title: Conjugated polymer-titania nanoparticle hybrid films: random lasing action and ultrasensitive detection of explosive vapors.
abstract: We have first demonstrated that a random laser action generated by a hybrid film composed of a semiconducting organic polymer (SOP) and TiO(2) nanoparticles can be used to detect 2,4,6-trinitrotoluene (TNT) vapors. The hybrid film was fabricated by spin-casting SOP solution dispersed with nanosized TiO(2) particles on quartz glass. The SOP in the hybrid film functioned as both the gain medium and the sensory transducer. A random lasing action was observed with a certain pump power when the size (diameter of 50 nm) and concentration (8.9 x 10(12)/cm(3)) of TiO(2) nanoparticles were optimized. Measurements of fluorescence quenching behavior of the hybrid film in TNT vapor atmosphere (10 ppb) showed that attenuated lasing in optically pumped hybrid film displayed a sensitivity to vapors of explosives more than 20 times higher than was observed from spontaneous emission. This phenomenon has been explained with the four-level laser model. Since the sensory transducer used in the hybrid polymer/nanoparticles system could be replaced by other functional materials, the concept developed could be extended to more general domains of chemical or environment detection.
authors.affiliation: Shanghai Institute of Microsystem and Information Technology and Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200050, China.
authors.forename: Changmin
authors.initials: C
authors.lastname: Deng
authors.forename: Qingguo
authors.initials: Q
authors.lastname: He
authors.forename: Chao
authors.initials: C
authors.lastname: He
authors.forename: Liqi
authors.initials: L
authors.lastname: Shi
authors.forename: Jiangong
authors.initials: J
authors.lastname: Cheng
authors.forename: Tong
authors.initials: T
authors.lastname: Lin
mesh_terms: D053834:Explosive Agents / Q000032:analysis / Q000737:chemistry*; D005740:Gases / Q000737:chemistry*; D008163:Luminescent Measurements; D053768:Metal Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011791:Quartz; D014025:Titanium / Q000737:chemistry*; D014303:Trinitrotoluene / Q000032:analysis / Q000737:chemistry*
chemical_list: D053834:Explosive Agents; D005740:Gases; D011108:Polymers; D014303:Trinitrotoluene; D011791:Quartz; C009495:titanium dioxide; D014025:Titanium