Improved efficiency and stability of the organic solar cells (OSCs) are the critical considerations for practical applications. The interface between the interlayer and bulk heterojunction has recently been shown as one of the weak links associated with the degradation in the nonfullerene acceptor (NFA)based OSCs. It shows that the removal of the interfacial chemical reactions between the 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (INCN) moieties in NFA and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) hole extraction layer (HEL) is desired for enhancing the device stability. In this work, we show that the use of a bilayer MoO 3 /antimonene HEL favors the operational stability in OSCs through maintaining a high builtin potential and suppression of an undesired interfacial reaction between INCN moieties in NFA and the PEDOT structures in PEDOT:PSS. A power conversion efficiency of 16.68% is also obtained for the OSCs with a bilayer MoO 3 /antimonene HEL, prepared using a blend system of PM6:Y6, demonstrating its suitability for high-performance OSCs.

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Ultrathin iridium (Ir) complexes (e.g., bis[2‐(4,6‐difluorophenyl)pyridinato‐C2,N](picolinato)iridium(III) (FIrpic)) are first introduced as electron extraction layers (EELs) in non‐fullerene organic photovoltaics (OPVs), and a set of devices based on non‐fullerene materials is fabricated. It is demonstrated that this approach can rationally enhance the corresponding short current density and open circuit voltage and finally improve the photovoltaic performance of OPVs. Furthermore, optimized bilayer EELs using combined FIrpic and 8‐hydroxyquinoline lithium (Liq) are investigated. The resulting device presents excellent power conversion efficiency (PCE) of 15.85%, which is much higher than that of control device without FIrpic layer (14.6%). Moreover, Ir complexes show great universality when combined with other materials serving as EELs. This may provide an extra direction for further enhancement of OPVs performance.

Ultraviolet (UV)‐durable organic solar cells (OSCs) are realized by incorporating a CdSe@ZnS quantum dots (QDs)‐modified PEDOT:PSS hole extraction layer (HEL). The use of the CdSe@ZnS QDs‐modified PEDOT:PSS HEL has an obvious improvement in UV‐durability of OSCs. A more than 50% reduction in the power conversion efficiency (PCE) is observed for a (PM6:Y6)‐based control OSC with a PEDOT:PSS HEL, under the 1000 min accelerated UV (365 nm, 16 W) aging test. Whereas a much reduced reduction of 35% in PCE is observed for the OSCs with a CdSe@ZnS QDs‐modified PEDOT:PSS HEL, under the same accelerated UV aging test condition. Results reveal that the Coulombic attraction between the PEDOT units and PSS chains in the PEDOT:PSS layer is disturbed due to the interaction between hydroxyl ligands of the CdSe@ZnS QDs and PSS through hydrogen bond, leading to an increase in the electric conductivity in PEDOT:PSS layer through transforming PEDOT quinoid structure to expanded‐coil structure. The use of the CdSe@ZnS QDs‐modified PEDOT:PSS HEL also favors the efficient operation of the nonfullerene acceptor (NFA)‐based OSCs through maintaining a high built‐in potential across the bulk heterojunction. The results demonstrate the importance of the interface engineering to alleviate UV light‐induced degradation processes of NFA‐based OSCs.