Optical center of a luminescent solar concentrator.

This Letter introduces a novel, to the best of our knowledge, approach to estimate the power conversion efficiency (PCE) of a square luminescent solar concentrator (LSC) by point excitations on the "optical centers." Predicted by theoretical calculations, photoluminescence emissions from these optical centers experience almost the same average optical path as those from the whole device under uniform illumination. This is experimentally verified by a 20 × 20 cm silicon quantum dot-based LSC, with a negligible error between the predicted PCE and the measured one. This method provides a convenient way to estimate the photovoltaic performance of large-area LSC devices with basic laboratory instruments.