Semi-Empirical Limiting Efficiency of Singlet-Fission-Capable Polyacene/Inorganic Hybrid Solar Cells

A detailed balance limiting efficiency calculation of a singlet fission capable organic/inorganic hybrid solar cell is presented. Incorporating experimental values for pertinent rates in the organic layer we find that the limiting efficiency of a tetracene/ideal inorganic semiconductor cell is 35.8%, exceeding the Shockley–Queisser limit. We further propose an “equivalent circuit” model of excitonic current, with three “cells” corresponding to the organic, inorganic, and interface species. By considering their relative contributions to the current density of the device, we discuss the major loss mechanisms and identify that the triplet lifetime and nonradiative decay of bound polaron pairs are major limitations to the development of a high-efficiency polyacene/inorganic solar cell. The results suggest that the efficiency of a tetracene/silicon hybrid solar cell could exceed the Shockley–Queisser limit.