A Porphyrin Pentamer as a Bright Emitter for NIR OLEDs

The luminescence and electroluminescence of an ethyne-linked zinc(II) porphyrin pentamer have been investigated, by testing blends in two different conjugated polymer matrices, at a range of concentrations. The best results were obtained for blends with the conjugated polymer PIDT-2TPD, at a porphyrin loading of 1 wt%. This host matrix was selected because the excellent overlap between its emission spectrum and the absorption spectrum of the porphyrin oligomer leads to efficient energy transfer. Thin films of this blend exhibit intense fluorescence in the near-infrared (NIR), with a peak emission wavelength of 886 nm and a photoluminescent quantum yield (PLQY) of 27% in the solid state. Light-emitting diodes (LEDs) fabricated with this blend as the emissive layer achieve average external quantum efficiencies (EQE) of 2.0% with peak emission at 830 nm and a turn-on voltage of 1.6 V. This performance is remarkable for a singlet NIR-emitter; 93% of the photons are emitted in the NIR (λ > 700 nm), indicating that conjugated porphyrin oligomers are promising emitters for non-toxic NIR OLEDs.

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Ultrabroadband near-infrared luminescence and efficient energy transfer in Bi and Bi/Ho co-doped thin films

Journal of Materials Chemistry C ◽

10.1039/c3tc32177k ◽

2014 ◽

Vol 2 (14) ◽

pp. 2482 ◽

Cited By ~ 25

Author(s):

Beibei Xu ◽

Jianhua Hao ◽

Qiangbing Guo ◽

Juechen Wang ◽

Gongxun Bai ◽

...

Keyword(s):

Thin Films ◽

Energy Transfer ◽

Near Infrared ◽

Efficient Energy Transfer ◽

Efficient Energy ◽

Infrared Luminescence ◽

Co Doped

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White-Light-Emitting Diodes Based on Iridium Complexes via Efficient Energy Transfer from a Conjugated Polymer

Advanced Functional Materials ◽

10.1002/adfm.200500621 ◽

2006 ◽

Vol 16 (5) ◽

pp. 611-617 ◽

Cited By ~ 124

Author(s):

T.-H. Kim ◽

H. K. Lee ◽

O O. Park ◽

B. D. Chin ◽

S.-H. Lee ◽

...

Keyword(s):

Energy Transfer ◽

White Light ◽

Conjugated Polymer ◽

Light Emitting Diodes ◽

Iridium Complexes ◽

Efficient Energy Transfer ◽

Light Emitting ◽

Efficient Energy ◽

White Light Emitting Diodes

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Two-dimensional perovskites with alternating cations in the interlayer space for stable light-emitting diodes

Nanophotonics ◽

10.1515/nanoph-2021-0037 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Yiyue Zhang ◽

Masoumeh Keshavarz ◽

Elke Debroye ◽

Eduard Fron ◽

Miriam Candelaria Rodríguez González ◽

...

Keyword(s):

Thin Films ◽

Near Infrared ◽

Light Emitting Diodes ◽

Interlayer Space ◽

High Current Density ◽

Operational Stability ◽

Infrared Light ◽

Two Dimensional ◽

Commercial Development ◽

Light Emitting

Abstract Lead halide perovskites have attracted tremendous attention in photovoltaics due to their impressive optoelectronic properties. However, the poor stability of perovskite-based devices remains a bottleneck for further commercial development. Two-dimensional perovskites have great potential in optoelectronic devices, as they are much more stable than their three-dimensional counterparts and rapidly catching up in performance. Herein, we demonstrate high-quality two-dimensional novel perovskite thin films with alternating cations in the interlayer space. This innovative perovskite provides highly stable semiconductor thin films for efficient near-infrared light-emitting diodes (LEDs). Highly efficient LEDs with tunable emission wavelengths from 680 to 770 nm along with excellent operational stability are demonstrated by varying the thickness of the interlayer spacer cation. Furthermore, the best-performing device exhibits an external quantum efficiency of 3.4% at a high current density (J) of 249 mA/cm2 and remains above 2.5% for a J up to 720 mA cm−2, leading to a high radiance of 77.5 W/Sr m2 when driven at 6 V. The same device also shows impressive operational stability, retaining almost 80% of its initial performance after operating at 20 mA/cm2 for 350 min. This work provides fundamental evidence that this novel alternating interlayer cation 2D perovskite can be a promising and stable photonic emitter.

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Sensitizing effect of Yb3+ on near-infrared fluorescence emission of Cr4+-doped calcium aluminate glasses

Journal of Materials Research ◽

10.1557/jmr.2000.0045 ◽

2000 ◽

Vol 15 (2) ◽

pp. 278-281 ◽

Cited By ~ 4

Author(s):

Yong Gyu Choi ◽

Kyong Hon Kim ◽

Yong Seop Han ◽

Jong Heo

Keyword(s):

Energy Transfer ◽

Calcium Aluminate ◽

Near Infrared ◽

Fluorescence Emission ◽

Dipole Interaction ◽

Energy Transfer Mechanism ◽

Efficient Energy Transfer ◽

Efficient Energy ◽

Sensitizing Effect ◽

Decay Behavior

We have demonstrated that an efficient energy transfer takes place from Yb3+ to Cr4+ in calcium aluminate glasses. Yb3+ improves excitation efficiency at around 980 nm, enhancing emission intensity of Cr4+ fluorescence at 1.2–1.6 μm. Nonradiative energy transfer via electric dipole–dipole interaction between ytterbium and chromium ions was found to be dominant over radiative Yb3+ → Cr4+ energy transfer. A diffusionlimited energy transfer mechanism well explains the decay behavior of Yb3+/Cr4+- codoped glasses. This codoping scheme may be applicable to other Cr4+-containing crystals and glasses.

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A CORRESPONDING RELATION BETWEEN ELECTROLUMINESCENT INTENSITY AND THE ENERGY AND CHARGE TRANSFER IN DOPED ORGANIC ELECTROLUMINESCENT DEVICES

Modern Physics Letters B ◽

10.1142/s021798490801745x ◽

2008 ◽

Vol 22 (30) ◽

pp. 2979-2986

Author(s):

HONG-JIAN LI ◽

ZHI-JUN WANG ◽

JUN-XI WANG ◽

XUE-YONG LI ◽

HUI XIA ◽

...

Keyword(s):

Charge Transfer ◽

Conjugated Polymer ◽

Fluorescence Spectra ◽

Dopant Concentration ◽

Quantitative Relation ◽

Efficient Energy Transfer ◽

Electroluminescent Devices ◽

Efficient Energy ◽

Hamiltonian Model ◽

Organic Electroluminescent

In doped organic electroluminescent devices (OLEDs), the changes of the fluorescence spectra occurred due to the energy and charge transfer from guest to host. A quantitative relation between the energy and charge transfer for doping OLEDs was studied by means of a Hamiltonian model. It was found that there is a corresponding relation between the EL intensity of doped PVK and the amount of the transferred charge and the change of the energy derived from charge transfer with dopant concentration, and the more the amount of the transferred charge and the decreasing of the energy from charge transfer, the higher the EL intensity in doped OLEDs. We can deduce that the efficient energy transfer results from the transferred charge between PVK and perylene. Based on the transport mechanism of carriers in conjugated polymer, an expression of conductivity was presented. Calculated results indicated that there is also a corresponding relation between the EL intensity of doped PVK and conductivities with dopant concentration. The larger the conductivities, the higher the EL intensity in doped OLEDs.

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Photo and Electroluminescent Properties of a Porphyrin-Poly(p-Phenylene Vinylene) Derivative

MRS Proceedings ◽

10.1557/proc-598-bb3.57 ◽

1999 ◽

Vol 598 ◽

Author(s):

J. Morgado ◽

R. Iqbal ◽

G. Yahioglu ◽

L. R. Milgrom ◽

S. C. Moratti ◽

...

Keyword(s):

Energy Transfer ◽

Solid State ◽

Emission Spectra ◽

Luminescent Properties ◽

Phenylene Vinylene ◽

Efficient Energy Transfer ◽

Light Emitting ◽

Efficient Energy ◽

Small Absorption ◽

Pl Emission

ABSTRACTThe solid state luminescent properties of new statistical copolymers of 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene and a porphyrin-substituted phenylene vinylene are reported. The photoluminescence, PL, emission shows an efficient energy transfer to the porphyrin, in spite of the small absorption coefficient of the porphyrin in the wavelength range of the poly [2-methoxy-5-(2'- ethylhexyloxy)-1,4-phenylene vinylene], MEH-PPV, emission. At a porphyrin content of 0.25%, by weight, the emission is already dominated by the porphyrin. The PL efficiency of these copolymers is significantly reduced from the value of 13% for MEH-PPV down to 3% for the copolymer with 10.84% of porphyrin. Efficient energy transfer is also observed in the emission spectra of light-emitting diodes.

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