum-based techniques for quantifying electronic structure, these electrochemical based techniques are well-suited for nanocrystal-based thin films as they allow for <i>in-situ</i> assessment of electronic structure during the solution-based fabrication of the thin film. Using well-studied lead sulfide nanocrystals as an example, we probe the energy position and number density of defect or dopant states as well as the modification of energy levels in nanocrystal solids that results through the exchange of surface ligands. These sensitive and fast methods to measure the electronic structure of nanostructured thin films under fabrication conditions provide insights into existing device operation and paths for further optimization in optoelectronic devices.

<i>In-situ</i> measuring the electronic structure of nanocrystal thin films using energy-resolved electrochemical impedance spectroscopy

256th National Meeting (2018)

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In-situ measuring the electronic structure of nanocrystal thin films using energy-resolved electrochemical impedance spectroscopy