Combined thermal evaporated and solution processed organic light emitting diodes

• Published in: Organic electronics Vol. 12; no. 10; pp. 1644 - 1648
• Main Authors: Wetzelaer, Gert-Jan A.H., Hartmann, David, Santamaría, Sonsoles García, Pérez-Morales, Marta, Portillo, Alejandra Soriano, Lenes, Martijn, Sarfert, Wiebke, Bolink, Henk J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-10-2011; Elsevier
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Iridium complexes; Light emitting diodes; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optoelectronic devices; Phosphorescent emitters; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solution processing; Vacuum deposition; Iridium complexes; Light emitting diodes; Solution processing; Vacuum deposition; Phosphorescent emitters; Interfacial layer; Performance evaluation; Annealing; Hole transport layer; White light; Iridium complex; Transmitter; Durability; Polymer; Light emitting diode; Light emitting device; Manufacturing process; Spin-on coatings; Optoelectronic device; Organic light emitting diodes; Production cost; Reliability; Growth from solution; Organic electronics
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2011.06.009

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► Partially solution processed red, green and white OLEDs are prepared. ► Performance levels are similar to OLEDs prepared using only vacuum sublimation. ► Stable combined solution processed and evaporated white OLEDs are obtained.
Highly efficient, partly solution processed phosphorescent red, green and white organic light emitting diodes with small molecular weight host materials are prepared from commercially available starting compounds. Starting from an evaporated reference device, layers are stepwise replaced by solution processed layers. Replacing the evaporated hole transport layer by a solution processed polymer interlayer does not affect the performance and allows spincoating of the emissive layer after annealing of the polymer. Devices with, next to the spincoated hole injection and transport layer, a solution processed emission layer show similar characteristics and efficiencies as the reference device. Additionally, white light emitting devices are demonstrated in which the first emissive layer is solution processed, for which lifetimes in excess of 1000
h are achieved. Thus, we show that, in order to reduce production costs, solution processing can be used as an alternative to – and in conjunction with – Thermal evaporation.