In Situ Techniques for Monitoring Electrochromism An Advanced Laboratory Experiment

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Sarıçayır H. , Üce M. , Koca A.

JOURNAL OF CHEMICAL EDUCATION, cilt.87, ss.205-207, 2010 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 87
  • Basım Tarihi: 2010
  • Doi Numarası: 10.1021/ed800048u
  • Sayfa Sayıları: ss.205-207


The most common in situ technique used in science

laboratories is in situ spectroelectrochemistry, which focuses

primarily on the changes of transmission or absorption spectra

during the electrochemical perturbations of a system. Published

practical examples teaching the principles and applications of in

situ spectroelectrochemistry are limited (1, 2). Heineman (1)

developed several commonly used spectroelectrochemical methods

with examples of typical applications. He also developed an

electrochemical experiment describing analysis of an optically

transparent thin-layer electrode with a spectroelectrochemistry

technique (3). Similarly, there are few publications on the

teaching of the application of spectroelectrochemistry for optical

and electrochemical characterization of different electrochromic

materials (4-6). Color changes in these studies were observed by

the naked eye or proposed by spectral changes. It has been

suggested that to describe a particular color, its scientific parameters

must be identified because full-color characterization of

an electrochromic system is essential for its application. For this

purpose, an instrumental colorimetric measurement must be

applied to record the chromaticity diagram and color parameters

of a system.

The combination of reaction-oriented electrochemistry

with colorimetry in in situ electrocolorimetry allows for a more

complete analysis of electrochromic materials. While the technique

has been well developed during the last few decades, its

application in various fields of chemistry has only recently

become more widespread (7-9). There is no published practical

example of teaching the principles and applications of in situ

electrocolorimetry techniques. Thus, we developed an experiment

that characterizes the electrochromism of methyl viologen,

extensively investigated as a material for digital displays and smart

windows applications (10, 11). In this experimental procedure,

we describe the principles and applications of in situ electrocolorimetry

combined with in situ spectroelectrochemistry.

This experiment, accomplished in a 5 h laboratory period, is

one of a series of graduating-project experiments assigned to

fourth-year undergraduates in the chemical engineering department.

Each fourth-year undergraduate of our department is

required to prepare an experimental graduating project consisting

of advanced research-like experiments to improve his or her

literature skill, independent study ability, and understanding of

basic scientific research prior to the graduation-thesis program.

Depending on class size, available resources, and run-times,

this experiment can be performed as a demonstration experiment

or an experiment in the instrumental analysis or physical

chemistry lab.