I have tested an organic photovoltaic (OPV) panel from Dracula Technologies and it performs as specified. It is light and flexible. Indoors in low light it performs better than a crystalline solar panel. I believe OPV is the best technology for indoor light harvesting. LAYER® modules are currently produced in pre-series and will be available at industrial scale in 2022.
LAYER® is a technology by Dracula Technologies to print organic photovoltaic modules using its specific ink formulation based on environmentally friendly solvents and using industrial scale printheads. They print to sheets and not to rolls like competitors and that enables making specific shapes for example logos.
The layers are encapsulated using flexible barrier films to avoid direct contact with the printed layers and mainly to limit the diffusion of oxygen and moisture.
OPV cells are light weight, flexible, and have low environmental impact. They are potentially easily recyclable, and cheap to produce since it is a digital printed technology. OPV cells absorb in the visible light spectrum 400-700nm. Crystalline silicon (c-Si) absorbs more of the solar spectrum making them ideal for outdoor. Amorphous silicon is more balanced but less efficient than c-Si in outdoor luminosity and less efficient than OPV for indoor light. So, for indoor light sources OPV is the best. OPV materials are tunable to absorb specific light spectra: for indoor, outdoor or mixed environment. Dracula Technologies has tuned the absorption spectrum to indoors where LED and fluorescent light sources are dominant.
Dracula Technologies have tested their OPV over 1000 hrs using a 1 SUN simulator where the temperature reached 40-50 degrees Celsius and the power output showed great stability.
These are the specifications of the LAYER #6 DemoKit.
The operating temperature is limited to 0 to 40 degrees Celsius making this suitable only for indoor locations.
Testing the electrical specifications
I used an overhead LED panel, a lux meter and a multimeter to measure open circuit voltage and short circuit current and moved the OPV panel in and out the light to adjust the illuminance.
Voc - measured open circuit voltage (V)
Isc – measured short circuit current (V)
It performs as specified!
Comparing charge current with a crystallin silicon panel