Carbon Nanotube IR Photothermovoltaic Devices: Power, Fill Factor, and Transient Response

The power output, fill factor (FF), and transient photoconduction characteristics of infrared photothermovoltaic devices comprising mainly semiconducting single-walled carbon nanotubes are studied as a function of incident optical power and temperature. Explicit analytical expressions for the electrical power and FF are derived and verified experimentally. An improvement in the figure of merit is found to counterbalance the effect of FF reduction on the output power under high illumination fluxes. The transient response is shown to be limited by the RC parameter and not by nanotube-associated heat transport processes.