Polylactide-perylene derivative for blue biodegradable organic light-emitting diodes

Abstract

In this work we demonstrate, for the first time, the use of polylactic acid (PLA) as a biodegradable host matrix for the construction of the active emissive layer of organic light-emitting diode (OLED) devices for potential use in bioelectronics. In this preliminary study, we report a robust synthesis of two fluorescent PLA derivatives, pyrene-PLA (AH10) and perylene-PLA (AH11). These materials were prepared by the ring opening polymerisation of l-lactide with hydroxyalkyl-pyrene and hydroxyalkyl-perylene derivatives using 1,8-diazabicyclo[5.4.0]undec-7-ene as catalyst. OLEDs were fabricated from these materials using a simple device architecture involving a solution-processed single-emitting layer in the configuration ITO/PEDOT:PSS/PVK:OXD-7 (35%):AH10 or AH11 (20%)/TPBi/LiF/Al (ITO, indium tin oxide; PEDOT:PSS, poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonic acid); PVK, poly(vinylcarbazole); OXD-7, (1,3-phenylene)-bis-[5-(4-tert-butylphenyl)-1,3,4-oxadiazole]; TPBi, 2,2′,2″-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole)). The turn-on voltage for the perylene OLED at 10 cd m–2 was around 6 V with a maximum brightness of 1200 cd m–2 at 13 V. The corresponding external quantum efficiency and device current efficiency were 1.5% and 2.8 cd A–1 respectively. In summary, this study provides proof of principle that OLEDs can be constructed from PLA, a readily available and renewable bio-source. © 2020 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.