Morphology, Electrical Conductivity, and Reactivity of Mixed Conductor CuBr Films:  Development of a New Ammonia Gas Detector

Abstract

The microstructure, electrical properties, aging, and electrolytic decomposition of sputtered CuBr films are described and discussed with respect to the defect chemistry of this mixed Cu+ ion−electron hole conductor. Ammonia gas adsorption increases the electrical resistance of the films. This effect can be used to design a new selective, sensitive, fast, and reversible ammonia gas sensor.

CuBr blue light emitting electroluminescent thin film devices

“…This process of metallic cathodic deposition is known as electrolytic decomposition and occurs when a polar material is subjected to a steady state source greater than its decomposition threshold. According to [7,13], the threshold voltage is a function of the combination of the thermodynamic decomposition voltage, which could be deduced from the Gibbs free energy of formation of CuBr (2CuBr → Cu + CuCl 2 ; ~ 0.7 V at atmospheric pressure), over voltages for different processes, including Ohmic drop, charge transfer at the electrodes and the nucleation of the electrodeposits. On the other hand there was no indication of electrolytic decomposition in the samples subjected to AC voltage stresses even for durations up to 3 hours as shown on Fig.…”

Solid-State Electrolysis in CuBr Thin Films: Observation and Modelling of Fractal Growth

“…A recent example is the preparation of CuBr films used in a sensitive and selective ammonia sensor. [4] One of the most versatile preparation techniques employed for materials with low electrical conductivity, radio-frequency sputtering, [5] allows extention of the accessible range of grain sizes towards the nanometer scale. Properties that are not observable in bulk materials are revealed in such materials with confined dimensions but undesirable effects, such as electromigration and electrolysis phenomena, may also be enhanced.…”

“…For example, protein conjugation steps are undertaken at extremely low particle concentrations in polymer-and surfactant-free solutions. [4] In contrast to aqueous synthetic protocols, organic synthetic methods produce particles with narrow dispersity and high concentrations. [2, 5±9] Therefore, procedures that allow the transfer of nanoparticulate materials from organic solvents to water have attracted much attention, particularly as metal nanoparticles in water are widely used in biolabelling [4,10] and in the construction of nanostructured films.…”

Chemosensitive properties of electrically conductive Cu(I) compounds at room temperature

“…This approach was realized by Lauque and co-workers [3][4][5] suggesting to use copper(I) bromide. The interactions between copper ions and NH 3 between the gas phase and the Cu + ion-conductor with modified concentrations of mobile copper atoms and copper vacancies.…”

“…This approach was realized by Lauque and co-workers [3][4][5] suggesting to use copper(I) bromide. The interactions between copper ions and NH 3 between the gas phase and the Cu + ion-conductor with modified concentrations of mobile copper atoms and copper vacancies. Recently some other copper(I)-ion-conductors were suggested for gas sensing, in particular cuprous oxide for the detection of nitrogen dioxide [6], ethanol [7] and hydrogen sulfide [8] and cuprous chloride for carbon monoxide [9].…”