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2023
Presentation
Title
Over 1600 V DC voltage from highly efficient solar mini modules
Title Supplement
Presentation held at Materials for Sustainable Development Conference, MATSUS 2023, Torremolinos, Spain, 16.10.2023-20.10.2023
Abstract
Low power high voltage sources can be used to drive many interesting devices, for example, dielectric elastomer actuators (DEAs), electroaerodynamic propulsion (EAD thruster), micro-electromechanical systems (MEMS), among others. These devices show great potential for smart life applications in the future. However, one common bottleneck is power supply, which usually comes from cables or converters via a battery. The cables limit working space, while batteries restrict working time. To overcome these drawbacks, some groups developed triboelectric nanogenerators to drive DEAs. However, this type of energy supply is based on motion and the performance relies on vibration frequency which is confined for real applications. Developing a solid state, high efficiency and environmentally compatible high voltage source is therefore timely. Harvesting light energy from environment by photovoltaics (solar cells) is a common way to realize energy autonomy. One single junction solar cell usually can generate a voltage of 0.5-1.5 V, depending on the active material and the illumination intensity. To achieve high voltage output, interconnecting single solar cells in series to a module is an efficient way. A lot has been done to meet the need of MEMS in the range from dozens to hundreds of Volts. But this is not high enough for DEAs and EAD thrusters that usually need thousands of Volts. To the best of our knowledge, no mini solar module with an open circuit voltage (VOC) higher than 1000 V has been reported thus far. Here we report a mini organic solar module with 1640 individual solar cells interconnected in series on 3.6 × 3.7 cm2 realized by laser patterning. We used two different active materials, namely PV-X plus and PM6:GS-ISO. Under 100 k lux warm white LED illumination, the PV-X plus gives a VOC of 1362 V, with a short circuit current (ISC) of 97.2 µA, fill factor (FF) of 0.67 and a maximum power (Pmax) of 89.3 mW, while the PM6:GS-ISO gives a VOC of 1640 V, ISC of 25.2 µA, FF of 0.59 and Pmax of 24.4 mW. Noteworthy, the PV-X plus device can still provide a VOC of 1141 V under an illuminance as low as 1000 lux. This means that the solar modules can work excellently under normal indoor environment even without any additional illumination sources. As a power source, stability is also important for real applications. We kept the devices near the VOC point to test the stability of the organic solar modules under 100 k lux illumination. The performance of PV-X plus shows almost no degradation at all within 30 min, while the PM6:GS-ISO degrades slightly, but still keeps 89.6% of the initial value. To proof the usefulness of the high voltage modules, we combined several modules to get a higher voltage output and could this way successfully drive different types of DEAs. In addition, we also powered a DEA thruster. In a hanging mode, the DEA thruster moved about 20 mm in 0.5 s. The thrust force is measured as 136 µN. Future work on the solar modules will include the use of flexible substrates and enhancing VOC values by further minimizing the individual cell size and thus the number of series interconnected cells hence providing more potential for integration with DEAs and EAD thrusters.
Author(s)
Rights
Under Copyright
Language
English