LumEN: Luminescent Solar Concentrators for Sustainable, On-Demand Electricity Production

Gianmarco Griffini, Massimo Micocci, and Francesca Ostuzzi,
Politecnico di Milano,
Milan, Italy

Lum-EN is the first portable device able to harvest solar energy and deliver electrical energy on-demand, employing organic luminescent solar concentrators (OLSCs). High light-to-electricity efficiencies can be attained with little use of conventional solar cells.

Typical OLSCs consist of a luminescent organic dye dissolved into an inexpensive transparent matrix material such as poly(methylmethacrylate). The luminescent species absorb the incident solar light and isotropically re-emit it at a longer wavelength. A large part of the emitted photons is trapped in the OLSC plate by total internal reflection and wave-guided towards the edges, where solar cells are placed. Ideally, the emission spectrum of the luminescent species matches with the absorption spectrum of the solar cell so that its power conversion efficiency can be improved and a reduction of the actual active surface area of the solar cell can be attained, thereby ensuring reduction of costs of solar energy production.

As opposed to simple solar cells that can only work under direct sunlight, the OLSC panels can operate well under diffuse light, making it possible for Lum-EN to be used in poorly illuminated environments, cloudy locations, or even indoors. By varying the active surface of the luminescent solar concentrators, the output energy can be modulated so as to power a set of LEDs or recharge a smartphone, tablet, or any portable device.

Lum-EN can be used in all situations where a standalone energetic source is needed, such as during outdoor activities, excursions, camping, or sailing. The device is easily transportable (lightweight and pocket-sized) and easy to use.

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Honorable Mentions

Catherina, Smartly Illuminate Your Life

Valentin Kulikov,
Slovak Republic

Catherina presents autono mous indoor lighting that utilizes recent advances in LED technology. This luminaire is designed to be used as a compact light source with high efficiency and long lifetime. With the implementation of a highly sensitive PIR detector, Catherina behaves autonomously. It allows the user to get illumination when needed without touching any switch. The user can precisely select the threshold value for minimal ambient light. If the ambient light is below this threshold level (getting dark) and movement is detected, light is continuously increased and switched on. After approximately 45 seconds, when there is no movement, it is slowly faded out and finally switched off. For more information, visit 

Ultra-Efficient Lighting

Alistair Macfarlane,
East Kilbride, Scotland

In these ultra-high-efficiency LED light bulbs and luminaires, each of the individual LEDs produces little local heat and is individually cooled by PCB track and/or small SMT tinned copper fins, which, with airflow through the bulb, provides exceptional cooling without large-finned heat sinks or the need for isolation. The LEDs can be directed to give light in near-spherical distribution or made directional. A user-adjustable sensor mounted in each bulb allows automatic dimming to be selected, saving energy on days when the Sun shines, but the lights remain on. An option is remote-controlled dimming from a tiny remote that has both a flashing LED so it can be located in the dark, and is self-charging from a photocell so that batteries never need to be replaced.

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