Color map of the maximum concentration factor (logarithmic color scale) for different reflector absorption coefficient (1−R _back) and non-radiative loss probabilities (1−PLQY) at f = 10⁻⁶ and R _PSB = 1. Black curves are iso-concentration, the blue curve separates the two domains in which the PLQY loss is higher than R _back loss (upper domain) and reciprocally (lower domain). As a guide for the eye, the violet dashed curve represents a linear plot.