Fabrication and Characterization of Large-Pixel Size OLEDs Used for Opto-Biomedical Analysis

With the aim to use a "flat film-like shape" excitation source in the opto-biomedical analysis system (OBMAS), a deep-blue organic light emitting diodes (OLED) with 240 mm2 in size and an emission wavelength of 455 nm were fabricated by vacuum evaporation of low-molecular-weight polymers. In the devices N, N-Bis(naphthalen-1-yl)-. N, N-bis(phenyl) benzidine (NPB) was used for hole transport layer (HTL), 2-methyl-9, 10-bis(naphthalene-2-yl)anthracene (MADN) - for emitting layer (EML) and tris(8-hydroxyquinolinato)aluminum(III) (Alq3) - for electron transport layer (ETL). The output power, the luminous efficiency, the peak wavelength and the full width at half-maximum (FWHM) of the deep-blue OLED were 1.5 mW, 1.0 cd/A, 455 nm and 100 nm, respectively, at a forward current of 30 mA. Under excitation of this excitation source, the photo luminance of the CdSe-QDs attached with listeria monocytogenes bacteria exhibit clear orange colour light. The image of the luminance was detected by a 1.3 Mpx sensitive web cam. This can be used in the biomedical analysis by using an optic microscope acting like an opto-biomedical microanalysis system (OBMAS). With use of the OBMAS one can qualitatively detect the presence of bacteria attached to the QDs through specific antibodies.