• Energy Research

Abstract Luminescent solar concentrators (LSCs) harvest solar radiation over large areas and concentrate this light onto edge-mounted solar cells. Here, we demonstrate that the addition of cylindrical optical fibers, along with a white scattering layer on the bottom side of the LSC, has a significant positive impact on the energy output of the LSC system. We show that the increased energy output is due to the additional light trapping modes provided by the array of cylindrical optical fibers. Moreover, we experimentally determine that the use of cylindrical optical fibers is more effective in the case of large size LSC. In addition, the photovoltaic response of our prepared devices is obtained, and the results reveal that the power conversion efficiency of the LSC containing cylindrical optical fibers along with a white scattering layer is ∼65% more than that of the LSC with a black absorbing layer, and ∼3.3% more than that of the LSC with only a white scattering layer.

Abstract The use of luminescent solar concentrators (LSCs) is considered a promising solution for harvesting indoor and outdoor light energy. Despite a multitude of investigations of LSC based photovoltaic (PV) systems, few reports are available on LSCs for emerging PVs, such as third-generation PV technologies. To fill this gap, we develop a novel LSC based PV device by coupling an LSC with a low-cost organic solar cell. The LSC is fabricated by employing different concentrations of organic luminophores, while a polymer/fullerene-based photoactive layer is prepared for the organic PV (OPV) device. With proper spectral matching, our champion LSC-OPV device exhibits optical efficiency (ηopt) and power conversion efficiency (ηPCE) of 6.10% and 0.51% under light-emitting diode (LED) illumination, respectively. Further, performance evaluation under 1sun illumination implies the ηopt and ηPCE of 8.5% and 0.17%. We also perform the color analysis of LSC-OPV devices which shows that such devices are aesthetically feasible for use in indoor and outdoor conditions. Thus, this study highlights the substantial opportunity for the rational design of hybrid LSC-PV systems where third-generation PVs are viable prospects.

Fair and meaningful device per- formance comparison among luminescent solar concentrator- photovoltaic (LSC-PV) reports cannot be realized without a gen- eral consensus on reporting stan- dards in LSC-PV research. There- fore, it is imperative to adopt standardized characterization protocols for these emerging types of PV devices that are consistent with other PV devices. This commentary highlights several common limitations in LSC literature and summarizes the best practices moving for- ward to harmonize with standard PV reporting, considering the greater nuances present with LSC-PV. Based on these prac- tices, a checklist of actionable items is provided to help stan- dardize the characterization/re- porting protocols and offer a set of baseline expectations for au- thors, reviewers, and editors. The general consensus combined with the checklist will ultimately guide LSC-PV research towards reliable and meaningful ad- vances.

Abstract The ability of polymer dispersed liquid crystals (PDLC) smart window to electrically control the visible and near-infrared light transmissions aids to reduce the artificial lightning, heating and cooling loads in the built environment. This study presents a complementary coupling of nitrogen-doped carbon quantum dot (N-CQDs) based waveguide with PDLC smart window device that selectively harvests the ultraviolet light (UV) and near UV light for electrical energy generation without competing for the visible and near-infrared light. The hybrid device can be switchable between transmissive and opaque light scattering state while simultaneously generating electrical energy. Spectral characteristics of the light transmitted through the device confirm that UV photons are completely harvested while most of the visible and near-IR photons are transmitted. The colorimetry analysis of waveguide-coupled PDLC devices is done to realize their compatibility with visual comfort of individuals residing in the building with such windows. We eventually demonstrate that strong scattering effect during the OFF state of waveguide-coupled PDLC device is responsible for its improved optical and power efficiencies (~ 4.52% and ~ 2. 49% respectively) as compared to that in the ON state of PDLC.

Abstract Harvesting solar energy through the use of luminescent solar concentrators is an attractive route to meet the world’s growing energy demands. In this study, we present an effective approach aimed at enhancing the edge emissions of luminescent solar concentrator based on stacking two waveguides, each containing a discrete set of metal nanoparticles (NPs) and organic luminophores. It is experimentally demonstrated that a stacked structured plasmonic luminescent solar concentrator (SPLSC) allows the light harvesting over a broad spectral range, while at the same time effectively exploits the plasmonic properties of silver and gold NPs leading to increased edge emissions. The results show a continuous transition from emission enhancement to quenching, depending on the luminophore-NPs distance (governed by NPs concentrations) in the SPLSC. Moreover, it is revealed that the NPs size also affects the edge emission of SPLSC. Edge emission measurements show SPLSC containing 20 nm silver and gold NPs give the maximum power efficiency which is almost 1.7 times more than that of simple stacked LSC without NPs. Photocurrent measurements are also performed as an additional evidence for the improved performance of SPLSC samples.

Abstract In this study, we demonstrate the simultaneous use of carbon quantum dots and organic dyes as highly emissive luminescent material in high performance tandem luminescent solar concentrator (LSC). The top LSC layer is based on carbon quantum dots (CQDs), while the bottom one is based on organic dye. The role of forster resonance energy transfer (FRET) is demonstrated in organic dyes in a bottom LSC. Moreover, the CQDs layer which has the capability to harvest ultraviolet (UV) and near-UV photons acts as a protective layer to improve the photo-stability of the organic dyes contained in bottom waveguide. The electrical measurements showed that the optical conversion efficiency (ηopt) and power conversion efficiency (ηPCE) of CQDs based single LSC are 5.62% and 1.03% respectively. While, ηopt, and ηPCE the dye-LSC are 13.42% and 2.72% respectively. However, in the tandem LSC, overall ηopt and ηPCE are 16.32% and 3.2% respectively. Our results showed that tandem structured CQDs and dye based luminescent solar concentrators make the practical use of LSCs more feasible because of the unique properties such as good photostability and high efficiency.