Volk Sebastian, Yazdani Nuri, Sanusoglu Emir, Yarema Olesya, Yarema Maksym, Wood Vanessa
Department of Information Technology and Electrical Engineering , ETH Zurich , Gloriastrasse 35 , 8092 Zurich , Switzerland.
J Phys Chem Lett. 2018 Mar 15;9(6):1384-1392. doi: 10.1021/acs.jpclett.8b00109. Epub 2018 Mar 7.
Use of nanocrystal thin films as active layers in optoelectronic devices requires tailoring of their electronic band structure. Here, we demonstrate energy-resolved electrochemical impedance spectroscopy (ER-EIS) as a method to quantify the electronic structure in nanocrystal thin films. This technique is particularly well-suited for nanocrystal-based thin films as it allows for in situ assessment of electronic structure during solution-based deposition of the thin film. Using well-studied lead sulfide nanocrystals as an example, we show that ER-EIS can be used to 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. This work highlights that ER-EIS is a sensitive and fast method to measure the electronic structure of nanocrystal thin films and enables their optimization in optoelectronic devices.
将纳米晶体薄膜用作光电器件的活性层需要调整其电子能带结构。在此，我们展示了能量分辨电化学阻抗谱（ER-EIS）作为一种量化纳米晶体薄膜中电子结构的方法。该技术特别适用于基于纳米晶体的薄膜，因为它允许在基于溶液的薄膜沉积过程中对电子结构进行原位评估。以研究充分的硫化铅纳米晶体为例，我们表明ER-EIS可用于探测缺陷或掺杂剂态的能量位置和数密度，以及通过表面配体交换导致的纳米晶体固体中能级的变化。这项工作突出表明，ER-EIS是一种测量纳米晶体薄膜电子结构的灵敏且快速的方法，并能够在光电器件中对其进行优化。
