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Dye‐sensitized solar cells (DSCs) based on copper(II/I) redox mediators have recently achieved notable performance progress through tailoring the ligand structure of the copper complexes, exploiting cosensitization, and introducing an advanced device structure. In order to further improve the power conversion efficiency (PCE), it is imperative to develop wide spectral‐response photosensitizers compatible with the copper(II/I) redox mediators while attaining a high Voc. Herein, a blue photosensitizer coded R7 is reported, which is purposely designed for highly efficient DSCs with copper‐based electrolytes. R7 features a strong electron‐donating segment of 9,19‐dihydrobenzo[1′,10′ ]phenanthro[3′,4′:4,5]thieno[3,2‐b]benzo[1,10]phenanthro[3,4‐d]thiophene conjugated with a bulky auxiliary donor N‐(2,4′‐bis(hexyloxy)‐[1,1′‐biphenyl]‐4‐yl)‐2,4′‐bis(hexyloxy)‐N‐methyl‐[1,1′‐biphenyl]‐4‐amine and the electron acceptor 4‐(7‐ethynylbenzo[c][1,2,5]thiadiazol‐4‐yl)benzoic acid. The blue dye R7 with bulkier auxiliary donor moiety in the DSC largely outperforms the reference dye R6, which has a smaller bis(4‐(hexyloxy)phenyl)amine donor unit. Transient absorption spectroscopy and electrochemical impedance spectroscopy measurements show that the R7 based DSC has a higher charge separation yield, a higher charge collection efficiency, and lower charge recombination with the copper electrolyte than the R6 based counterpart. A cosensitized system of R7 and Y123 for the DSC presents an outstanding PCE of 12.7% and retains 90% of its initial value after 1000 h of light soaking under 1 sun at 45 °C. [ABSTRACT FROM AUTHOR]

Four ZnPc‐dimers with 2,5‐thienyl (ZnPc−th−ZnPc 1), 2,7‐fluorenyl (ZnPc−flu−ZnPc 2), 3,6‐bisthienylldiketopyrrolopyrrole (ZnPc−DPP−ZnPc 3) and 1,4‐phenyl (ZnPc−p−ZnPc 4) bridges have been studied as dopant‐free hole transporting materials (HTMs) in perovskite solar cells (PSCs). The synthesis and characterization of ZnPc−th−ZnPc 1 and ZnPc−flu−ZnPc 2 dimers are reported for the first time. Steady state and time resolved photoluminescence demonstrate the good hole‐extraction capability of these materials. The best efficiencies obtained for dimers 1, 2, 3 and 4 are 15.5 %, 15.6 %, 16.8 % and 15.7 %, respectively, without the addition of dopants. Besides, these derivatives demonstrated better stability both in dark storage conditions with a relative humidity <20 % for 500 h and at 50 °C with a relative humidity >60 % for 160 h when compared to doped spiro−OMeTAD. The push‐pull nature of dimer ZnPc−DPP−ZnPc 3 has led to the highest efficiency among the ZnPc derivatives under study demonstrating that donor‐acceptor‐donor systems can be good alternatives to commonly used materials due their energy levels, low cost and the final morphology of the hole transporting layer. [ABSTRACT FROM AUTHOR]