Many experimental measurements have been done on GNR conductance. In this paper, analytical model of GNR conductance is presented. Moreover, comparison with published data which illustrates good agreement between them is studied. Conductance of GNR as a one-dimensional device channel with parabolic band structures near the charge neutrality point is improved. Based on quantum confinement effect, the conductance of GNR in parabolic part of the band structure, also the temperature-dependent conductance which displays minimum conductance near the charge neutrality point are calculated. Graphene nanoribbon (GNR) with parabolic band structure near the minimum band energy terminates Fermi-Dirac integral base method on band structure study. While band structure is parabola, semiconducting GNRs conductance is a function of Fermi-Dirac integral which is based on Maxwell approximation in nondegenerate limit especially for a long channel.
Integration of light-trapping features and exploitation of metal nanostructure plasmonic effects are promising approaches for enhancing the power conversion efficiency of organic solar cells. These approaches’ effects on the light absorption enhancement have been widely studied, especially in inorganic devices. While this light-trapping concept can be transferred to organic devices, one has to also consider nanostructure-induced electrical effects on the device performance, due to the fundamental difference in the organic semiconducting material properties compared to their inorganic counterparts. In this contribution, we exemplarily model the electrical properties of organic solar cells with rectangular-grating structures, as compared to planar reference devices. Based on our numeric results, we demonstrate that, beyond an optical absorption enhancement, the device fill factor improves significantly by introducing the grating structures. From the simulations we conclude that enhanced carrier collection efficiency is the main reason for the increased solar cell fill factor. This work contributes towards a more fundamental understanding of the effect of nanostructured electrodes on the electrical properties of organic solar cells.
The aim of this work is to present a consistent model for simulation of organic solar cells (OPV) with a correct description of mobility, density of state, organic-metal contacts, and exciton. We simulate the photoconversion by means of an integration of the optical and electrical part: light absorption is calculated with a Transfer Matrix Model and the charge transport is computed using Drift Diffusion approach including the effect of energetically disorder materials. Most model parameters are directly taken from experiment. The model is used to study the effect of energetic disordered materials and cell thickness on the performance of the cell in terms of short circuit current, open circuit voltage, and fill factor. Based on the results of this model, it will be possible to design and predict the optimal thickness of OPV toward higher efficiencies. (C) 2014 AIP Publishing LLC
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