High-humidity Sensor of a New Trinuclear Ti3-Oxo Cluster

Crystalline polyoxo-titanium clusters (PTCs), as a molecular model of TiO 2 nanomaterials , have attracted unprecedented attention due to their designable structure, tunable band gap, catalysis, and photochromic properties. A new trinuclear Ti 3 -oxo cluster, [Ti 3 (µ 2 -O)(µ 3 -O)(abz) 6 (O i Pr) 2 ] CH 3 CNH 2 O ( Ti3 ), was synthesized by solvothermal method with a yield of 60% by using 4-aminobenzoic acid as ligand. Single-crystal X-ray diffraction shows that it has a [Ti 3 (µ 2 -O)(µ 3 -O)(abz) 6 (O i Pr) 2 ] trinuclear cluster structure. Ti3 crystallizes in monoclinic space group P 2 1 / c with a = 11.091(1), b = 22.837(2), c = 22.754(1) Å, ß = 90.580(6)°, V = 5763.0(6) Å 3 , Z = 4, D c = 1.345 g·cm −3 , F (000) = 2412, µ = 2.743 mm −1 , R = 0.0796, and wR = 0.2260 ( I > 2σ(I)). Ti3 shows typical semiconductive behavior determined by temperature-dependent conductivity test. The chemiresistive humidity sensor fabricated by Ti3 showed good performance, including high response (four orders of magnitude current change from 0 to 100% RH) and fast response time (160 s) and recovery time (26 s).