Triplet-excited-state energies of perylene-monoimides (PMIs) lie in the range 1.12 eV ± 2 meV when compared to singlet-excited-state energies of about 2.39 eV ± 2 meV; therefore, the corresponding naphthalene-linked PMI-Dimer was investigated as a novel singlet-fission (SF) material. Ultrafast transient absorption measurements demonstrated the (S 1 S 0 )-to-1 (T 1 T 1 ) transformation and the involvement of a mediating step in the overall 1 (T 1 T 1 ) formation. The intermediate is a charge-transfer state that links the initial (S 1 S 0 ) with the final 1 (T 1 T 1 ), and imposes charge-transfer character on both, which are thus denoted (S 1 S 0 ) CT and 1 (T 1 T 1 ) CT . At room temperature, the decorrelation and stability of 1 (T 1 T 1 ) CT is affected by the geminate triplet−triplet recombination (G-TTR) of the two triplets. Independent confirmation for G-TTR to afford upconverted (S 1 S 0 ) UC in fsTA and nsTA measurements with PMI-Dimer, came from probing PMI-Monomer (T 1 )s in triplet−triplet annihilation up-conversion (TTA-UC). The G-TTR channel, active in the PMI-Dimer at room temperature, is suppressed by working at either low temperatures (∼140 K) or in polar solvents (benzonitrile): Both scenarios assist in stabilizing (T 1 T 1 ) CT . As a consequence, the triplet quantum yields are 4.2% and 14.9% at room temperature and 140 K, respectively, in 2-methyltetrahydrofuran.

The unique singlet-fission (SF) properties of a previously studied naphthalene-linked perylene monoimide (PMI-N-PMI) motivated the synthesis of a phenylene spaced perylene monoimide (PMI-P-PMI) and their corresponding phenylene- and napthylene-spaced perylene-diimides...

A mild, fluoride-mediated reaction for the direct introduction of amines and N-heterocycles.

The charge selective layer is of significance for the fabrication of emerging photovoltaics, including perovskite-based solar cells. Molecular hole transport materials (HTMs) are being employed as charge transporters, owing to their synthetic molecular flexibility that allows the fine-tuning of their electro-optical properties. Typically, doping of HTMs is essential, but it is a trade-off between long-term durability and device performance. The energetic level of perylenediimides (PDIs) was altered by the position of the substituent. The substituent’s position influences the geometry of the PDI core, which can lose planarity, thus presenting a core twist angle between the two naphthalene subunits to find its application as hole-selective layers for fabrication. We have fabricated perovskite solar cells, with pristine PDI, and it gave a competitive performance. New design protocols for PDIs are required for aligned energetic levels, which will minimize recombination losses in solar cells, favoring a performance enhancement. Graphical abstract

A mild fluoride-mediated reaction for the synthesis of 1,6,7-triaminoperylenediimides.