Charged grain boundaries reduce the open circuit voltage of polycrystalline solar cells--An analytical description

Abstract

Analytic expressions are presented for the dark current-voltage relation $J(V)$ of a $p{n}^{+}$ junction with positively charged columnar grain boundaries with high defect density. These expressions apply to non-depleted grains with sufficiently high bulk hole mobilities. The accuracy of the formulas is verified by direct comparison to numerical simulations. Numerical simulations further show that the dark $J(V)$ can be used to determine the open circuit potential $V_{\mathrm{oc}}$ of an illuminated junction for a given short-circuit current density $J_{\mathrm{sc}}$ . A precise relation between the grain boundary properties and $V_{\mathrm{oc}}$ is provided, advancing the understanding of the influence of grain boundaries on the efficiency of thin film polycrystalline photovoltaics like CdTe and $\mathrm{Cu}(\mathrm{In},\mathrm{Ga})\mathrm{S}{\mathrm{e}}_2$.

14 pages, 10 figures

Cited by in corpus (1)

• Quantitative theory of the grain boundary impact on the open-circuit voltage of polycrystalline solar cells