Luminescent solar concentrators (LSCs) provide a transformative approach to integrating photovoltaics into a built environment. In this paper, we report thin-film LSCs composed of intramolecular charge transfer fluorophore (DACT-II) and discuss the effect of two polymers, polymethyl methacrylate (PMMA), and poly (benzyl methacrylate) (PBzMA) on the performance of large-area LSCs. As observed experimentally, DACT-II with the charge-donating diphenylaminocarbazole and charge-accepting triphenyltriazine moieties shows a large Stokes shift and limited re-absorption losses in both polymers. Our results show that thin-film LSC (10 × 10 × 0.3 cm3) with optimized concentration (0.9 wt%) of DACT-II in PBzMA gives better performance than that in the PMMA matrix. In particular, optical conversion efficiency (ηopt) and power-conversion efficiency (ηPCE) of DACT-II/PBzMA LSC are 2.32% and 0.33%, respectively, almost 1.2 times higher than for DACT-II/PMMA LSC.

Crystallization engineering is crucial for the preparation of drug delivery systems with precise release behavior and improved stability. Although evaporation has been commonly used to prepare pharmaceutical film formulations, controlled evaporative crystallization to achieve uniform crystal size and shape has rarely been investigated. In this study, ordered submicrometer composite structures of acetaminophen (ACM) and polymers were prepared via directional evaporative crystallization controlled by a temperature gradient. The ACM crystals had submicrometer sizes while retaining the original crystal polymorph and were aligned along the direction of the temperature gradient, resulting in line structures having branches with uniform and oriented crystal structures. Although the use of a polymer did not affect conventional oven-crystallized films, it significantly decreased the melting point and heat of fusion of directionally crystallized films. The formation of ordered submicrometer composite structures must rely more on kinetic parameters than thermodynamic parameters since no significant intrinsic molecular interactions were discovered. A wide range of sustained-release characteristics could be obtained depending on the polymer types. This unique fast directional crystallization method could offer a new opportunity for future film delivery systems.

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