Electroluminescent materials for white organic light emitting diodes

Abstract

White organic light emitting diodes (WOLEDs) are promising devices for application in low energy consumption lighting since they combine the potentialities of high efficiency and inexpensive production with the appealing features of large surfaces emitting good quality white light. However, lifetime, performances and costs still have to be optimized to make WOLEDs commercially competitive as alternative lighting sources. Development of efficient and stable emitters plays a key role in the progress of WOLED technology. This tutorial review discusses the main approaches to obtain white electroluminescence with organic and organometallic emitters. Representative examples of each method are reported highlighting the most significant achievements together with open issues and challenges to be faced by future research.

Blue Light Emitting Polyphenylene Dendrimers with Bipolar Charge Transport Moieties

“…D1 as a donor-acceptor material without ICT may promise a good blue emitter in OLEDs. The observed dual emission in D2 and PYTPA under polar environments may give an insight into designing new emitters [58]. On a timescale of tens of nanoseconds, the TA spectrum shifts to a feature peaking at 580 nm which further decays with an inverse decay rate of 730 ns.…”

“…D1 as a donor-acceptor material without ICT may promise a good blue emitter in OLEDs. The observed dual emission in D2 and PYTPA under polar environments may give an insight into designing new emitters [58]. [24,59], from reported UPS measurements [23,37,60,61].…”

Люминесенция Полимерной Композиции, Допированной Хелатами Бора. Механизм Сенсибилизации Люминесценции

“…Получение и исследование органических белых люми-нофоров является важным направлением современной науки благодаря развитию техники на основе светоиз-лучающих диодов, где наиболее широко применяются данные вещества [8][9][10]. К числу перспективных веществ для данного приложения относятся β-дикетонаты дифто-рида бора, которые способны излучать белый свет в растворах как одиночных веществ [3], так и в составе композиций люминофоров, где они выступают в каче-стве голубой компоненты [11].…”

Tuning Emission Colors from Blue to Green in Polymeric Light-Emitting Diodes Fabricated using Polyfluorene Blends

“…Different colors can be achieved by preparing different combinations of fluorescent or phosphorescent compounds, 5−21 building multilayer systems in which each layer is composed of molecules or polymers as the active medium, 4,11,13,22 combining multiple layers in a tandem diode architecture, 17 using a single polymer with multiple functional groups, 3,5,18 using mixtures of polymers with small phosphorescent 19 or fluorescent 5,20 molecules (host/guest systems), quantum dots, 22,26 or nanorods/nanotubes, 10,23 using systems with excimer or exciplex emissions, 24,25 using systems that form exciplexes in bilayer structures, 4,6 or preparing blends with conjugated polymers. 7,11,15,16,26−32 The use of polymer blends represents a relatively inexpensive approach to the preparation of novel polymeric electroluminescent (EL) diodes with acceptable performances.…”