Highly Efficient Microscale Gallium Arsenide Solar Cell Arrays as Optogenetic Power Options

Abstract

Optogenetics is one of the most powerful investigation tools in neuroscience research. A major engineering challenge is the wireless power supply needed to operate the light-emitting diodes (LEDs) and generate over 1 mW/mm2 optical power density required to activate opsins. Here, we describe design strategies to construct gallium arsenide microscale solar cells and approaches to integrate them into array structures as efficient optogenetic power options. The photovoltaic (PV) system outputs an electric power of 2.30 mW with an open-circuit voltage $(V_{{\rm{oc}}})$ of 4.97 V and a short-circuit current $(I_{{\rm{sc}}})$ of 0.59 mA under direct infrared illumination. We show that this power level is enough to operate both blue and yellow LEDs and provide optical power densities of 3.5 and 2.3 mW/mm2, respectively. This paper provides a guideline to design efficient PV systems as power supplies for optogenetics and other biomedical implants.