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Power Dependence and Turn-On Dynamics of Polymer Photocells - Extracting Mobilities and Analyzing Morphologies

Published online by Cambridge University Press:  01 February 2011

Noam Rappaport
Affiliation:
Electrical Engineering Faculty, Technion Israel Institute of Technology, Haifa, Israel.
Nir Tessler
Affiliation:
Electrical Engineering Faculty, Technion Israel Institute of Technology, Haifa, Israel.
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Abstract

We present an analytic description for the loss of photocurrent efficiency at moderate light intensities and demonstrate a simple technique for extracting the mobility of electrons in semiconducting polymer layers. The underlying theoretical analysis, which is based on a simple drift-recombination scheme, shows good agreement with the measured intensity dependent photocurrent quantum efficiency. The electron mobility extraction is demonstrated for pristine MEH-PPV. The same physical framework is then used to describe the switch on of the photocurrent and the buildup of electron and hole concentrations inside the device. By analyzing the time evolution of the measured photocurrent transient we find an independent verification for the results extracted from the intensity dependence measurements. We use the combination of theoretical and experimental study to discuss the role recombination and space charge effects in reducing photocurrent efficiency.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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References

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