State-of-the-art n-i-p perovskite solar cells (PSCs) suffer from stability issues due to ionic interdiffusion. Herein, by enlarging indacenodithiophene -bridge donor (D’) to combine with methoxy triphenylamine donor (D) and benzothiadiazole...

Among the various conducting polymers, polyaniline (PANI) has received a great deal of attention due to its low cost, excellent chemical and thermal stabilities, and high electrical conductivity. Herein, a newly designed self‐doped water‐soluble PANI derivatives‐poly (diphenylamine‐4‐sulfonic acid) (PDAS) is readily prepared and applied as hole extract layer in nonfullerene organic solar cells. PDAS, with satisfactory structural and electrical homogeneity, exhibits high conductivity of 7.75 × 10−2 S cm−1, none of acidity (with pH around 7), as well as enhanced work function of 5.43 eV, compared with the well‐known poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The power conversion efficiency of PDAS‐based devices is comparable with that of PEDOT:PSS‐based devices with the PM6:BTP‐4F‐12 as active layer. The successful design of the new self‐doped water‐soluble conductive polymer and its commercial application potential is demonstrated.

Poly(3,4-ethylenedioxythiophene): poly(styrene-sulfonate) (PEDOT: PSS) has been the most popular conductive polymer as a hole transport material in organic solar cells (OSCs). Modification of PEDOT: PSS can improve its various properties to realize high performance in OSCs. The conductivity of PEDOT: PSS is an essential factor in determining device performance. In this work, PEDOT: PSS-BA, PEDOT: PSS-HA, and PEDOT: PSS-OA are prepared via facile doping of corresponding alkyl diamines into PEDOT: PSS, considering the amino ion can interact with redundant sulfonic acid groups of PSS. All the modified products exhibit enhanced conductivities due to their more ordered molecular packing comparing PEDOT: PSS. Using PTQ10 and m-BTP-PhC6 as the binary active layer, the OSC devices based on PEDOT: PSS-BA yield a superior power conversion efficiency of 18.44%, which ranks as one of the highest values in the binary OSCs.

2‐(3‐Oxo‐2,3‐dihydro‐1H‐inden‐1‐yli‐dene)malononitrile (IC) derivatives are popular and crucial acceptor building blocks for the construction of highly efficient n‐type organic semiconductors. However, it is still challenging to increase their relatively poor chemical stability and photostability, originating from their unstable vinyl protons. Herein, two stable acceptor–donor–acceptor narrow‐bandgap materials LY1 and LY2 via replacing the IC series end groups of typical nonfullerene acceptors with IC‐fused fluorenyls are reported. The enhanced conjugation and strong electron‐withdrawing capability enable LY1 and LY2 to show lower bandgap, a deeper lowest unoccupied molecular orbital energy level, enhanced electrochemical stability, and significantly improved photostability compared with IT‐4F and IT‐4Cl. Benefiting from the broadened absorption and promoted nonradiative transition, LY1 and LY2 display enhanced photothermal conversion performance, presenting as promising pure organic photothermal materials.

Non-fullerene acceptors exhibit great potential to improve photovoltaic performances of organic solar cells. However, it is important to further enhance chemical stability and device durability for future commercialization, especially for Y6-series small molecule acceptors with 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (IC) type as ending group. In this work, an IC-free photovoltaic material YF-CN consisting of 2-fluoren-9-ylidenepropanedinitrile terminal was designed and synthesized by stille coupling. YF-CN exhibits enhanced photostability and improves morphological compatibility with the binary PCE10:Y6 blend. The moderate energy level makes YF-CN could serve as a multifunctional material, such as donor, acceptor and the third component. When adding YF-CN as second donor into PCE10:Y6 system, an improved power conversion efficiency of 12.03% was achieved for as-cast device. Importantly, the ternary PCE10:YF-CN:Y6-devices showed enhanced storage durability maintaining 91% of initial PCE after the 360 hours. This work provides new perspective to understand the open-shell and closed-shell structure of donors and acceptors, as well as promising design concept of stable IC-free acceptors for organic solar cells.