Luminescent Y₂Zr₂O₇ for Ultrasensitive Detection of Volatile Organic Compounds Driven by Oxygen Vacancies

Abstract

Defect engineering is considered as one of the most efficient strategies to introduce different functionalities in materials suitable to achieve desired properties such as magnetism, catalysis, sensing, and optoelectronic applications. In this study, we have synthesized Y2Zr2O7 (YZO) by the gel combustion method, and subsequent annealing was carried out at different temperatures from 900 to 1300 °C for the engineering of defects. Electron spin resonance spectroscopy suggested the presence of singly ionized oxygen vacancies (F+-center) which resulted in a dual-band bluish-green emission. The color can be tuned from blue to green in moving from the nano to bulk sample in the domain of 900–1300 °C. Photoluminescence quantum yield increases substantially in the bulk samples owing to the lesser density of defect clusters and higher F+ centers. The particle size increases from nano (∼50 nm) to bulk (∼0.4 μm) domain, and surface defects reduce on annealing from 900 to 1300 °C. The pore size is in the mesoporous range, making them suitable for gas sensing purposes. The sensing abilities of nano YZO-900 and bulk YZO-1300 pyrochlore were assessed in terms of detecting volatile organic compounds (VOCs) such as ethanol, acetone, and benzene. The study revealed that the defects in the materials play a significant role in sensing capabilities compared to morphology. On comparisons with other VOC sensors, bulk YZO-1300 not only demonstrated excellent sensitivity and superior response and recovery time toward benzene, but they are equally capable of sensing other polar VOCs such as acetone and ethanol with great ease and lower limit of detection. Moreover, our materials have demonstrated the capability to work as rare-earth-free luminescent materials as well driven by oxygen vacancies.

Oxygen vacancy-enriched Zn2SnO4 for aliphatic alcohol sensing and enhanced selectivity towards n-butanol

“…Compared with the aforementioned simple SMOs, binary/ternary metal oxides (with multiple metal ions) have received widespread attention due to their tuneable electrical conductivities and abundant surface active sites. 15–20 In this regard, zinc stannate (Zn 2 SnO 4 ), a ternary, wide-band-gap n-type SMO is attracting the attention of researchers as a promising gas-sensing material. Zinc stannate-based chemiresistive sensors are already being studied for the detection of various gases, including carbon monoxide (CO), nitrogen dioxide (NO 2 ), methane (CH 4 ), and volatile organic compounds (VOCs).…”

Facile Fabrication and Analysis of Highly Sensitive PtTFPP/Carbon Black/Polystyrene Oxygen-Sensitive Composite Films for Optical Dissolved-Oxygen Sensor

“…They also require the frequent replacement of oxygen-permeable films, which is not cost-effective . This study adopts fluorescence analysis for oxygen measurement, which is based on fluorescence quenching. , It offers high accuracy and the films prepared this way are reusable, long-lasting, and environmentally friendly. , However, they can be expensive. , This study aims to fabricate an oxygen-sensitive film with high performance and low cost, which can be used in dissolved-oxygen sensors. The oxygen-sensitive film is prepared using a suitable substrate and fluorescence indicator dyes, which are often metallic complexes with long fluorescence lifetimes, such as platinum tetrakis­(pentafluorophenyl)­porphyrin (PtTFPP), platinum octaethylporphyrin (PtOEP), and [Ru­(bpy) 3 ]­Cl 2 .…”