Journal ArticleDOI
White organic light-emitting diodes with fluorescent tube efficiency
Sebastian Reineke,Frank Lindner,Gregor Schwartz,Nico Seidler,Karsten Walzer,Björn Lüssem,Karl Leo +6 more
TLDR
An improved OLED structure which reaches fluorescent tube efficiency and focuses on reducing energetic and ohmic losses that occur during electron–photon conversion, which could make white-light OLEDs, with their soft area light and high colour-rendering qualities, the light sources of choice for the future.Abstract:
The development of white organic light-emitting diodes (OLEDs) holds great promise for the production of highly efficient large-area light sources. High internal quantum efficiencies for the conversion of electrical energy to light have been realized. Nevertheless, the overall device power efficiencies are still considerably below the 60-70 lumens per watt of fluorescent tubes, which is the current benchmark for novel light sources. Although some reports about highly power-efficient white OLEDs exist, details about structure and the measurement conditions of these structures have not been fully disclosed: the highest power efficiency reported in the scientific literature is 44 lm W(-1) (ref. 7). Here we report an improved OLED structure which reaches fluorescent tube efficiency. By combining a carefully chosen emitter layer with high-refractive-index substrates, and using a periodic outcoupling structure, we achieve a device power efficiency of 90 lm W(-1) at 1,000 candelas per square metre. This efficiency has the potential to be raised to 124 lm W(-1) if the light outcoupling can be further improved. Besides approaching internal quantum efficiency values of one, we have also focused on reducing energetic and ohmic losses that occur during electron-photon conversion. We anticipate that our results will be a starting point for further research, leading to white OLEDs having efficiencies beyond 100 lm W(-1). This could make white-light OLEDs, with their soft area light and high colour-rendering qualities, the light sources of choice for the future.read more
Citations
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Journal ArticleDOI
Efficient planar heterojunction perovskite solar cells by vapour deposition
TL;DR: It is shown that perovskite absorbers can function at the highest efficiencies in simplified device architectures, without the need for complex nanostructures.
Journal ArticleDOI
Deep ultraviolet photoluminescence of water-soluble self-passivated graphene quantum dots
Libin Tang,Rongbin Ji,Xiangke Cao,Jingyu Lin,Hongxing Jiang,Li Xueming,Kar Seng Teng,Chi Man Luk,Songjun Zeng,Jianhua Hao,Shu Ping Lau +10 more
TL;DR: The G QDs are capable of converting blue light into white light when the GQDs are coated onto a blue light emitting diode and the photoluminescence quantum yields were determined to be 7-11%.
Journal ArticleDOI
Light-emitting diodes by band-structure engineering in van der Waals heterostructures
Freddie Withers,O. Del Pozo-Zamudio,Artem Mishchenko,A. P. Rooney,Ali Gholinia,Kenji Watanabe,T. Taniguchi,Sarah J. Haigh,Andre K. Geim,Alexander I. Tartakovskii,Kostya S. Novoselov +10 more
TL;DR: In this paper, the authors describe light-emitting diodes (LEDs) made by stacking metallic graphene, insulating hexagonal boron nitride and various semiconducting monolayers into complex but carefully designed sequences.
Journal ArticleDOI
Recent Progresses on Materials for Electrophosphorescent Organic Light-Emitting Devices
TL;DR: Blue phosphorescence approaching the theoretical efficiency has also been achieved, which may overcome the final obstacle against the commercialization of full color display and white light sources from phosphorescent materials.
References
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Journal ArticleDOI
Highly efficient phosphorescent emission from organic electroluminescent devices
Marc A. Baldo,D. F. O’Brien,Yujian You,Andrei Shoustikov,Scott Sibley,Scott Sibley,Mark E. Thompson,Stephen R. Forrest +7 more
TL;DR: In this article, a host material doped with the phosphorescent dye PtOEP (PtOEP II) was used to achieve high energy transfer from both singlet and triplet states.
Journal ArticleDOI
Management of singlet and triplet excitons for efficient white organic light-emitting devices
Yiru Sun,Noel C. Giebink,Hiroshi Kanno,Biwu Ma,Mark E. Thompson,Stephen R. Forrest,Stephen R. Forrest +6 more
TL;DR: This device challenges incandescent sources by exhibiting total external quantum and power efficiencies that peak at 18.7 ± 0.6 lm W-1, respectively, and two distinct modes of energy transfer within this device serve to channel nearly all of the triplet energy to the phosphorescent dopants, retaining the singlet energy exclusively on the blue fluorescent dopant.
Journal ArticleDOI
Multilayer White Light-Emitting Organic Electroluminescent Device
TL;DR: The fabrication of a white light-emitting organic electroluminescent device made from vacuum-deposited organic thin films is reported, which was successfully obtained at low drive voltages such as 15 to 16 volts.
Journal ArticleDOI
Transient analysis of organic electrophosphorescence. II. Transient analysis of triplet-triplet annihilation
TL;DR: Baldo et al. as mentioned in this paper showed that the observed decrease in electrophosphorescent intensity in organic light-emitting devices at high current densities is principally due to triplet-triplet annihilation.