Self‐Assembled Monolayer Post‐Treatment of Surface Phase‐Flipped Polyelectrolyte for Efficient Selective Charge Transport in Organic Photodiodes

ABSTRACT This study highlights the efficient and selective charge transport ability of the transfer‐laminated poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) interlayer after post‐treatment with self‐assembled monolayers (SAMs). To reduce the insulating PSS component, transfer‐lamination is employed, lowering the PSS content by inverting the surface morphology of PEDOT:PSS. Further, [2‐(3,6‐Dibromo‐9H‐carbazol‐9‐yl)ethyl]phosphonic acid (Br‐2PACz) is introduced as a SAM to treat the PEDOT:PSS surface, eliminating the residual PSS component and serving as a bridge between the anode and the active layer. This strategy can enhance selective charge transport capabilities, such as photo‐generated charge transport and externally injected charge blocking. The use of transfer‐laminated PEDOT:PSS with SAM post‐treatment enhances device performance in both organic photovoltaics (OPVs) and organic photodetectors (OPDs).