Hierarchical Self‐Assembly of Tetrakis(1‐pyrenyl)porphyrins into Microscopic Petals and Flowers with Ultrasensitive Room‐Temperature NO₂ Sensing in a Broad Humidity Range

Abstract

A metal free meso‐tetrakis(1‐pyrenyl)porphyrin H2T[(Pyr)4]P (1) and its cobalt congener CoT[(Pyr)4]P (2) are firstly fabricated into the hierarchical nanopetals and micro‐ball‐flowers, respectively, by a simple solution‐based method. Unexpectedly highly sensitive, stable, selective and reproducible responses to 50–400 ppb NO2 gas are obtained at room temperature for the aggregates of both 1 and 2, within 2 min dynamic exposure period at a broad relative humidity (RH) range of 0%‐75%. In particular, the micro‐ball‐flowers of 2 achieve a sensitivity of 91.4 and 214% ppm−1 at 45% RH and 75% RH, respectively, demonstrating the potentials as chemical sensors operating in real‐world atmospheres. Furthermore, the sensitivity of 1 and 2 remains almost unchanged under 0%–75% RH after 6 months. The present work represents one of the best results among organic‐based ppb‐level NO2 sensors operating under a broad RH range in terms of sensitivity and stability to humidity variations at room temperature.

Solution-processed filamentous copper phthalocyanine films for enhanced NO2 gas sensing at room temperature

“…Sun 13 prepared nano-petal and spherulofloral OSCs of tetrapyrene porphyrins using the solution method. The OFET sensors could detect NO 2 gas at 50–400 ppb with high sensitivity, selectivity, and repeatability.…”

Metalloporphyrin-Based Metal–Organic Frameworks for the Ultrasensitive Chemiresistive Detection of NO2: Effect of the Central Metal on Tuning the Sensing Performance

“…This is also the main reason that the performance in terms of sensitivity and limit of detection (LOD) of most organic semiconductor NO 2 sensors is far behind those of traditional metal oxide gas sensors. Therefore, a combination of unique properties offered by organic and inorganic sensing components in a single heterogeneous material with more exposed sensing active sites, high conductivity, and a clear structure has become one of the research focuses and still remains a challenge in this field. − …”