Synergetic effects of acid treatment and localized surface plasmon resonance in PEDOT:PSS layers by doping HAuCl4 for efficient polymer solar cells

Abstract In this report, chloroauric acid (HAuCl 4 ) is used to modify PEDOT:PSS by doping in the aqueous solution, and the effects of HAuCl 4 concentration and annealing temperature on the characteristic of PEDOT:PSS have been investigated by a series of testing methods. The results show that HAuCl 4 can induce phase segregation between conductive PEDOT and insulated PSS − , which thus leads to the conformation change of the conductive PEDOT chains. Moreover, Au nanoparticles (NPs) can be formed upon mixing with PEDOT:PSS aqueous solution and the distribution of the Au NPs sizes become narrower with post-annealing. Thus, the conductivity of PDOT:PSS can be greatly improved by HAuCl 4 doping and post-annealing. Moreover, extinction and PL spectra indicate formed Au NPs in doping PEDOT:PSS layer also cause the effect of localized surface plasmon resonance (LSPR), which can enhance the light absorption in the polymer solar cells (PSCs). A champion PSC based on HAuCl 4 doping PEDOT:PSS has been obtained with power conversion efficiency (PCE) of 4.01 ± 0.13%, which shows up to 54.2% enhancement of the PCE comparing with that of the reference device without HAuCl 4 doping (2.60 ± 0.05%). The improvement can also be seen at PTB7:ICBA BHJ system with a high PCE of 8.05%, comparing with the reference device without HAuCl 4 doping (5.88 ± 0.05%). Thus the results here indicate that synergetic effects of acid treatment and LSPR in HAuCl 4 doping PEDOT:PSS layers are efficient for PSCs.