Enhanced spectral coverage in tandem organic solar cells

Abstract

In order to realize enhanced spectral coverage in organic photovoltaic devices, the authors have stacked a zinc phthalocyanine: C 60 based cell on the top of a poly-3-hexyl-thiophene:[6,6]-phenyl C 61 -butyric acid methyl ester layer using a 1 nm thick Au intermediate recombination layer. Such tandem devices comprising active materials with complementary absorption spectra exhibit a short circuit current ( I sc ) of 4.8 mA cm − 2 , an open circuit voltage ( V oc ) of 1020 mV , and a fill factor of 0.45. Measurements of the photocurrent versus wavelength of the incident light show that photons are converted into charge carriers from 400 to more than 800 nm . Further optimization of the respective layer thicknesses may lead to high efficiency devices.