Recent Progress of Inverted Perovskite Solar Cells with a Modified PEDOT:PSS Hole Transport Layer

Organic-inorganic hybrid perovskite solar cells (PSCs) has achieved the power conversion efficiency (PCE) of 25.2% in the last 10 years, and the PCE of inverted PSCs has reached >22%. The rapid enhancement has partly benefited from the employment of suitable hole transport layers. Especially, poly(3,4-ethenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is one of the most widely used polymer hole transport materials in inverted PSCs, because of its high optical transparency in the visible region and low-temperature processing condition. However, the PCE and stability of PSCs based on pristine PEDOT:PSS are far from satisfactory, which are ascribed to low fitness between PEDOT:PSS and perovskite materials, in terms of work function, conductivity, film growth, and hydrophobicity. This paper summaries recent progress regarding to modifying/remedy the drawbacks of PEDOT:PSS to improve the PCE and stability. The systematically understanding of the mechanism of modified PEDOT:PSS and various characteristic methods are summarized here. This Review has the potential to guide the development of PSCs based on commercial PEDOT:PSS.