Room temperature ammonia sensor based on jaw like bis-porphyrin molecules

• Published in: Organic electronics Vol. 14; no. 4; pp. 1189 - 1196
• Main Authors: Garg, Kavita, Singh, Ajay, Majumder, Chiranjib, Nayak, Sandip K., Aswal, Dinesh K., Gupta, Shiv K., Chattopadhyay, Subrata
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2013; Elsevier
• Subjects: Chemi-resistive sensor; Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Organic semiconductors; Physics; Porphyrin; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Thin films; Thin films; Organic semiconductors; Chemi-resistive sensor; Porphyrin; Amorphous material; Reversible processes; Esters; Selectivity; Recovery time; Zinc; Temperature sensors; Ammonia; Reproducibility; Ambient temperature; Benzene; Spin-on coatings; Reversibility; Resistive transducer; Gas sensors; Gas detector; Porphyrins
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2013.01.033

We have constructed two highly selective ammonia gas (5–40ppm) thin film sensors by spin coating a bis-porphyrin (bis-TPP) and its zinc derivative as the active layers. Both the sensors functioned at room temperature reversibly and showed fast response, the Zn-bis-TPP films being more efficient. [Display omitted] ► Demonstration of two bis-porphyrin-based spin-coated thin-film chemi-resistive room temperature NH3 gas (ppm) sensors. ► Fast and long range of linear response, complete recovery and high selectivity of the sensors. ► Better performance by the Zn–bisporphyrin films due to their rough nature and free entry and exit of NH3 gas. A jaw-like bis-porphyrin (bis-TPP) molecule was synthesized anchoring of two porphyrin molecules to a benzene ring at the meta positions through the ester linkage. The bis-TPP molecule and its zinc-derivative (Zn-bis-TPP) were spin-coated on glass surfaces to construct two chemiresistive room temperature NH3 gas sensors. Both the films showed high selectivity, reproducibility and reversibility in sensing NH3 gas (5–40ppm) in air. The sensing characteristics of the Zn-bis-TPP films (response (2s) and recovery (2.5min) times; linear response (952%)) were better than that of the bis-TPP films (response (8s) and recovery (7.5min) times; linear response (131%)). This is attributed to the amorphous nature of the former.