Summary:
Sealing of OLEDs using ion-assisted deposited passivation layer (SiON) as opposed to glue has been found to greatly increase the longevity of the displays. SiON has a lower water permeability than conventional glues, the main cause of reduced life-times of OLEDs. Note: these OLEDs are compared against unencapsulated OLEDs, not commercial benchmarks, and the results are far less impressive when this is borne in mind. Overhyped IMAO. (published: 23/04/2008)
Notes:
- OLEDs promising for next generation of displays and solid state lighting
- use less power
- can be more efficiently manufactured
- better color
- capability of larger displays
- lacking is an inexpensive encapsulation method to mass produce organic electronics that doesn't let moisture in
- currently displays sealed in inert atmosphere or in vacuum
- glass lid glued on top of display substrate
- moisture absorbing powder inside
- expensive and labor-intensive to assemble
- Georgia Tech Research Institute (GTRI)
- Wusheng Tong, senior research scientist
- Hisham Menkara, senior research scientist
- Brent Wagner, principle research scientist
- thin film barrier, pinhole free SiON (silicon oxynitride)
- ion assisted deposition
- relatively inexpensive
- performed at room temperature, thus keep organics material intact
- 50-200nm
- thinner increases risk of pinholes
- no sign of degradation after 7 months using SiON barrier
- as opposed to 2 weeks unencapsulated, same conditions
- note: this is to be expected without encapsulation
- accelerated degradation tests at 50°C and 50% relative humidity
- little degradation after 2 weeks
- note: 2 weeks at 50°C and 50% RH not very impressive
- unencapsulated OLEDs degraded immediately
- note: again, this is to be expected without encapsulation
- Note: these devices should be compared against an industry standard (e.g. a Kodak OLED) rather unencapsulated displays
