Hole mobility in optimized organic photovoltaic blend films obtained using extraction current transients

Kumar, Ankit; Liao, H.H.; Yang, Yang

doi:10.1016/j.orgel.2009.08.003

Cited by 37 publications

(22 citation statements)

References 30 publications

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“…90 Dennler et al reported the determination of hole mobilities in blend films of PCBM and a PPV derivative. 95 96 The nature of the transient peaks was correlated with the fill factor of the BHJSCs, and it was reported that for the blend films with balanced hole and electron mobilities highest fill factors were obtained. Tolbert et al utilized photo-CELIV technique for determining the cause of a ''S''-shaped current-voltage (J-V) behavior usually observed in low-performance BHJSCs.…”

Section: Reviewmentioning

confidence: 99%

Techniques for characterization of charge carrier mobility in organic semiconductors

Kokil

Yang

Kumar

2012

J Polym Sci B Polym Phys

151

128

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The charge transport characteristics of organic semiconductors are one of the key attributes that impacts the performance of organic electronic and optoelectronic devices in which they are utilized. For improved performance in organic photovoltaic cells, light-emitting diodes, and field-effect transistors (FETs), efficient transport of the charge carriers within the organic semiconductor is especially critical. Characterization of charge transport in these organic semiconductors is important both from scientific and technological perspectives. In this review, we shall mainly discuss the techniques for measuring the charge carrier mobility and not the theoretical underpinnings of the mechanism of charge transport. Mobility measurements in organic semiconductors and particularly in conjugated polymers, using space-charge-limited current, time of flight, carrier extraction by linearly increasing voltage, double injection, FETs, and impedance spectroscopy are discussed. The relative merits, as well as limitations for each of these techniques are reviewed.

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Section: Reviewmentioning

confidence: 99%

Techniques for characterization of charge carrier mobility in organic semiconductors

Kokil

Yang

Kumar

2012

J Polym Sci B Polym Phys

151

128

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“…Increasing the PCBM ratios makes the device more resistant to changes in fi ll factor. High fi ll factors have been attributed to balance of mobility [ 9 ] of the two carriers in the device. Ideal diodes (with diode ideality factor ( n ) = 1) should have fi ll factors up to 86%.…”

Section: Photovoltaic Device Performancementioning

confidence: 99%

Origin of Radiation‐Induced Degradation in Polymer Solar Cells

Kumar

Devine

Mayberry

et al. 2010

Adv Funct Materials

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Polymer solar cells have been shown to degrade under X‐rays. Here, in situ polymer photovoltaic performance and recombination lifetimes are measured and it is found that charge accumulation is the primary reason for degradation of solar cells. This is affected by the mixing ratio of donor and acceptor in the bulk heterojunction. Both a quantitative understanding and the physical model of the degradation mechanism are presented. Understanding of the degradation mechanism is extended in polymer donor–acceptor bulk heterojunction systems to propose a material combination for making radiation hard diodes that can find important application in fields ranging from memory arrays to organic X‐ray detectors for medical imaging.

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“…[ 43,44 ] A 510 nm dye laser (LSI DUO-220) pumped by a nitrogen laser (LSI VSL-337ND-S) was used as the excitation source. The pulse energy and pulse width were about 3 μ J/cm2 and 4 ns, respectively.…”

Section: Photo-charge Extraction By Linearly Increasing Voltage (Photmentioning

confidence: 99%

The Critical Role of Processing and Morphology in Determining Degradation Rates in Polymer Solar Cells

Kumar¹,

Hong²,

Sista³

et al. 2010

Advanced Energy Materials

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With rapid increase in the efficiencies of polymer solar cells (PSCs) in the last few years, the issue of device stability is taking center stage in organic photovoltaic research. In this work, the effects of oxygen and light on the degradation of charge‐transport properties of the bulk polymer active layer are studied over short timescales. It is shown that although different processing techniques produce similar efficiencies for pristine devices, they result in different degradation rates. This variation in degradation rates is primarily due to slightly different morphology parameters, such as molecular packing or disorder in the film. Investigation reveals that the choice of processing for the devices should consider degradation rates as a critical parameter, not just the efficiencies of the pristine devices. It was found that degradation starts with broadening of the effective density of states due to photo‐oxidation. Both transient absorption and charge extraction by linearly increasing voltage (CELIV) measurements show increase in disorder in the films with progressive degradation. It is suggested that annealing provides the necessary thermal energy to reduce the trap states by flattening out the energy landscape of the pristine films, improving not only the efficiency, as reported previously, but also slowing the degradation rates.

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Hole mobility in optimized organic photovoltaic blend films obtained using extraction current transients

Cited by 37 publications

References 30 publications

Techniques for characterization of charge carrier mobility in organic semiconductors

Techniques for characterization of charge carrier mobility in organic semiconductors

Origin of Radiation‐Induced Degradation in Polymer Solar Cells

The Critical Role of Processing and Morphology in Determining Degradation Rates in Polymer Solar Cells

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