Cooperative Charging in a Nanocrystal Assembly Gated By Ionic Liquid
  In order to make a densely packed assembly of undoped semiconductor nanocrystals conductive, it is usually gated by a room temperature ionic liquid. The ionic liquid enters the pores of the super-crystal assembly under the influence of an applied voltage. We study the capacitance of such a device as a function of the gate voltage. We show that, counter-intuitively, the capacitance of the system is the sum of delta-functions located at a sequence of critical gate voltages. At each critical voltage every nanocrystal acquires one additional electron. 
Tianran Chen, Brian Skinner, B. I. Shklovskii
cond-mat.mes-hall