Photoelectrochemical passivation of undoped n-InP by ultra-thin polyphosphazene film: Towards a perfect photoanode? - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Electrochimica Acta Année : 2023

Photoelectrochemical passivation of undoped n-InP by ultra-thin polyphosphazene film: Towards a perfect photoanode?

A. M. Gonçalves
C. Njel
Mathieu Frégnaux
A. Etcheberry

Résumé

For the first time, the photoanodic behavior of undoped n-InP (≈ 1015 atoms.cm−3) is studied in liquid ammonia at low temperature (-55 °C) under atmospheric pressure. Under illumination, the low doping level provides unique conditions to monitor charge transfer at the interface since only photo-generated holes are involved in the passivation mechanism. Specific photoanodic transient phenomena are observed due to the photo-holes availability at the interface which depends on light intensity. Cycle voltammograms differ strongly from the initial ones in the dark. Photo-electrochemical transformations of InP responses are followed by cycle voltammetry for two conditions of illumination; under low and high luminous flux intensity. In spite of a pure photo-holes process for both cases, voltammograms are highly dependent on light intensity while impedance measurements present the same strong modifications. One-volt positive shift of the flat band potential is indeed observed. However, whatever is the luminous flux intensity, a low photo-anodic charge is consumed (≈ 1 mC.cm−2) and the same ultra-thin film of polyphosphazene onto n-InP is shown by XPS analyses. Properties of this new interface is discussed in term of energy diagram and photo-holes transfer ability. Under these experimental conditions used, (J ≤ 100 µA.cm−2 and Q ≈ 50 mC.cm−2), the passivated interface behaves as a photoanode toward ammonia oxidation since the ultra-thin film is maintained onto InP.

Domaines

Chimie
Fichier non déposé

Dates et versions

hal-04271284 , version 1 (06-11-2023)

Licence

Copyright (Tous droits réservés)

Identifiants

Citer

A. M. Gonçalves, G. Visagli, Cendra P. Rakotoarimanana, C. Njel, Mathieu Frégnaux, et al.. Photoelectrochemical passivation of undoped n-InP by ultra-thin polyphosphazene film: Towards a perfect photoanode?. Electrochimica Acta, 2023, 470, ⟨10.1016/j.electacta.2023.143326⟩. ⟨hal-04271284⟩
17 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More