文摘
We theoretically examine the light-to-electricity energy conversion in a molecular triad coupled to conducting leads. This coupling allows us to drive a current through the system. We derive the equations of motion for the electron density operators and determine the dependence of the current, quantum yield, and thermodynamic efficiency on temperature, the electrochemical potentials of the leads, as well as on the light intensity and frequency of the external electromagnetic field. For the molecular triad consisting of ferrocene, porphyrin, and fullerene molecules, we find that, in the case of relatively strong coupling to the leads, the power-conversion efficiency can exceed 40% and the quantum yield can be more than 90%, instead of the 25% quantum yield observed in experiments. Thus, this system is highly attractive for solar cell applications. The large predicted increase in the efficiency of this system is due to the stronger coupling to the contacts, which allows the triad to move more electrons through it, absorbing more photons per unit time, and doing more work.