Effect of thermal annealing on a ternary organic solar cell incorporating Gaq3 organometallic as a boosting acceptor

Abstract

In this work, the impacts of thermal treatment on the optical, structural and photovoltaic properties of ternary organic solar cells based on DH6T:Gaq3:PC61BM are investigated in the temperature range from 413 to 493 K. The addition of Gaq3 organometallic material as a secondary acceptor is to boost the performance and reproducibility of the devices. The results showed an increased crystallinity, improved photo-absorption and decreased photoluminescence response for the active layers upon annealing to up to 453 K, which was accompanied by the enhancement in the overall photovoltaic performance of the devices by about 11%. A non-monotonic change in the open circuit voltage (Voc), short circuit current (Isc) and fill factor (FF) was noticed due to temperature changes. A reasonable batch-to-batch reproducibility was achieved, accentuating a stable operation of the devices under thermal variations.