SBIR-STTR Award

The promise of ubiquitous solar power for novel devices and applications depends greatly on the form-factors available, their specific power and their cost. Traditional silicon solar panels are prohibitively large for widespread utilization, and even smaller scale inorganic cells are too rigid and too heavy to be integrated into all next generation aero-structures, particularly medium-endurance and long-endurance unmanned aerial vehicles (UAVs). The promise of organic photovoltaics and organic electronics are the low mass and inherent flexibility enabled by such devices, and the potential for sizable cost reductions due to scalability. However, organic electronics suffer from rapid degradation when exposed to the elements, particularly oxygen and water vapor. In this program Vanguard will demonstrate the applicability of atomic layer deposition ultra-barrier coatings for encapsulating organic photovoltaic arrays. The approach will render suitable device lifetimes and will enable integration into UAV wing-skins using low-temperature co-curing techniques.

Benefit:
The benefits of the proposed flexible encapsulation scheme are the enabling of co-cured organic solar arrays around curved shapes, particularly those found on UAV wing-skins and bodies. However, the encapsulation system will also be of relevance to a wide variety of flexible organic electronics, including flat-panel displays. UAV systems including Vulture and Raven, as well as those currently under development, will be the intended transition targets for the proposed technology.

The promise of lightweight, flexible and ubiquitous solar power depends greatly on the form factors available, their ruggedness and their cost. Nascent technologies based on organic active materials require substantial isolation from moisture vapor and oxygen to enable peak performance and lifetime. All the while, the incorporation of such devices into aero-platforms like UAVs and high altitude airships further drives requirements for low-mass and surface smoothness to reduce drag. In this project, we will optimize the ultra-barrier coating system identified in Phase I to minimize its mass, to optimize and quantify is barrier characteristics, to demonstrate ruggedness and durability consistent with the needs of the application, and ultimately to integrate it into sub-scale and full-size wingskin hardware for demonstration purposes.

Benefit:
The promise of co-cured solar wingskins is the enhancement of flight-time endurance enabled by the embedded solar array, which is capable of re-charging onboard batteries during flight. For UAV platforms that require re-fueling at regular intervals, the incorporation of solar cells into the wingskin can allow a unit to remain in its flight path for substantially longer than baseline, potentially limiting the number of planes coming and going into a specific area. The output of this Phase II effort is an ultra-barrier encapsulation and co-curing technology that enables very lightweight photovoltaic arrays to be incorporated into UAV wingskins. The encapsulation technology meets the mass needs of solar-enhanced UAVs, and meets the ultra-barrier needs of organic electronics.

Keywords:
Wingskin, UAV, co-cure, photovoltaic, flexible, organic, barrier