Emission Area Patterning of Organic Light‐Emitting Diodes (OLEDs) via Printed Dielectrics

Abstract

Solution-processibility is one of the distinguished traits of organic lightemitting diodes (OLEDs) compared to existing solid-state LED technologies. It allows new opportunities which can simplify the fabrication and potentially reduce the cost of manufacturing process. Emission area patterning is one of the crucial fabrication steps and it usually involves subtractive methods, such as photolithography or etching. Here, printing techniques are used to pattern the emission area of blade-coated OLED layers. The print qualities of a number of printing schemes are characterized and compared. Spray coating and screen printing are used to deposit dielectrics with desired patterns on the OLED layers. At luminance of 1000 cd m −2 the OLEDs patterned using spray-coated and screen-printed dielectric show current density of 8.2 and 10.1 mA cm −2 , external quantum efficiency (EQE) of 2.1% and 2.1%, and luminous efficacy of 5.5 and 6.3 lm W −1 , respectively. The OLED characteristics and features of each printing scheme in depositing the dielectric layer are discussed. The printing methods are further applied to demonstrate displays with complex shapes and a seven-segment display.

A flexible organic reflectance oximeter array

“…The OLED arrays are fabricated on top of polyethylene naphthalate (PEN) substrates with patterned indium tin oxide (ITO) for contacts. A surface energy patterning (SEP) step is then performed that creates hydrophilic regions where poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) is blade coated, which is discussed in detail by Han et al ( 15 , 25 ) ( Fig. 2 A , Left ).…”

Liquid Phase Exfoliated Indium Selenide Based Highly Sensitive Photodetectors

“…We investigated the application of β‐InSe based inks in printed photodetectors using a spray coating deposition method. The inks exhibit low viscosity (η 25° ≈ 3.2 mPa × s at 25 °C), with Newtonian behavior at shear rates between 0.2 and 300 s −1 (Figure S1, Supporting Information), which makes them suitable for spray coating deposition 81. An interdigitated gold electrode array was fabricated using EBL and lift‐off (see Section 4) on highly p‐doped (boron) silicon (100) with 100 nm thermal oxide (SiO 2 ) on the surface.…”

High‐Resolution 3D Printing of Freeform, Transparent Displays in Ambient Air

“…Although previous works have been limited to printing only a few components of OLED devices on flat substrates, [55,56] our approach allows the printing of all components of the device and the mechanical frames in ambient air. The 3D architectures of transparent or opaque plastics with arbitrary shapes are printed using DLP, and then all active materials of the OLED displays are printed directly on the 3D surfaces using an e-jet with high resolutions and with no additional thermal annealing steps.…”