Recent advancements at the intersection of organic photovoltaics and soft robotics have led to the development of high-voltage organic photovoltaic mini-modules (HV-OPMs), which can achieve open-circuit voltages exceeding 5000V. This breakthrough is set to expand the capabilities of dielectric elastomer actuators (DE) and other low-power high-voltage devices, enabling them to operate autonomously without the constraints imposed by batteries and traditional power grids.
Historically, high-voltage devices, including DEs and electroaerodynamic thrusters, have relied heavily on bulky battery packs and voltage amplifiers, which limit mobility and operational time. With increasing demand for portable high-voltage solutions for soft robotics and micro aerial vehicles, researchers have worked to overcome these limitations by innovatively integrating photovoltaic technology.
The new HV-OPMs, which occupy just 3.8x3.9 cm2, consist of 5024 individual sub-cells. These special designs were created with the efficient organic material PM6:GS-ISO and achieved impressive results. Under illumination conditions of 100 klux from white LED lights, these mini-modules generated open-circuit voltages of 5534V, with corresponding conversion efficiency of 6.4%. An alternative configuration using PV-X plus yielded 3970V with increased efficiency of 19.0%.
Researchers utilized laser structuring for the fabrication process, which offers advantages over traditional methods like photolithography; this includes faster production times and the ability to create flexible devices. The direct laser patterning provides higher geometric fill factor (GFF) ratios and minimized geometric loss, producing high-efficiency outputs without compromising electrical performance.
Electroluminescence imaging and dark lock-in thermography were also employed to analyze performance, allowing for detailed examination of voltage losses and overall reliability. Importantly, the absence of significant potential-induced degradation during assessments marks these HV-OPMs as reliable for continuous duty.
To demonstrate practical applications, researchers also showcased the ability of these modules to power DE suction cups. When connected to one of the HV-OPMs, these actuators managed to produce sufficient suction to lift objects weighing up to 28 grams under illumination. This showcases the potential of HV-OPMs to revolutionize how soft robotic systems are powered, potentially eliminating the need for external power supplies or batteries.
Both the PM6:GS-ISO and PV-X plus based modules have garnered attention for their high voltage outputs and efficiencies, setting new records for organic photovoltaics. Such capabilities promise to facilitate energy harvesting from environmental light sources, contributing to energy autonomy for numerous applications.
Conclusively, the HV-OPMs present remarkable potential for enhancing the energy autonomy of advanced robotic systems, providing pathways for future research to optimize power management systems and structural designs, paving the way for broader applications beyond soft robotics.
Future implementations will need to address challenges such as integrating control circuits and processing on flexible substrates for dynamic applications. Nevertheless, the innovation marks significant progress toward self-sustaining energy sources for high-voltage devices.