Improving CdSeTe Devices With a Back Buffer Layer of CuxAlOy

The open-circuit voltage (V-oc) of CdTe-based photovoltaics may be limited by carrier recombination at interfaces (front or back) or in the absorber layer. Reduction in recombination of a given dominant mechanisms can lead to improved device performance if the remaining mechanisms turn ON in a narrow bias range just below the open circuit voltage. In this article, we demonstrate enhanced performance by incorporating solution-processed CuxAlOy to form a back-buffer layer in CdSe/CdTe devices. Outstanding minority carrier lifetimes of 656 and 4.2 ns were measured with glass side and film side illumination for device stacks processed with CuxAlOy. Devices demonstrated efficiencies of up to 17.4% with V-oc of 859 mV, FF of 75.6% and J(sc) of 26.9 mAcm(-2) while the efficiency of the reference device without the back-buffer layer was 16.5% with V-oc of 839 mV, FF of 70.6%, and J(sc) of 27.9 mAcm(-2).

Automated summary

The study demonstrates enhanced performance in CdTe devices by incorporating solution-processed CuxAlOy to form a back-buffer layer, resulting in increased efficiency and improved current characteristics. Reduction in carrier recombination can lead to improved performance in photovoltaic devices.