Effects of carrier mobility, energy gap, and excitation size on the performance of single layer organic solar cells

Abstract

A model of universal single layer organic solar cells in metal-insulator-metal (MIM) representation involving field-dependent carrier mobility is set up. The current-voltage characteristics as well as the distribution of electron density, hole density and recombination rate on a set of parameters are simulated. Subsequently, the dependences of the short-circuit current density (J_sc) and open-circuit voltage (V_oc) on the electron and hole zero-field mobility, excitation generation rate, energy gap, as well as electron-hole pair distance in an excitation are investigated. It is demonstrated that the enhancement of either the electron mobility or the hole mobility can contribute to the increase of J_sc in the devices. The increase of the hole mobility can lead to the improvement of both J_sc and V_oc, and the simultaneous increase of the electron mobility and hole mobility will greatly elevate J_sc but maintain a steady V_oc. Additionally, all the increases of the excitation generation rate, energy gap and electron-hole pair distance are beneficial to both the remarkable increases of J_sc and V_oc of the devices.

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