High‐Efficiency Solution‐Processed Small Molecule Electrophosphorescent Organic Light‐Emitting Diodes

Cai, Min; Xiao, Teng; Hellerich, Emily; Chen, Ying; Shinar, Ruth; Shinar, J.

doi:10.1002/adma.201101154

Cited by 190 publications

(142 citation statements)

References 58 publications

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“…After that, because of well-known intrinsic charging effects of this type of polymer 32,33 , the charge carrier recombination zone drifts away from the dopant molecule under investigation. Either by discharging or applying a reverse bias in the opposite direction the recombination zone can be shifted backwards again.…”

Section: Discussionmentioning

confidence: 99%

Electrically driven photon antibunching from a single molecule at room temperature

et al. 2012

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single-photon emitters have been considered for applications in quantum information processing, quantum cryptography and metrology. For the sake of integration and to provide an electron photon interface, it is of great interest to stimulate single-photon emission by electrical excitation as demonstrated for quantum dots. Because of low exciton binding energies, it has so far not been possible to detect sub-Poissonian photon statistics of electrically driven quantum dots at room temperature. However, organic molecules possess exciton binding energies on the order of 1 eV, thereby facilitating the development of an electrically driven single-photon source at room temperature in a solid-state matrix. Here we demonstrate electroluminescence of single, electrically driven molecules at room temperature. By careful choice of the molecular emitter, as well as fabrication of a specially designed organic lightemitting diode structure, we were able to achieve stable single-molecule emission and detect sub-Poissonian photon statistics.

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Section: Discussionmentioning

confidence: 99%

Electrically driven photon antibunching from a single molecule at room temperature

et al. 2012

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“…A printing process can be applied for various low-cost organic electronic device applications such as organic thin film transistors (OTFTs) [1], organic solar cells (OSCs) [2], radio frequency identification (RFID) [3], organic sensors [4], and organic light emitting diodes (OLEDs) [5]. Printing technology such as inkjet and nozzle printing process-based OLEDs have received huge interest from many companies and research groups.…”

Section: Introductionmentioning

confidence: 99%

Nozzle Printed-PEDOT:PSS for Organic Light Emitting Diodes with Various Dilution Rates of Ethanol

et al. 2018

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Abstract:In this study, we investigated the ink formulation of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the hole injection layer (HIL) in an organic light emitting diode (OLED) structure. Generally, in a PEDOT:PSS solution, water is incorporated in the solution for the solution process. However, the fabrication of thin film which contained the water, main solvent, could not easily form by using printing technology except spin-coating process because of the high surface tension of water. On the other hand, mixing PEDOT:PSS solution and ethanol (EtOH), a dilution solvent, could restrain the non-uniform layer that forms by the high surface tension and low volatility of water. Therefore, we printed a PEDOT:PSS solution with various concentrations of EtOH by using a nozzle printer and obtained a uniform pattern. The line width of PEDOT:PSS diluted with 90% (volume ratio) ehtanol was measured as about 4 mm with good uniformity with a 0.1 mm nozzle. Also, imaging software and a scanning electron microscope (SEM) were used to measure the uniformity of PEDOT:PSS coated on a substrate. Finally, we fabricated a green phosphorescent OLED device with printed-PEDOT:PSS with specific concentrations of EtOH and we achieved a current efficiency of 27 cd/A with uniform quality of luminance in the case of device containing 90% EtOH.

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“…AFM scans of the EML on [ITO or Ag 40 nm]/MoO x [5 or 20 nm] show that the PVK:CBP layer is smooth (R RMS 6 1 nm), slightly more so with Ag than with ITO. Previous studies have shown that smooth AFM images correspond to films that are homogeneous [38][39][40]. We therefore conclude that the PVK:CBP is likely not phase separated or aggregated.…”

Section: Microcavity Devicesmentioning

confidence: 68%

Deep blue/ultraviolet microcavity OLEDs based on solution-processed PVK:CBP blends

Hellerich

Manna

Heise

et al. 2015

Organic Electronics

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Keywords:UV-to-blue OLED arrays UV-to-blue microcavity OLED arrays PVK:CBP OLED arrays Polymer/small molecule mixed emission layer Ab initio simulations of OLED EL spectra a b s t r a c t There is an increasing need to develop stable, high-intensity, efficient OLEDs in the deep blue and UV. Applications include blue pixels for displays and tunable narrow solid-state UV sources for sensing, diagnostics, and development of a wide band spectrometer-on-a-chip. With the aim of developing such OLEDs we demonstrate an array of deep blue to near UV tunable microcavity (lc) OLEDs (k $373-469 nm) using, in a unique approach, a mixed emitting layer (EML) of poly(N-vinyl carbazole) (PVK) and 4,4 0 -bis(9-carbazolyl)-biphenyl (CBP), whose ITO-based devices show a broad electroluminescence (EL) in the wavelength range of interest. This 373-469 nm band expands the 493-640 nm range previously attained with lcOLEDs into the desired deep blue-to-near UV range. Moreover, the current work highlights interesting characteristics of the complexity of mixed EML emission in combinatorial 2-d lcOLED arrays of the structure 40 nm Ag/x nm MoO x /$30 nm PVK:CBP (3:1 weight ratio)/y nm 4,7-diphenyl-1,10-phenanthroline (BPhen)/1 nm LiF/100 nm Al, where x = 5, 10, 15, and 20 nm and y = 10, 15, 20, and 30 nm. In the short wavelength lc devices, only CBP emission was observed, while in the long wavelength lc devices the emission from both PVK and CBP was evident. To understand this behavior simulations based on the scattering matrix method, were performed. The source profile of the EML was extracted from the measured EL of ITO-based devices. The calculated lc spectra indeed indicated that in the thinner, short wavelength devices the emission is primarily from CBP; in the thicker devices both CBP and PVK contribute to the EL. This situation is due to the effect of the optical cavity length on the relative contributions of PVK and CBP EL through a change in the wavelength-dependent emission rate, which was not suggested previously. Structural analysis of the EML and the preceding MoO x layer complemented the data analysis.

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High‐Efficiency Solution‐Processed Small Molecule Electrophosphorescent Organic Light‐Emitting Diodes

Cited by 190 publications

References 58 publications

Electrically driven photon antibunching from a single molecule at room temperature

Electrically driven photon antibunching from a single molecule at room temperature

Nozzle Printed-PEDOT:PSS for Organic Light Emitting Diodes with Various Dilution Rates of Ethanol

Deep blue/ultraviolet microcavity OLEDs based on solution-processed PVK:CBP blends

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