It is known that luminescent optical sensors are perspective for detection towards nitroaromatic compounds that are abasis of a many kind of explosives. Operation of these sensors is based on quenching luminescence, which is caused byphoto-induced electron transfer from a luminophore (donor) to a nitroaromatic molecule (acceptor). The conjugatedpolymers, small molecule dyes and metal-organic frameworks are used as a sensitive luminophores currently. One of themethods to improve these sensors is embedding the luminophore into porous matrix with properties of photonic crystal,which may be a porous silicon (pSi) Bragg mirror or a microcavity (MC). The PPV derivatives polymers are usuallyused as the sensitive luminophores for embedding into pSi matrix. However, there is a task to find an optimal set ofluminophores to develop a highly sensitive and selective sensor. In this work we investigate embedding of 5-triphenylamino-4-(triphenylaminothiophen-2-yl)-pyrimidine (HEM-461) into pSi MC and examine the sensitivity ofobtained structures. The pSi MC were fabricated using a standard electrochemical etching process. The eigenmode of thepSi MC had a width of 4-6 nm. The samples were oxidized to stabilize the surface chemical properties and to preventquenching of luminescence of the embedded luminophores after fabrication. The embedding of the dye into the pSi MCwas performed at excess pressure. Well known conjugated polymer MDMO-PPV was used as a reference. In this work,we compared the photophysical properties of MDMO-PPV and HEM-461 in solution and into pSi MC. Theluminescence parameters and resistance to heat have been studied. Comparative studies of sensitivity of MDMO-PPVand HEM-461 to trinitrotoluene in liquid and gaseous phases have been carried out. It was concluded that pSi MC withembedded HEM-461 is a promising structure for developing sensors of nitroaromatic compounds.
展开▼
