Photocurrent-voltage (I-V) characteristics were recorded using a
Keithley 2400 source meter under simulated AM 1.5G light illumination
(100 mW cm2) generated from an Oriel 150 W Xe lamp.
The external quantum efficiency (EQE) spectra were measured
using an Acton monochromator connected to a 250 W tungsten
halogen lamp. The solar cells were masked with a metal aperture to
define the active area to be 3 mm 3 mm.