Antonio Alfredo Andrade Chepluki

In this work, large-area tandem laminated double-layer luminescent solar concentrators (LSCs) based on blue-emitting and orange-emitting pyrene-derived graphitized carbon quantum dots (CQDs) dispersed in an ethylene–vinyl acetate (EVA) matrix were fabricated and systematically investigated. The optical properties and outdoor photovoltaic performance of the individual LSCs were evaluated and compared with those of the tandem architecture. The orange-emitting LSC exhibited a larger Stokes shift (≈135 nm) than the blue-emitting LSC (≈80 nm), indicating reduced spectral overlap and, consequently, lower self-absorption losses. Outdoor exposure revealed excellent short-term stability for the blue-emitting LSC, whereas the orange-emitting LSC exhibited a progressive decline in photovoltaic performance. The tandem architecture broadened the spectral harvesting range, achieving a maximum optical efficiency of 8.09% and a power conversion efficiency of 0.306% when illuminated from the orange-emitting LSC side. These results highlight tandem integration of spectrally complementary luminescent materials as a promising strategy for broadening solar-spectrum utilization and improving the optical and photovoltaic performance of LSCs, with potential for application in building-integrated photovoltaics (BIPVs).

Improving the efficiency and long-term stability of luminescent solar concentrators (LSCs) remains a challenge for their practical application in building-integrated photovoltaics (BIPV). In this work, laminated LSCs based on a blue-emitting resin and orange-emitting dispersed in an ethylene-vinyl acetate (EVA) matrix were fabricated and systematically investigated. The optical properties, distance-dependent photon propagation, photovoltaic performance, and short-term outdoor stability of the individual LSCs were evaluated and compared with those of tandem architecture. The orange-emitting LSC exhibited a larger Stokes shift (≈135 nm) than the blue-emitting resin LSC (≈80 nm), indicating reduced spec-tral overlap and lower self-absorption losses. Outdoor exposure demonstrated excellent short-term stability for the blue-emitting resin LSC, whereas the orange-emitting device ex-hibited a progressive decline in photovoltaic performance. The tandem architecture broadened the spectral harvesting range, achieving a maximum optical efficiency of 8.09%, a power conversion efficiency of 0.306%, a short-circuit current density of 0.283 mA cm⁻², an open-circuit voltage of 1.9 V, and a fill factor of 56.7% when illuminated from the or-ange-emitting LSC side. These findings demonstrate that combining spectrally comple-mentary luminophores in tandem architecture is an effective strategy for broadening solar spectrum utilization and enhancing the optical and photovoltaic performance of LSCs for BIPV applications.

The biospeckle laser (BSL) technique is recognized as a sensitive method for detecting biological activity and has been successfully applied for seed vigor testing. Given these achievements, whether the integration of BSL into automated systems can provide complementary information on the seed imbibition process remains limited. Addressing this gap represents a significant challenge with strong potential for technological innovation. This study presents an automated laser-optical system designed to monitor the imbibition process of multiple seeds over time using a mechanized carousel. The developed apparatus integrates all necessary components for the illumination and image acquisition of eight seeds across programmable time intervals, controlled by an industrial-grade programmable controller. Validation using maize seeds (Zea mays L.) over a 36-h period confirmed the system’s reliability. BSL indices enabled the characterization of internal biological activity throughout imbibition, revealing dynamic processes that remained undetected in previous discrete-time analyses. These results highlight the potential of the proposed system for more comprehensive and continuous seed monitoring. The successful automated laser-optical system with relative humidity control opens great potential in seeds research and daily industrial analysis. The test of the proposed system in other seeds is the next challenge, regarding the thick and colored coats. The design of larger carousels is a possible step forward, which will demand studies of the limits linked to the illumination and image acquisition time performed in each seed.