Amine-Functionalized Carbon Dots as PEDOT:PSS Dopants for Organic Solar Cells

The hole transport layer (HTL) is an important component in organic solar cells (OSCs). As a commonly used HTL, poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) in OSCs generally exhibits relatively low conductivity, hindering device performance improvement. Herein, amine-functionalized carbon dots (CDs-N) are introduced as dopants of PEDOT:PSS, which can effectively enhance the HTL conductivity while maintaining a similar work function. The PEDOT:PSS+CDs-N devices exhibit higher power conversion efficiencies due to the improved charge extraction ability. It is found that the larger conjugated backbones of CDs-N and the amine functional groups interacting with PSS are keys for such optimization. This work illustrates the potential of CDs for the applications on interface layers in OSCs.