Large Polaron Conduction, Photoconductivity, and Photochromism in GdO_xH_3−2x Oxyhydride Thin Films

Large Polaron Conduction, Photoconductivity, and Photochromism in GdO_xH_3−2x Oxyhydride Thin Films

Colombi, G. (TU Delft ChemE/Materials for Energy Conversion and Storage)
Boshuizen, B. (TU Delft ChemE/O&O groep)
Chaykina, D. (TU Delft ChemE/Materials for Energy Conversion and Storage)
Hsu, Y. (TU Delft QN/Kavli Nanolab Delft)
Schreuders, H. (TU Delft ChemE/O&O groep)
Savenije, T.J. (TU Delft ChemE/Opto-electronic Materials)
Dam, B. (TU Delft ChemE/Chemical Engineering)

ChemE/Chemical Engineering

2023

At ambient conditions, rare-earth oxyhydride thin films show reversible photochromism and photoconductivity, while their mechanism and relation are still unclear. In this work, this question is explored with in situ time-resolved measurements of both optical and transport properties of Gd-based oxyhydride thin films. It is found that p-type large polaron conduction is the initial mechanism of charge transport; however, upon photo-darkening, a 10⁴-fold increase of conductivity occurs, and n-type carriers become dominant. Further, photochromism and photoconductivity are shown to originate from a single process, as indicated by the fact that the photoconductivity is exponentially proportional to the increase of optical absorption. This exponential relation, notably, cannot stem from any of the optically absorbing species thought responsible for photochromism and, therefore, suggests that their formation is accompanied by a concerted increase of negative charge carriers in the Gd oxyhydride films.

gadolinium
hydrides
oxyhydrides
photochromism
photoconductivity
polarons

http://resolver.tudelft.nl/uuid:62c34e2b-68f4-40ff-94c0-c0170ec6f1c4

https://doi.org/10.1002/adom.202202660

2195-1071

Advanced Optical Materials, 11 (15)

Institutional Repository

journal article

© 2023 G. Colombi, B. Boshuizen, D. Chaykina, Y. Hsu, H. Schreuders, T.J. Savenije, B. Dam