Pulsed magnetic resonance of Alq3 OLED detected by electroluminescence

Comandè, Francesco; Ansermet, Jean-Philippe

doi:10.1016/j.synthmet.2012.12.037

Cited by 4 publications

(5 citation statements)

References 22 publications

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“…This method allowed us to estimate the effect of the space charge reaction time directly on the electroluminescence and confirm the conclusions reported in Ref. [22].…”

supporting

confidence: 86%

“…Similarly to what was already shown by Li and coworkers using continuous wave ELDMR, at low temperature the resonance changes sign, resulting in an enhancement of the electroluminescence [23]. Contrary to bias voltage [22], temperature has a net effect on the resonance dynamics. The time needed to restore the electroluminescence equilibrium increases with decreasing temperature.…”

supporting

confidence: 69%

“…This differs from the setup reported in Ref. [22] in the presence of an optical cryostat, cooled by a continuous flow of liquid helium. Also, a traveling wave tube microwave amplifier is used to amplify the microwave pulses.…”

mentioning

confidence: 61%

“…In particular, the group of Wohlgenannt detected an intrinsic cutoff frequency for spin processes of 10 kHz in Alq 3 OLEDs. Recently, we proposed a way to explore spin dynamics in OLEDs by using pulsed electroluminescence detected magnetic resonance (PELDMR) [22]. PELDMR is particularly useful in systems such as OLEDs as it gives the opportunity to study spin processes while the device is operating, reproducing the same experimental conditions of most OMAR studies [3,4].…”

mentioning

confidence: 99%

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Time-resolved spin processes inAlq3light-emitting diodes

Comandè

Ansermet

2014

Phys. Rev. B

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Using pulsed electroluminescence detected magnetic resonance (PELDMR), we study the dynamics of spin processes in Alq 3 based light-emitting diodes. The transitions induced by magnetic resonance are found to be much faster than the space charge reaction time that is measured by looking at the electroluminescence frequency response to an ac bias voltage. This observation excludes a change in the equilibrium space charge distributions as the cause of PELDMR, in favor of a change of the electron-hole recombination rate. At low temperatures the effect of electron spin resonance on the electroluminescence changes sign and lasts longer. The postpulse electroluminescence recovery is well fitted by a biexponential function characterized by two very different time scales, which are consistent with a detailed balance for the singlet and triplet states, in conformity with the electron-hole pair model.

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“…This method allowed us to estimate the effect of the space charge reaction time directly on the electroluminescence and confirm the conclusions reported in Ref. [22].…”

supporting

confidence: 86%

supporting

confidence: 69%

mentioning

confidence: 61%

mentioning

confidence: 99%

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Time-resolved spin processes inAlq3light-emitting diodes

Comandè

Ansermet

2014

Phys. Rev. B

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“…Alq 3 organic material is considered to be one of the most remarkable organic materials due to being environmentally friendly, electrically high resistance, being produced at low temperatures and stability compared with many known oxide films. In addition to these, it has become a widely selected material in organic light emitting diodes due to its low molecular weight, strong luminescence properties and low cost, and it is also used as the base material for various dyes to adjust the emission color from green to red [16][17][18]. There are many studies on the optical, structural, morphological, and photoluminescence properties of the synthesized Alq 3 film [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Frequency and voltage dependence of electrical conductivity, complex electric modulus, and dielectric properties of Al/Alq3/p-Si structure

Orak¹,

Karabulut²

2020

Turk J Phys

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In order to enhance the capacitance of the Al/p-Si metal-semiconductor structure, the Alq 3 thin film was coated between these two layers using the spin coating technique as the interlayer. The electrical conductivity, real and imaginary parts of electric modulus, dielectric loss and dielectric constant parameters were examined at the room temperature by the help of admittance measurements in the 100 kHz to 1 MHz frequency range. The effect of frequency on the dielectric constant and dielectric loss values is negligible at the negative voltage values, up to about 0.8 V, and these values rapidly ascended after 0.8 V. The function of electrical modulus complex has been examined from the point of permittivity and impedance in order to clutch the contribution of the particle border on the relaxation mechanism of the materials. It is established that the examined dielectric parameters strongly correlated with the voltage and frequency. As a result, the changes in the dielectric parameters and electrical modulus due to the varying frequency were described as the results of relaxation process, polarization and surface conditions. Furthermore, it could be stated that the Alq 3 material used in the interfacial layer is a useful material which could be used in addition to the conventional materials.

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