Correlated electron dynamics in quantum-dot sensitized solar cell: Kadanoff-Baym versus Markovian approach

Abstract

Electron dynamics in quantum-dot sensitized solar cells is studied in the nonequilibrium Green's function approach. To solve Kadanoff-Baym (KB) equations we propose a method based on two-time spectral expansion of nonequilibrium Green's functions. The method is very efficient for stationary photocurrent calculations. The calculated photocurrent is compared with the computations based on the Markovian master equations. It is shown that the Markovian approximation overestimates the photocurrent versus the numerical solutions of the exact KB equations. The discrepancy can reach as much as one order of magnitude and, therefore, the Markovian approximation can overestimate the solar cell efficiency by one order of magnitude.