Ultrasonic spray coating polymer and small molecular organic film for organic light-emitting devices

Abstract

Ultrasonic spray coating process (USCP) with high material -utilization, low manufacture costs and compatibility to streamline production has been attractive in researches on photoelectric devices. However, surface tension exists in the solvent is still a huge obstacle to realize smooth organic film for organic light emitting devices (OLEDs) by USCP. Here, high quality polymer anode buffer layer and small molecular emitting layer are successfully realized through USCP by introducing extra-low surface tension diluent and surface tension control method. The introduction of low surface tension methyl alcohol is beneficial to the formation of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films and brings obvious phase separation and improved conductivity to PEDOT:PSS film. Besides, a surface tension control method, in which new stable tension equilibrium is built at the border of wetting layer, is proposed to eliminate the effect of surface tension during the solvent evaporation stage of ultrasonic spray coating the film consists of 9,9-Spirobifluoren-2-yl-diphenyl-phosphine oxide doped with 10 wt% tris [2-(p -tolyl) pyridine] iridium (III). A smooth and homogenous small molecular emitting layer without wrinkles is successfully realized. The effectiveness of the ultrasonic spray coating polymer anode buffer layer and small molecular emitting layer are also proved by introducing them in OLEDs.

Stretchable Printed Device for the Simultaneous Sensing of Temperature and Strain Validated in a Mouse Wound Healing Model

“…The superior quality of the PEDOT:PSS layer ensures better transparency and electrical properties of the printed thin lm. USSC has found great importance in high precision thickness (from nanometre scale) and uniform active layer deposition of solar cells, lightemitting diodes, sensors, and other functional coating applications, speci cally in mass volumes [37][38][39]. The prepared samples were then treated with aqueous solutions (1 wt%) of sodium thiosulphate (Na 2 S 2 O 3 ) for 30 seconds and then rinsed with ethanol.…”

3D-printed flexible organic light-emitting diode displays

“…Yet, methodologies to fully print OLED displays require overcoming several challenges to transfer the materials and processes to printing platforms. Previous publications that reported "fully" printed OLEDs relied on spin coating or thermal evaporation to deposit certain components and create functional devices (8)(9)(10)(11)(12). OLED active layers could be printed in place of evaporated or spin-coated counterparts (10,12,13), but the electrodes and interconnects require sputtering or vapor deposition of materials such as metals, metal oxides, and graphene to achieve high electrical conductivity and optical transmittance (14)(15)(16).…”

A comparative approach to enhance the electrical performance of PEDOT:PSS as transparent electrode for organic solar cells

“…9 However, such disadvantages as high-temperature processes, vacuum conditions, decreasing of indium resources, the requirement of acid processes, surface roughness, and brittleness when it is bent 10 -12 have forced the researchers to find alternatives to ITO. Carbon nanotubes, 8,13,14 carbon-based materials like graphenes, 15 -17 conductive polymers, 18,19,3 -6,20 -38 metal grids, 39 -41 nanowires, 42 -44 semitransparent metal layers, 45,46 metal oxides, 47,48 and combination of these materials can be given as examples for alternatives to ITO. These materials are indispensable materials for optoelectronic devices as transparent electrodes.…”

“…49 There are numbers of reports in the literature to enhance the electrical conductivity of PEDOT:PSS by treating the PEDOT:PSS in the solution form or after the film production. 2 -6,20 -38,51,52 PEDOT:PSS polymer consists of PSS as a counter ion, which is nonconductive that enables to be easily dispersed the conductive and cationic PEDOT.…”