Optical efficiency enhancement in luminescent solar concentrators using a quasi-periodic reflector

The present paper aims to design a tunable polymeric multilayer dielectric reflector (PMD) to eliminate escape-cone effects in luminescent solar concentrators (LSCs). The PMD structure consisted of periodically and quasi-periodically stacked layers of polycarbonate (PC) and polymethyl methacrylate (PMMA). Monte Carlo and Transfer Matrix analysis demonstrated that the transmission band gap of a periodic reflector (PR) exhibited a narrow bandwidth and experienced a blue shift with increasing incident angles, resulting in a limited overlap with the dye emission band and inadequate capture of escape cone emissions. Conversely, the quasi-periodic reflector (QPR) achieved a broader transmission band gap, leading to complete overlap and higher efficiency. Furthermore, PMDs enhanced sunlight absorption in LSCs by reflecting transmitted solar photons through the LSC and increased reabsorption losses by minimizing escape cone losses. The results show optical efficiency of 12% and 33% for the LSC with PR and QPR, respectively. Additionally, investigations into optimal dye concentration revealed a change in concentration when PMDs are applied, allowing the system to select a lower optimal concentration to mitigate reabsorption losses.