We report the preparation and X-ray crystallographic characterization of the first crystalline homoatomic polymer chain, which is part of a semiconducting pyrroloperylene-iodine complex. The crystal structure contains infinite polyiodide I∞ (δ-) . Interestingly, the structure of iodine within the insoluble, blue starch-iodine complex has long remained elusive, but has been speculated as having infinite chains of iodine. Close similarities in the low-wavenumber Raman spectra of the title compound and starch-iodine point to such infinite polyiodide chains in the latter as well.

Polymer zwitterions were synthesized by nucleophilic ring-opening of 3,3'-(but-2-ene-1,4-diyl)bis(1,2-oxathiolane 2,2-dioxide) (a bis-sultone) with functional perylene diimide (PDI) or fullerene monomers. Integration of these polymers into solar cell devices as cathode interlayers boosted efficiencies of fullerene-based organic photovoltaics (OPVs) from 2.75 % to 10.74 %, and of non-fullerene-based OPVs from 4.25 % to 10.10 %, demonstrating the versatility of these interlayer materials in OPVs. The fullerene-containing polymer zwitterion (C -PZ) showed a higher interfacial dipole (Δ) value and electron mobility than its PDI counterpart (PDI-PZ), affording solar cells with high efficiency. The power of PDI-PZ and C -PZ to improve electron injection and extraction processes when positioned between metal electrodes and organic semiconductors highlights their promise to overcome energy barriers at the hard-soft materials interface of organic electronics.

A new and highly efficient cathode interlayer material for organic photovoltaics (OPVs) was produced by integrating C60 fullerene monomers into ionene polymers. The power of these novel “C60‐ionenes” for interface modification enables the use of numerous high work‐function metals (e.g., silver, copper, and gold) as the cathode in efficient OPV devices. C60‐ionene boosted power conversion efficiencies (PCEs) of solar cells, fabricated with silver cathodes, from 2.79 % to 10.51 % for devices with a fullerene acceptor in the active layer, and from 3.89 % to 11.04 % for devices with a non‐fullerene acceptor in the active layer, demonstrating the versatility of this interfacial layer. The introduction of fullerene moieties dramatically improved the conductivity of ionene polymers, affording devices with high efficiency by reducing charge accumulation at the cathode/active layer interface. The power of C60‐ionene to improve electron injection and extraction between metal electrodes and organic semiconductors highlights its promise to overcome energy barriers at the hard‐soft materials interface to the benefit of organic electronics.

A series of perylene diimide (PDI)-containing ionene and zwitterionic polymers were prepared by the Menschuktin reaction and by nucleophilic ring-opening of a novel bis-sultone monomer. PDI derivatives containing tertiary amine moieties at the imide position, and bromides or phenyl groups within the aromatic core, provided sites for polymerization and imparted solubility during the polymerization, respectively. The solution photophysical behavior of the polymers was studied by UV–vis and photoluminescence spectroscopy as a function of PDI incorporation and cationic/zwitterionic functionality, resulting in the observation of tunable solution spectral features induced by core functionality and/or interzwitterion interactions. This new PDI-based polymer platform affords opportunities to modulate conjugation and charge density within the polymers and examine the effects of cationic vs zwitterionic groups on the resultant optoelectronic properties.

This paper describes a correlation between charge extraction and energy-level alignment at the interface of polymeric hole transport layers and perovskite active layers. By tailoring the composition of the conjugated backbone of the hole transport material, energy levels between perovskites and hole transport layers are varied. Matching the band alignment at perovskite/hole transport interfaces dramatically improved charge extraction and thus device performance. Time-resolved microwave conductivity measurements, performed to elucidate hole transfer kinetics, suggest that hole transport layer energy levels greatly influence hole extraction efficiency at this interface, a finding that agrees well with device performance metrics. Furthermore, photoluminescence, Mott–Schottky, and space charge limited current measurements support that energy-level alignment between the hole transport layer and perovskite active layer enables more efficient hole extraction and transport at the device interface. The insight surrounding hole extraction in inverted perovskite devices will help design effective hole transport materials, which, in turn, facilitates the production of more efficient solar cells.