Thickness dependence of space charge limited current and injection limited current in organic molecular semiconductors

Agrawal, Ruchi; Kumar, Pramod; Ghosh, Subhasis; Mahapatro, Ajit K.

doi:10.1063/1.2974084

Cited by 59 publications

(26 citation statements)

References 18 publications

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“…Because, it has been shown that if the barrier at metal/organic interface is more than 0.3 eV, current transport is due to injection limited current, where the electric field is nearly uniform, and traps effects in organic layers are not important [14]. Also, for PbSe QDs we find the energy levels well aligned inside the organic materials used (see Fig.…”

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confidence: 70%

Electronic and excitonic processes in multilayer organic light emitting devices incorporating PbSe quantum dots

2011

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In this work we investigate the operation mechanism of hybrid organic/inorganic quantum dot light emitting devices (QD-LEDs). We employ a numerical method previously established to describe current-voltage characteristics, spatial distributions of charge, electric field, and recombination rate in organic light emitting devices (OLEDs). The numerical solution of the continuity and Poisson equations have been extended to treat internal organic/Quantum Dot (QD) interfaces, recombination processes in the polymer matrix and in the QDs, and the charge acquired by the QDs. The contact boundary condition is taken to be Schottky contact boundary condition. Also, we consider the exciton formation and diffusion processes. The simulation results trend and experimental data are in good agreement.

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confidence: 70%

Electronic and excitonic processes in multilayer organic light emitting devices incorporating PbSe quantum dots

2011

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“…4(b) shows the J-V characteristics of ITO/CuPc/Au based two terminal devices in which CuPc thin lms were grown at T G ¼ 120 C. Initially, the current increases linearly in this device, but as the bias increases, injected carrier density exceeds the intrinsic free carrier density and current follows SCLC. 34,35 SCLC is observed when there is either no or very low density of traps. In SCLC regime, slope starts from 2 and eventually increases with bias due to the eld dependent carrier mobility m(F,T), given by 36…”

Section: Arrangement Of Molecules In Cupc Thin Filmsmentioning

confidence: 99%

“…,T]F(x) simultaneously. 34 Upper inset of Fig. 4(b) shows the TSCAP measurements of the corresponding device.…”

Section: Arrangement Of Molecules In Cupc Thin Filmsmentioning

confidence: 99%

Charge transport mechanism in copper phthalocyanine thin films with and without traps

et al. 2017

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We investigate the charge transport mechanism in copper phthalocyanine thin films with and without traps. Previously, charge transport in polycrystalline thin films has been widely described by the multiple trapping and release (MTR) model, without emphasizing the origin of the traps. In this work, polycrystalline organic thin films with and without traps have been grown by engineering different growth conditions. We find that the density of interface states at the grain boundaries can decide the mechanism of charge transport in organic thin films and completely different charge transport mechanisms can be observed in thin films with and without traps.

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“…Agrawal et al [23] compared injection-limited currents and SCL currents in a copper-phthalocyanine sandwich cell with ITO and Al electrodes. An analysis of experimental data yields consistent values for the width of the DOS distribution as well as for inter-site separation.…”

Section: Box 33 Arrhenius Plotmentioning

confidence: 99%

Electronic and Optical Processes of Organic Semiconductors

Köhler

Bäßler

2015

Electronic Processes in Organic Semiconductors

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Semiconductors are, by definition, materials that are intended for use in optoelectronic devices. The most common applications of organic semiconductors encompass organic light-emitting diodes (OLEDs), organic solar cells (OSCs), and organic field-effect transistors (OFETs) (Figure 3.1).In essence, an OLED is made in a sandwich-type structure by covering a substrate sequentially with a bottom electrode, the active semiconducting material and a top electrode. Upon applying a voltage, positive and negative charges are injected from the electrodes into the semiconductor and move through it. While a part of these charges may leave the organic film at the counter electrode, having resulted in nothing but dissipated heat, some of the electrons and holes will encounter and capture each other to form an excited state that may recombine with or without light emission. The processes involved in the operation of an OLED are illustrated in Figure 3.1, along with the processes relevant for an OSC. The OSC has, in principle, the same structure as that of an OLED; yet, it operates in the reverse direction. Light is absorbed and creates excited states. Some of these states may eventually dissociate into free, mobile positive and negative charges that move to opposite electrodes where they are collected to yield a current. The photophysical mechanisms associated with OLEDs and OSC operation, such as charge injection, charge transport, electron-hole recombination, and excited state dissociation are discussed in detail in the corresponding sections of this chapter. Also included are processes relating to the excited states such as energy transfer and decay mechanisms. Issues pertaining to the fabrication, operation, characterization, and optimization of the entire device are considered in the next chapter. The same approach of chapter organization is taken concerning the OFET. The fabrication and operation of the OFET is detailed in Chapter 4, whereas this chapter covers, inter alia, the process of charge transport for the regimes of low and high charge carrier density.The generic structure of an OFET differs from the OLED/OSC structure. An OFET contains three electrodes in contrast to the two electrodes of the OLED/OSC layout. In the OFET, two electrodes, the source and the drain electrode, are separated by the active semiconductor. When a voltage is applied between the source and the drain electrode, current can, in principle, flow between them. The amount of current that flows is controlled by the third, the gate electrode that is separated from the active semiconductor by an insulator layer. If there is no voltage applied to the gate electrode, the current flow between the source and the drain is negligibly small, even when there is a potential difference between the source and the drain. The reason for this lies in the high resistivity of the organic semiconductor in combination with the device geometry. In an OLED, the electrodes are separated only by 100 nm of semiconductor, and the electrodes cover most of the semiconductor...

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Thickness dependence of space charge limited current and injection limited current in organic molecular semiconductors

Cited by 59 publications

References 18 publications

Electronic and excitonic processes in multilayer organic light emitting devices incorporating PbSe quantum dots

Electronic and excitonic processes in multilayer organic light emitting devices incorporating PbSe quantum dots

Charge transport mechanism in copper phthalocyanine thin films with and without traps

Electronic and Optical Processes of Organic Semiconductors

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