Im working on a piezoelectric materials which gives a very low output voltage which is of no use to me.I wanted it to be amplified using some circuit or an ic.
The usual keyword is "energy harvesting" rather than "amplifier", which caused much confusion
as you can see. I fear, that 20 mV is effectively too low, but you can check the various links in
previous threads at edaboard. To check, if you can ever expect a glim of light, you should start
with a hand calculation in terms of available power and energy.
My basic thought is, that piezo elements can be easily stacked up to increase the output voltage.