“…LbL assembly is particularly well suited for formation of interfacial dipole layers, as it enables the assembly of polyelectrolyte multilayers at a nanometer-scale precision regardless of electrode structures without altering the bulk properties of photoelectrodes. [37,38] Thus, the bulk properties of photoelectrodes, such as bandgap and conductivity, remain intact while their interfacial properties could be engineered. In this study, PDDA and PSS were selected as the cationic and anionic polyelectrolytes for modifying photoanodes, owing to the following characteristics: i) high electrochemical stability (Figure S1, Supporting Information), ii) distinct charge density independent of external pH as strong electrolytes, and thereby, and iii) formation of stable polyelectrolyte multilayers on various photoanodes, which have different stability and/or operating pH windows.…”