A single-layer permeation barrier for organic light-emitting displays

Abstract

Films of a hybrid material with part-SiO2 part-silicone character are deposited as environmental barriers on bottom-emitting and on transparent organic light-emitting diodes. Devices coated with this barrier have lifetimes of up to ∼7500h when stored at 65°C and 85% relative humidity, by far exceeding the industrial requirement of 1000h. The intensity of the Si–O–Si absorption at the wavenumber of 1075cm−1, the wetting angle by water, and the indentation hardness support the interpretation of a homogeneous material with the properties of a SiO2-silicone hybrid. The films remain intact over 58600cycles of bending to ∼0.2% tensile strain.

Organic semiconductors for device applications: current trends and future prospects

“…For instance, the lifetime of encapsulated OLEDs with PECVD SiN x was 600 h compared to 6 h for a bare device [716]. Recently, PECVD SiO x :H films exhibited better protection of OLEDs [708]. Using an appropriate combination of HDMSO and O 2 precursors, it was possible to deposit a single composite layer consisting of SiO 2 and Si, which protected OLEDs up to 7500 h, when stored at 65°C in 85% RH.…”

“…In this method, the adhesive is applied using a syringe, which may cause device damage in case the epoxy touches the semiconductor layers. Alternatively, Al-Li and high-density polyethylene (HDPE) multilayers were used with a half-life of 63 h on glass substrate [709], while elsewhere a combination of oxide, polymer, and epoxy seals [710] was employed for OLEDs on glass with a half-life of over 1000 h. Accelerated testing at 65°C and 85% relative humidity (RH) of PECVD SiO x /Si combinations on glass [708] gave a half-life of 7500 h. For devices prepared on flexible substrates, chemical vapor deposition (CVD) parylene-N/C, individually or in combination, showed four times enhanced lifetime over that of unencapsulated [711] devices. A proprietary barrier formulation on PET gave over 2000 h of half-life [712], whereas a lamination-based encapsulation of OLEDs on plastic substrate showed a half-life of 230 h [713].…”

“…The half-life is estimated by measuring the time after which, for instance, initial brightness of an OLED is reduced to 50%. This is a common method of determining the OLED life that has been used to evaluate the barrier properties [707,708].…”

Neutral-cluster implantation in polymers by computer experiments

“…Polydimethylsiloxane (PDMS) is the most used elastomer substrate because it combines biocompatibility with suitable mechanical properties 13 . Moreover, PDMS can be easily synthesized by available laboratory techniques and it is not attacked by most process chemicals 14 . Amorphous PDMS can be synthesized in different microscopic structures, depending on the applications, including entangled-melt (EM) films (composed by a network of chains strongly wrapped around each other) as well as cross-linked (CL) structures in which individual chains are chemically bonded to each other through suitable cross-linker molecules 15 .…”

Design and fabrication of compositionally graded inorganic oxide thin films: Mechanical, optical and permeation characteristics

“…However, depending on the fabrication process, the extrinsic properties of inorganic oxide thin films are significantly changed by defects such as pinholes or cracks introduced during manufacture. In general, inorganic oxide thin films are fabricated on a substrate by sputtering, chemical vapor deposition (CVD), atomic layer deposition (ALD), laser ablation and sol-gel coating [15][16][17][18][19]. Furthermore, selfsupporting ultrathin films have been developed by several preparative techniques, such as solvent casting, self-assembly ABA triblock copolymer and cross-linking of Langmuir-Blodgett [20][21][22].…”