Xi Chu

Thin film encapsulated flexible organic electroluminescent displays

We describe encapsulated passive matrix, video rate organic light-emitting diode (OLED) displays on flexible plastic substrates using a multilayer barrier encapsulation technology. The flexible OLED (FOLED™) displays are based on highly efficient electrophosphorescent OLED (PHOLED™) technology deposited on barrier coated plastic (Flexible Glass™ substrate) and are hermetically sealed with an optically transmissive multilayer barrier coating (Barix™ encapsulation). Preliminary lifetime to half initial luminance (L0∼100 cd/m2) of order 200 h is achieved on the passive matrix driven encapsulated 80 dpi displays; 2500 h lifetime is achieved on a dc tested encapsulated 5 mm2 FOLED test pixel. The encapsulated displays are flexed 1000 times around a 1 in. diameter cylinder and show minimal damage.

21.4: Thin Film Encapsulated Flexible OLED Displays

Fully encapsulated passive matrix, video rate, phosphorescent OLED displays on flexible plastic substrates using a multilayer barrier encapsulation technology are described. The flexible OLED (FOLED™) displays are based on highly efficient electrophosphorescent OLED (PHOLED™) technology deposited on barrier coated plastic film (Flexible Glass™ substrate) and are hermetically sealed with an optically transmissive multilayer barrier coating (Barix™ Encapsulation). Preliminary lifetime to half initial luminance (Lo∼100 cd/m2) of order 200 h is achieved on the encapsulated 80 dpi displays using a passive matrix drive at room temperature; 2500 h lifetime is achieved on a dc tested encapsulated 5 mm2 FOLED test pixel. The encapsulated displays are flexed 1000 times around a 1″ diameter cylinder and show minimal damage.

Approaches to Encapsulation of Flexible CIGS Cells

Thin-film solar cells based on CIGS are being considered for large scale power plants as well as building integrated photovoltaic (BIPV) applications. Past studies indicate that CIGS cells degrade rapidly when exposed to moisture. As a result, an effective approach to encapsulation is required for CIGS cells to satisfy the international standard IEC 61646. CIGS modules fabricated for use in large power plants can be encapsulated with glass sheets on the top and bottom surfaces and can be effectively sealed around the edges. In the case of BIPV applications, however, it is desirable to utilize CIGS cells grown on flexible substrates, both for purposes of achieving reduced weight and for cases involving non-flat surfaces. For these cases, approaches to encapsulation must be compatible with the flexible substrate requirement. Even in the case of large power plants, the glass-to-glass approach to encapsulation may eventually be considered too costly. We are investigating encapsulation of flexible CIGS cells by lamination. Sheets of PET or PEN coated with multilayer barrier coatings are used to laminate the flexible cells. Results are discussed for laminated cells from two CIGS manufacturers. In both cases, the cell efficiency decreases less than 10% after 1000 hours of exposure to an environment of 85°C/85%RH. This paper discusses these two approaches, and reviews results for uncoated cells and mini-modules fabricated by the former Shell Solar Industries (SSI).