Large-Area Printed Display Based on Green Solvent Processable Blue Light-Emitting Conjugated Polymer

Green-processable printed large-area light-emitting diode (LED) is the crucial component of the high quality solid lighting and flat-panel display. Accelerating the replacement from fossil-based solvents to sustainable ecofriendly solvent is desirable for solution-based printed organic electronics. Herein, by simple introducing methyl to the benzene groups of polydiarylfluorene-based polymer, this work realizes the solution processing of blue polymer light-emitting diodes (PLEDs) with a bio-based solvent of limonene toward large-area printed display. Film processed from this solvent exhibits satisfactory morphology and remarkable photophysical performances, even though the polymer chains show more serious aggregation in solution. What's more, devices fabricated with spin-coated films present higher external quantum efficiency (EQE) and better spectra repeatability. Encouraged by the good film-forming ability of this polymer in limonene, this work realizes the fabrication of printed large-area films (5 x 5 cm(2)) with uniform emission and surface morphology by blade coating. Furthermore, this work develops passive matrix (PM) PLEDs arrays with 20 x 20 pixels that can dynamically display monochrome letters and numbers, demonstrating the potential application of cost-effective printing techniques in large-area display.