GAS-SENSING PROPERTIES OF PORPHYRIN DIMER LANGMUIR-BLODGETT-FILMS

Langmuir-Blodgett films of a 1:4 mixture of meso,meso'-buta-1,3-diyne- bridged N(II) octaethylporphyrin dimer and arachidic acid have been de posited onto various substrates. The isotherm at the air/water interfa ce and absorbance measurements using polarised light are consistent wi th a planar statistical orientation of the porphyrin dimers which are probably prone onto the arachidic acid tails. The presence in the dime r of the acetylenic linking group allows the formation of a large and highly conjugated molecular structure; this has suggested the use of t he films in gas sensing apparatus. Electrical characterisation in cont rolled atmosphere and with the simultaneous presence of interfering ga seous species, such as C2H5OH, NH3, and CO, suggest that this porphyri n dimer is a promising selective NO gas sensing material. (C) 1998 Els evier Science S.A. All rights reserved.