title: Integrated thin-film polymer/fullerene photodetectors for on-chip microfluidic chemiluminescence detection.
abstract: We report the use of solution-processed thin-film organic photodiodes for microscale chemiluminescence. The active layer of the photodiodes comprised a 1 : 1 blend by weight of the conjugated polymer poly(3-hexylthiophene) [P3HT] and [6,6]-phenyl-C(61)-butyric acid-methylester [PCBM]--a soluble derivative of C(60). The devices had an active area of 1 mm x 1 mm, and a broad-band response from 350 to 700 nm, with an external quantum efficiency of more than 50% between 450 and 550 nm. The photodiodes have a simple layered structure that permits facile integration with planar chip-based systems. To evaluate the suitability of the organic devices as integrated detectors for microscale chemiluminescence, a peroxyoxalate based chemiluminescence reaction (PO-CL) was monitored within a poly(dimethyl-siloxane) (PDMS) microfluidic device. Quantitation of hydrogen peroxide indicated excellent linearity and yielded a detection limit of 10 microM, comparable with previously reported results using micromachined silicon microfluidic chips with integrated silicon photodiodes. The combination of organic photodiodes with PDMS microfluidic chips offers a means of creating compact, sensitive and potentially low-cost microscale CL devices with wide-ranging applications in chemical and biological analysis and clinical diagnostics.
authors.affiliation: Experimental Solid State Physics Group, Blackett Laboratory, Imperial College London, UK.
authors.forename: Xuhua
authors.initials: X
authors.lastname: Wang
authors.forename: Oliver
authors.initials: O
authors.lastname: Hofmann
authors.forename: Rupa
authors.initials: R
authors.lastname: Das
authors.forename: Edward M
authors.initials: EM
authors.lastname: Barrett
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: deMello
authors.forename: John C
authors.initials: JC
authors.lastname: deMello
authors.forename: Donal D C
authors.initials: DD
authors.lastname: Bradley
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004867:Equipment Design; D037741:Fullerenes / Q000737:chemistry*; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods; D010777:Photochemistry; D012680:Sensitivity and Specificity; D012828:Silicones / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D004129:Dimethylpolysiloxanes; D037741:Fullerenes; D012828:Silicones; D013876:Thiophenes; C507295:poly(3-hexylthiophene); C013830:baysilon