Inorganic and Organic Nano-Emitters for Luminescent Solar Concentrators
Authors: Benetti Daniele , Rosei Federico 
Published: May 2020

Generating power directly from solar radiation represents a promising opportunity towards addressing the increasing demand for clean energy, also reducing environmental impact caused by excessive carbon emissions. Luminescent solar concentrators (LSCs) are being widely studied as fluorophore-containing waveguides to harvest solar energy in combination with photovoltaic (PV) technologies, due to their low cost and straightforward synthesis by wet chemical approaches. LSCs can play an important role in the emerging building-integrated photovoltaic (BIPV) industry as they provide a low cost alternative to transparent solar cell. 1-4 Typical LSCs consist of optical waveguides doped with highly emissive fluorophores which are required to exhibit high optical efficiency and long-term stability. Among various types of luminescent particles suitable for LSCs, inorganic quantum dots (QDs) are excellent candidates because they offer several advantages, including high good quantum yield (QY), size-tunable absorption/emission, better chemical-/photo-stability and cost-effectiveness compared to traditional organic dyes.5An efficient lumiphores for LSC should meet these requirements: (a) broad light absorption (b) high photoluminescence quantum yield (PLQY), (c) large Stokes shift (absence or low overlap between absorption and emission spectra), (d)compatibility with the host matrix material and (e) low cost. By exploiting the excellent properties of QDs, such as the size-tunable absorption and emission, herein we will introduce different strategies to achieve cost-effective large-area (100cm2) LSC based on inorganic QDs.3, 6, 7 Furthermore, in order to reduce the environmental impact of such devices, it will be explored the use of carbon dots (Cdots) as organic nano-emitters for LSC. Cdots are the latest addition to the carbon nanoallotropes family and they are exclusively composed of non-toxic elements, such as nitrogen, carbon and oxygen. They can be easily synthetized in large quantities by solvothermal method. Their main advantages, compared to conventional semiconducting quantum dots (QDs), is the non-toxicity, environmental friendliness, low-cost and simple preparation using abundant carbon based feedstock.In this work different type of Cdots with different surfaces functionalization and optical features are prepared. In particular their absorption and emission spectra are tuned in the Visibile/Near infra-red range.Carefully chosen Cdots are then employed as luminophores for metal-free large-area LSC.8, 9

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