Effect of spin-coating process on the performance of passive-matrix organic light-emitting display

Abstract

By improving the spin-coating process during the deposition of hole transport layer poly(3,4-ethylenedioxythiophene)-poly(styrene-sulfonate)(PEDOT:PSS), high efficient monochrome passive-matrix organic light-emitting display is fabricated. The PEDOT:PSS film is spin-coated with a two-step spin-coating process, in which the substrate is turned 180° during the spin-coating, forcing the piled-up materials to move reversely. By introducing the second spin-coating step, the film thickness difference between single and double lines significantly reduces, leading to a more uniform light emission and a larger fill factor for the 3.81 cm monochrome polymer light-emitting diode display. Green light-emitting display with a peak current efficiency of 17 cd/A is successfully fabricated, and the efficiency is improved by 40 percent compared with that made by traditional spin-coating method. A 3.81 cm 96×64 full color display with a current efficiency of 1.25 cd/A is also successfully made.