Redox-Enabled Microscale Opto-Electronically Transduced Electrodes (ReMOTEs)

We present the elements of a pH-measuring autonomous microsystem, a Redox-Enabled Microscale Opto-Electronically Transduced Electrode (ReMOTE). The ReMOTE contains two electrodes of different materials, where the nearby
$\mathbf{pH}$
dictates the voltage between the two electrodes. The ReMOTE is a tetherless, all-optical microsystem which is powered and is transmitting its data optically. The ReMOTE is designed in a 180 nm CMOS SOI process, occupies merely
$\mathbf{417}\ \mu \mathbf{m}\times \mathbf{48}\ \mu \mathbf{m}$
, and it only consumes
$\mathbf{2}\ \mu\mathbf{W}$
. For the functional verification, we have conducted pH measurements using a thin film titanium nitride working electrode and a Ag/AgCl reference electrode, of which the voltage per pH sensitivity was 42.53 mV/pH.