Groves, C. and Koster, L.J.A. and Greenham, N.C. (2009) 'The effect of morphology upon mobility : implications for bulk heterojunction solar cells with nonuniform blend morphology.', Journal of applied physics., 105 (9). 094510.
We use a Monte Carlo model to predict the effect of composition, domain size, and energetic disorder upon the mobility of carriers in an organic donor-acceptor blend. These simulations show that, for the changes in local morphology expected within the thickness of a typical bulk heterojunction photovoltaic device, changes in mobility of more than an order of magnitude are expected. The impact of nonuniform mobility upon space-charge-limited diode and photovoltaic (PV) device performance is examined using a drift-diffusion model. The current passing through a space-charge-limited diode is shown to depend upon the position of the layers with differing mobility. Accurate modeling of the current in such devices can only be achieved using a drift-diffusion model incorporating nonuniform mobility. Inserting a 20 nm thick layer in which the mobility is less by one order of magnitude than in the rest of the 70 nm thick PV device reduced the device efficiency by more than 20%. Therefore it seems vital to exert a high degree of control over the morphology throughout the entire blend PV device, otherwise potential PV performance may be lost.
|Keywords:||Thin-films, Poly(p-phenylene vinylene), Photocurrent Generation, Charge-transport, Hole transport, Polymer blends, PCBM blends, MDMO-PPV, Performance, Photodiodes.|
|Full text:||(VoR) Version of Record|
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|Publisher Web site:||http://dx.doi.org/10.1063/1.3117493|
|Publisher statement:||Copyright 2009 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Groves, C. and Koster, L.J.A. and Greenham, N.C. (2009) 'The effect of morphology upon mobility : implications for bulk heterojunction solar cells with nonuniform blend morphology.', Journal of applied physics., 105 (9). 094510 and may be found at http://dx.doi.org/10.1063/1.3117493|
|Date accepted:||No date available|
|Date deposited:||09 March 2011|
|Date of first online publication:||May 2009|
|Date first made open access:||No date available|
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