Annealing effects of Au nanoparticles embedded PEDOT:PSS in bulk heterojunction organic solar cells

The annealing effects of Au nanoparticles embedded PEDOT:PSS as the hole transport layer (HTL) of organic solar cells (OSCs) were studied. The annealing temperature affected the surface morphology and electrical properties of the devices. The root-mean-square value of the un-annealed HTL was about 5.05 nm, and decreased to 2.14 nm after annealing at 150 °C, indicating improved surface roughness. Three step variations in the weight loss were observed, the annealing temperature increased. The highest Raman peaks were found at 1437 cm−1 wave number. A red shift of the Raman peak was observed, as the annealing temperature increased. With annealing temperatures increase from 110 to 150 °C, the open circuit voltage and short circuit current density of the OSCs decreased from 0.596 V and 8.1 mA/cm2 to 0.586 V and 7.3 mA/cm2, respectively. The highest power conversion efficiency of 2.8% was obtained for the HTL annealed at 110 °C.