Optimized Nanoparticle Alignment and Directional Emission for High-Efficiency Luminescent Solar Concentrators and Photonic Applications

Luminescent solar concentrators (LSCs) are a promising technology for enhancing solar energy harvesting by redirecting diffuse sunlight onto smaller, high-performance photovoltaic (PV) cells. However, conventional LSCs suffer from intrinsic limitations, including reabsorption losses and escape cone effects, which hinder their efficiency and practical applicability. To overcome these challenges, this study introduces a novel FunDiLight-LSC system, employing photostable nanodots as light-harvesting donors and aligned nanorods as light-redirecting acceptors. The system leverages Förster resonance energy transfer (FRET) to enhance energy absorption while minimizing reabsorption losses and directing fluorescence emission at optimized angles for total internal reflection. A detailed experimental and theoretical analysis is conducted to investigate energy transfer mechanisms, the impact of donor-acceptor ratios, and the alignment of nanorods. The results demonstrate that this nanoparticle-based LSC achieves energy transfer efficiencies exceeding 90%, with escape cone losses reduced to below 8%, significantly outperforming conventional organic dye-based LSCs. Furthermore, the superior photostability of the nanomaterials improves the durability and long-term applicability of the system. Additionally, this research explores the spatial orientation of core-crown CdSe/CdS nanoplatelets (NPLs) embedded in electrospun fibers using 3D single-particle polarized excitation microscopy. Based on the response of individual flat-lying NPLs to polarized light, the relationship between the distribution of transition dipole moments (TDMs) and NPLs’ spatial orientation is first established. By identifying the TDM orientation, the spatial orientation of arbitrary NPLs can then be determined. An unexpected perpendicular alignment of NPLs relative to the fiber direction is observed and further confirmed through polarized emission spectroscopy and 3D photogoniometry. The findings suggest that this alignment is driven by the Barus effect, where viscoelastic relaxation and normal forces during electrospinning dictate the final orientation of NPLs. By systematically adjusting fiber fabrication parameters, multiple NPL orientation modes are achieved, including randomly oriented, vertically aligned parallel to the fiber direction, vertically aligned perpendicular to the fiber direction, and mixed orientations. These results not only provide a new method to analyze the NPL orientation but also establish a new approach for optimizing the optical performance of luminescent materials. This study investigates emissive nanosemiconductors with exceptional optical properties, focusing on achieving controlled directional emission through precise alignment. The integration of nanodots and nanorods enables a photostable and efficient LSC system optimized for GaInP tandem PV layers, offering a practical approach to improving solar energy harvesting. The controlled alignment of NPLs further broadens their applicability in photonic and optoelectronic systems. These findings enhance the understanding of nanomaterial alignment and energy transfer, contributing to advancements in optoelectronic devices and photovoltaic technologies.