Novel transport materials for high-performance fluorescent and phosphorescent OLEDs

Böhm, Edgar; Anemian, Rémi; Büsing, Arne; Fortte, Rocco; Heil, Holger; Kaiser, Joachim; Kröber, Jonas; Leu, S.; Mujica-Fernaud, T.; Parham, Amir; Pflumm, Christof; Voges, Frank

doi:10.1080/15980316.2011.593909

Cited by 10 publications

(15 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the use in evaporation, Electron Transport Materials (ETMs) have been introduced along with new blue host/guest systems (SMBs/SEBs) [1]. Also, new Triplet Matrix Materials (TMMs) allowing for long operative lifetime operation have been developed [2].…”

Section: Conceptmentioning

confidence: 99%

5.1: Purity of OLED‐Materials and the Implication on DevicePerformance

Becker

Bach

Holbach

et al. 2010

Symp Digest of Tech Papers

View full text Add to dashboard Cite

show abstract

Section: Conceptmentioning

confidence: 99%

5.1: Purity of OLED‐Materials and the Implication on DevicePerformance

Becker

Bach

Holbach

et al. 2010

Symp Digest of Tech Papers

View full text Add to dashboard Cite

show abstract

“…Nonetheless, considering steep relationships between voltage and current density typically observed in OLEDs, as well as a limited range of maximum luminances required for practical applications, operating voltages within a few volts of a thermodynamic limit are often considered to be 'close' to the theoretical limit. Furthermore, although minor reductions in operating voltages can be frequently achieved through specific device structure optimization involving, for example, transport and injection material selection, such improvements may be associated with some undesirable side effects, such as a decline in device durability [2][3][4]. Fine details aside, there is clearly a striking improvement in operating voltages of OLEDs when compared, for example, with approximately 6.5 V and approximately 14 V values at 20 mA cm −2 for the first examples of, respectively, small molecule-based [1] and polymer-based [5] devices, both emitting green-yellow light with an average photon energy slightly above 2 eV.…”

Section: Introductionmentioning

confidence: 99%

Triplet–triplet annihilation in highly efficient fluorescent organic light-emitting diodes: current state and future outlook

Kondakov

2015

Phil. Trans. R. Soc. A.

137

119

View full text Add to dashboard Cite

Studies of delayed electroluminescence in highly efficient fluorescent organic light-emitting diodes (OLEDs) of many dissimilar architectures indicate that the triplet–triplet annihilation (TTA) significantly increases yield of excited singlet states—emitting molecules in this type of device thereby contributes substantially to their efficiency. Towards the end of the 2000s, the essential role of TTA in realizing highly efficient fluorescent devices was widely recognized. Analysis of a diverse set of fluorescent OLEDs shows that high efficiencies are often cor-related to TTA extents. It is therefore likely that it is the long-term empirical optimization of OLED efficiencies that has resulted in fortuitous emergence of TTA as a large and ubiquitous contributor to efficiency. TTA contributions as high as 20–30% are common in the state-of-the-art OLEDs, and even become dominant in special cases, where TTA is shown to substantially exceed the spin-statistical limit. The fundamental features of OLED efficiency enhancement via TTA—molecular structure-dependent contributions, current density-dependent intensities in practical devices and frequently observed antagonistic relationships between TTA extent and OLED lifetime—came to be understood over the course of the next few years. More recently, however, there was much less reported progress with respect to all-important quantitative details of the TTA mechanism. It should be emphasized that, to this day and despite the decades of work on improving blue phosphorescent OLEDs as well as the recent advent of thermally activated delayed fluorescence OLEDs, the majority of practical blue OLEDs still rely on TTA. Considering such practical importance of fluorescent blue OLEDs, the design of blue OLED-compatible materials capable of substantially exceeding the spin-statistical limit in TTA, elimination of the antagonistic relationship between TTA-related efficiency gains and lifetime losses, and designing devices with an extended range of current densities producing near-maximum TTA electroluminescence are the areas where future improvements would be most beneficial.

show abstract

“…optimize because deterioration of these layers affects the EML directly, and would be led to short lifetime. Moreover, we improved the lifetime with using a high stable hole-transport layer (HTL) material since it is known that the lifetime increases with a hole-dominant OLED compared with an electrondominant one [4,5]. In this paper, we will demonstrate the improvement for the lifetime of the blue OLED, particularly at high temperature, and its analysis.…”

Section: Introductionmentioning

confidence: 94%

“…Böhm et al reported that the lifetime becomes long with the hole-dominant OLED compared with the electron-dominant one [4,5]. This means that the characteristic of the HTL material is important for the lifetime of OLEDs.…”

Section: Improvement Of the Lifetime By The Htl Materialsmentioning

confidence: 99%