Morphological and electroluminescent effects of Au nanoparticles on light-emitting polymers

A series of light-emitting alternating copolymers, poly(9,9-dioctylfluorene-alt-thiophene) (PDOFT), end-capped with in situ reduced gold nanoparticles have been synthesized (PDOFT-Au). The 1H-NMR and 13C-NMR spectra corroborate the well-defined structures, and the XPS spectrum serves as direct evidence for the chemical bonding of gold nanoparticles with PDOFTs. All PDOFT-Au(s) are not only soluble in common organic solvents but also have good thermal stability up to 380-410 deg C. The micrographs of TEM show that the size of gold nanoparticles grows up to 20 nm and the particles aggregate into blocks with an increasing quantity of HAuCl4. The colour coordinates of PDOFT-Au10 and PDOFT-Au15, (0.23,0.655) and (0.27,0.649), respectively, are getting close to the standard green (0.2,0.65) demanded by the National Television System Committee (NTSC). In conjunction with their good luminescence properties and photometric efficiencies, PDOFT-Au10 and PDOFT-Au15 are good candidates for green light-emitting materials. PDOFT with a higher content of gold nanoparticles, such as PDOFT-Au30, affords a high current density, and thus is a potential candidate for solar cell or organic thin film transistor (OTFT) devices.