flying capacitor DC-DC converters are very inefficient for anything but small currents I believe - what current
is the load requiring?
A standard boost converter would prob. be a better answer apart from the bootstrapping issue - with only
1V at the source how to power up (most boost converters need more than that to operate).
You also have to worry about brown-outs when there isn't enough light to power the converter - will
it behave gracefully?
And when you say 1V to me that says 2 PV cells in series (they give about 0.5V under load) - is that the case?