Ultrathin Epitaxial Lift-off GaAs Solar Cell Array with Highly Flexible and Lightweight Characteristics

Abstract

Recent interests increasing in ultraflexible and ultralight solar cells with reliable and high efficiency for untethered power supply to electronic devices such as attachable, implantable, and miniaturized drones, etc. However, the structural limitation of material obstructs the coexistence between the ultraflexible characteristics and the high electrical performance. This dissertation proposes an ultrathin, ultralight solar cell array with high efficiency on an ultrathin polymer film. Framing of 1.4 μm thick ultrathin film and a series of processes of cold-welding, epitaxial lift-off (ELO), and microfabrication gives the GaAs solar cell array ultraflexible and ultralight characteristics. The mechanical characteristics of the ultrathin GaAs photovoltaic (PV) array were analyzed through finite element analysis and planar compression test. The PV array operates under extreme deformation and demonstrates the connectivity to diverse unconventional surfaces. Lastly, the ultralight characteristic was ensured with a specific power of 5.44 W/g.