Formation of vacancies and metallic-like domains in photochromic rare-earth oxyhydride thin films studied by in-situ illumination positron annihilation spectroscopy

Rare-earth (RE) oxyhydride thin films show a color-neutral, reversible photochromic effect at ambient conditions. The origin of the photochromism is the topic of current investigations. Here, we investigated the lattice defects, electronic structure, and crystal structure of photochromic YHxOy and GdHxOy thin films deposited by magnetron...

Characterization of Enzymatically Synthesized Titania Thin Films Using Positron Annihilation Spectroscopy Reveals Low-Cost Approach for Organic/Inorganic Photovoltaic Cells

A new method is developed to produce mesoporous titania thin films at room temperature using the enzyme papain in a dip-coating procedure, providing low-cost titania films in a sustainable manner. Quartz crystal microbalance, positron annihilation Doppler broadening and lifetime spectroscopy, scanning electron microscopy, and X-ray...

Photochromic YO_xH_y thin films examined by in situ positron annihilation spectroscopy

Doppler broadening positron annihilation spectroscopy depth profiles were collected on photochromic YO_xH_y thin films. In situ UV illumination of photochromic semiconductor YO_xH_y films leads to an increase in S-parameter and a large reduction in W-parameter, possibly caused by a change in the charge...

Nature of the Positron State in CdSe Quantum Dots

Previous studies have shown that positron-annihilation spectroscopy is a highly sensitive probe of the electronic structure and surface composition of ligand-capped semiconductor quantum dots (QDs) embedded in thin films. The nature of the associated positron state, however, whether the positron is confined inside the QDs or localized at...

New insights into the nanostructure of innovative thin film solar cells gained by positron annihilation spectroscopy

Recent studies showed that positron annihilation methods can provide key insights into the nanostructure and electronic structure of thin film solar cells. In this study, positron annihilation lifetime spectroscopy (PALS) is applied to investigate CdSe quantum dot (QD) light absorbing layers, providing evidence of positron trapping at the...