Efficiency of a laterally engineered architecture for photovoltaics

An array of photovoltaic (PV) cells is proposed for use in conjunction with a diffractive optical element as an economical and efficient approach to terrestrial photovoltaics. In this work, the sensitivity of the array efficiency to the distribution of the incident spectrum over the cells is discussed. Optimal distributions are specified for 2-, 3-, and 4-segment partitions of the incident spectrum using a detailed balance analysis. Maximum efficiencies for lateral arrays of 2, 3 and 4 cells are found by the same means. At 1 sun, these are 42.7%, 48.4% and 52.0%, respectively. At 100 suns they increase to 48.6%, 54.8% and 59.1%. The sensitivity of the efficiency of an optimal array to spectral variation is discussed. Electrical isolation of cells using power electronics circuitry is found to yield an efficiency gain of at least 27.3% over the series connection of cells in the array.