A highly efficient humidity sensor based on lead (II) coordination polymer via in-situ decarboxylation and hydrolysis synthesis

Function-oriented design of coordination polymers is emerging as an attracting topic to explore their practical applications, e.g., gas/humidity sensing. However, the successful synthesis of new coordination polymers showing splendid sensing property is an urgent need in fields of materials and sensors, yet still at the initial stage. In this contribution, a new one-dimensional (1D) coordination polymer with formula of [Pb(TAA)(BA)(H₂O)]_n (named as PbL, HTAA = 3-thiopheneacetic acid, HBA = benzoic acid) has been successfully synthesized by a hydrothermal method, which involves in-situ synthesis of both decarboxylation and hydrolysis. As an impedimetric humidity sensing material, this coordination polymer exhibits excellent humidity sensing performance including high response, fast response, small hysteresis, and good repeatability. In the total relative humidity range (11%–97%) at room temperature, it is worth noting that the sensitivity of the humidity sensor is as high as 1.18 × 10⁴, the response time is only 2 s, and the max humidity hysteresis is as small as 1.8%. At last, we discussed the sensing mechanism using the alternating current (AC) impedance technique at various relative humidity.