Chloroform sensing properties of Langmuir-Blodgett thin films of Zn(II)phthalocyanine containing 26-membered tetraoxadithia macrocycle groups

Abstract

A zinc(II)phthalocyanine containing 26-membered tetraoxadithia macrocycle moiety (ZnPc-26) was prepared for the fabrication of multilayered Langmuir-Blodgett (LB) thin films. The LB thin film fabrication procedure is given in detail with the isotherm and the transfer graph where the transfer ratio was calculated as 0.95. LB thin film quality is monitored by the UV-Vis and SPR with respect to the increasing number of layers with linear regressions of 0.998 and 0.979 respectively. 8, 12 and 20 layered ZnPc-26 LB thin films are selected to investigate the chloroform sensing properties. The response times between 2 and 6 s are observed with reproducible and reversible responses. Limit of detection value of 3.76 ppm was calculated with a sensitivity of 0.797 × 10−3 ppm−1 for the 20 layered ZnPc-26 LB thin film. A reduction of approximately 20% in the response rate was observed after 5 weeks from the first investigation. ZnPc-26 molecule has a potential for the gas sensing applications.