Molecular semiconductor-doped insulator (MSDI) heterojunctions: Oligothiophene/bisphtalocyanine (LuPc2) and perylene/bisphthalocyanine as new structures for gas sensing

The combination of a sexithiophene and a perylene diimide derivatives, as p-type and n-type materials, respectively, used as sub-layers, to an intrinsic semiconductor, namely the lutetium bisphthalocyanine, allows to obtain a new transducer for gas sensing. These transducers were called molecular semiconductor-doped insulator (MSDI) heterojunctions, were recently designed and reported, but with only phthalocyanines as active materials. p-Type material leads to MSDIs that exhibit a positive response to ozone and a negative response to ammonia, whereas MSDIs prepared from n-type material exhibit a positive response to ammonia and negative response to ozone. The remarkable point is that the only material in contact with the analytes is the lutetium bisphthalocyanine. It means that the inverted responses observed for both p-type and n-type MSDIs come from the modulation of the electronic properties of LuPc2 by the p-type and n-type sub-layers. That study enlarges the potentialities of the MSDIs and opens the way to their promising development in the field of chemical sensors.