Multicolor Heterostructure Organic Leds Based On Selectively Doped Hole-Transport Polymer Layers

In this paper, we report an effective thermal transfer process for performing controllable and selective doping of polymer films for multicolor organic light-emitting devices (OLEDs) or color pixels in OLED displays. In this process, the polymer receiver film is placed in direct contact with the dye-dispersed polymer donor film (with patterns) to permit direct dye-diffusion thermal transfer. It permits controllable lateral and vertical modulations of the dopant distributions of a polymer film for organic devices. Furthermore, it is the intention to combine the selectively doped (patterned) polymer layers with the vacuum deposited small-molecule films, such that both the heterostructure versatility of small-molecule materials and the patterning advantage of polymeric materials could be conserved in the hybrid polymer/small molecule heterstructure OLEDs. The rather thermally stable polymer poly(N-vinylcarbazole) (PVK), which is hole-transport and deep-blue emitting, in combination with several electron-transport molecules has been studied to demonstrate the feasibility of these concepts.