Tenfold increase in efficiency from a reference blue OLED

• Published in: Journal of luminescence Vol. 199; pp. 13 - 18
• Main Authors: García-Espejo, Gonzalo, Jodlowski, Alexander D., Soriano-Portillo, Alejandra, de Miguel, Gustavo, Muñoz, Eulogia, Pérez-Morales, Marta
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2018
• Subjects: Blue phosphorescent emission; FIrpic; Organic light-emitting diode; Solution-processed devices; Blue phosphorescent emission; Organic light-emitting diode; Solution-processed devices; FIrpic
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2018.03.002

Starting from a reference single-layer light-emitting diode based on the blue phosphorescent bis-cyclometallated iridium complex FIrpic as guest, hosted in a PVK (non-conjugated poly(vynilcarbazole)) matrix, different strategies are followed to improve the efficiency of the devices through the combination of solution processed and evaporated layers. Injection of charges from the electrodes has been varied by using different conductive PEDOT: PSS as hole injection layer and a nanoscale Cs2CO3 interlayer as electron injection and hole-blocking film. Furthermore, a separated electron injection/hole blocking evaporated layer, TPBi or 3TPYMB, is introduced in double-layer devices to enhance the minority carriers (electrons) and also to confine holes to the emissive layer. All these modifications lead to an approximate tenfold improvement in efficiency from the initial reference device. [Display omitted] Starting from a reference OLED based on the blue phosphorescent FIrpic, different strategies to improve its efficiency lead to an approximate tenfold improvement in efficiency from the initial one.