A MEMS Photosynthetic Electrochemical Cell Powered by Subcellular Plant Photosystems

A microelectromechanical systems (MEMS) photosynthetic electrochemical cell
$(mu PEC)$
was demonstrated that harnesses the subcellular thylakoid photosystems isolated from spinach cells to convert light energy into electricity. Subject to light intensity of 2000
$mu mol$
photons/
$ m ^2$
/s, it generated an open circuit voltage (OCV) of 470 mV and a current density of 1.1
$mu A/cm^2$
at 5.2
$mu V$
. In the dark, the
$mu PEC$
continued to yield power for a few minutes using reduced equivalents generated during illumination, generating 330 mV OCV and 0.1
$mu A/cm^2$
with a 1
$ kOmega$
load. The output level is comparable to other MEMS biological fuel cells previously reported. The biosolar cell was bulk-micromachined from silicon and Pyrex substrates and assembled like a fuel cell in an anode-PEM-cathode configuration. This biosolar cell could have potential to serve as a power source for micro-scale devices like remote sensors.1359