Light management for photovoltaics using multi-size QD arrays

In this study, we present a new approach to increase the spectral response of a silicon solar cell by exploiting the size-dependent refractive index of quantum dots. Compared to a conventional luminescent downshifting layer (LDS), our LDS design allows for thicker films and thus a higher optical absorption at the LDS layer while the reflectance is reduced. Our simulations demonstrate that a multi-size QD design outperforms the optimum single-size structure by reducing the average reflectance from 5.85% to 2.63% and increasing the total thickness from 82 nm to 138 nm when compared to the latter.