*** Time dependent evolution of vacancies and metallic domains and their correlation with the photochromic effect in yttrium oxyhydride films revealed by in-situ illumination positron annihilation lifetime spectroscopy *** 
Authors: Ziying Wu, Diana Chaykina, Herman Schreuders, Henk Schut, Martijn de Boer,
Maciej Oskar Liedke, Maik Butterling, Andreas Wagner, Marcel Dickmann, Ekkes Brück, Bernard Dam, and Stephan W. H. Eijt
TU Delft, Faculty of Applied Sciences, Department of Radiation Science and Technology
TU Delft, Faculty of Applied Sciences, Department of Chemical Engineering
Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics
Bundeswehr Universität München, Institut für angewandte Physik und Messtechnik
Corresponding author: Z.Wu 
Contact Information:
Z.Wu-2@tudelft.nl
Delft University of Technology, Faculty of Applied Sciences, Department of Radiation Science and Technology
Buildingnumber 50
Mekelweg 15
2629 JB Delft
The Netherlands
***General Introduction***
This dataset contains data collected during positron annihilation spectroscopy and optical transmittance experiments at Delft University 
of Technology, as part of Ziying Wu's PhD Thesis project (2024): 

It is being made public both to act as supplementary data for publications and the PhD 
thesis of Ziying Wu and in order for other researchers to use this data in their own work.
The data in this data set was collected in the Fundamental Aspects of Materials and Energy group at the Department of Radiation Science and Technology 
and the Materials for Energy Conversion and Storage group at the Department of Chemical Engineering, Delft University of Technology 
between February 2020 and August 2024.
This research project was financially supported by the Guangzhou Elite Project (GEP) and 
the Materials for Sustainability (Mat4Sus) research program, which is financed by the Netherlands Organization for Scientific Research (NWO).
***Purpose of this research and the key experimental methods used***
The purpose of these experiments was to investigate the time-dependent evolution of metallic-like domains and vacancy defects in photochromic yttrium oxyhydride 
thin films. In this study, positron annihilation spectroscopy and transmittance were used, and the corresponding raw and processing data are included in this dataset.
***Description of the data in this data set***
The data in this dataset includes high-resolution figures, and corresponding raw and processing data. The raw and processing data for all 
measurements can be found under the file "raw data" and "processing data". 
The fits of DB-PAS depth profiles were obtained using VEPFIT, the positron lifetime spectra were fitted by PALSfit3.
