Electrochemical properties and optical response of cadmium selenide quantum dot film electrodes

In: Proceedings of the National Academy of Sciences of Belarus, Chemical Series, Band 57, Heft 2, S. 144-151

Abstract

Electrochemical charge/discharge mechanisms in the electrophoretically deposited CdSe quantum dot (QD)film electrodes in NBu4PF6 acetonitrile solution have been investigated. The films were deposited from CdSe colloidal solution in nitrobenzene at variable QD size (diameter) from 3.4 to 6.3 nm onto transparent conducting glass substrates. Electrochemical behavior and optical response were characterized by cyclic voltammetry (CV) and in situ absorption spectroscopy. Electrochemical charging under an inert gas atmosphere results in a reversible color change (electrochromism), due to the bleach of exciton absorption with 0.3 optical density changes. The mechanism of electrochemical charging comprises electron transfer from conducting substrate to QD, interparticle transfer and also electron capturing by acceptors in solution. The introduction of a strong electron acceptor (O2) into the solution results in a suppression of electrochromism. The influence of oxygen is rather reversible which is observed from recovered electrochromic behavior after electrolyte resaturation with argon.