{'fraction_non_alphanumeric': 0.03992901508429459, 'fraction_numerical': 0.032830523513753325, 'mean_word_length': 4.696969696969697, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
FexNi(1-x)O/NiO Heterojunction-Based Selective VOC Sensor Device by Using Temperature Tunability

Monitoring air quality is quintessential for maintaining sound human health. In our work, a p-p heterojunction device based on FexNi(1-x)O/NiO was fabricated via mild solvent based approach. The device was subjected to calculated concentrations of VOC vapors (viz. 2-propanol, toluene and formaldehyde) at varying operating temperatures between 150 °C and 350 °C. It was seen that the sensor could be made selective towards the different VOCs (e.g. 2-propanol at 200 °C, toluene at 250 °C and formaldehyde at 300 °C) by tuning the operating temperature. The sensor response was maximum for formaldehyde (2.1 with 76 ppm) and was found to be reasonably fast (response time 58 sec and recovery time 46 sec). The theoretical LOD was obtained as 0.77 ppm for 2-propanol, 0.83 ppm for toluene and 0.78 ppm for formaldehyde. Thus, it was possible for selectively sense different VOCs by a single sensor device by varying its operating temperature which may introduce a smart sensing solution with high market feasibility in the future.