| abstract |
A display device 110, in particular an organic light emitting device (OLED), includes a light-absorbing layer 140 comprising metal nanoparticles within a matrix material, which helps reduce the reflection of ambient light. The metal nanoparticles may have various regular or irregular shapes with either two or three dimensional structures, and the average particle size lies between 2nm and 20nm, with a maximum particle size distribution +/-75%. The device includes an anode 120, a luminescent region 130 and a cathode 150. The light-absorbing layer may be in any of several positions within the device, including between the cathode and luminescent region, between the anode and luminescent region, within the cathode, within the luminescent region (fig 6), outside of one of the electrodes, or the cathode or the anode may alternatively serve as the light-absorbing layer (see fig 3). The layer may also have a multiple layer configuration (fig 7: 742, 744, 746). Suitable metals for the nanopartilces include those with a characteristic plasma frequency in the visible range, for example Ag, Au, Pt, Pd, Ni, Cu and alloys thereof. The matrix material may be a polymeric, inorganic or organic material, and may be a metal containing compound. |