Selective sulfur substitution of the distal carbonyls of a core-substituted naphthalene diimide was obtained when a combination of core and imide substituents were used. The substituents appear to inhibit thionation of the proximal carbonyl by steric hindrance. Each thionation caused a 50 nm bathochromic shift of the visible absorption band and an anodic shift of the reduction potentials. The dithionated compound has a l max in the near-IR at 733 nm and an optical gap of 1.59 eV, which is unusually low for this type of molecule. Thionation of carbonyls offers a useful avenue for tuning optoelectronic properties of NDIbased materials.

Strategic fluorination of non-planar electron acceptors reduces bimolecular recombination in OPVs and significantly enhances the electron mobility to ∼10−3 cm2 V−1 s−1 in diodes.

SummaryHomoleptic zinc(II) complexes of di(phenylacetylene)azadipyrromethene (e.g., Zn(WS3)2) are potential non-fullerene electron acceptors for organic photovoltaics. To tune their properties, fluorination of Zn(WS3)2 at various positions was investigated. Three fluorinated azadipyrromethene-based ligands were synthesized with fluorine at the para-position of the proximal and distal phenyl groups, and at the pyrrolic phenylacetylene moieties. Additionally, a CF3 moiety was added to the pyrrolic phenyl positions to study the effects of a stronger electron withdrawing unit at that position. The four ligands were chelated with zinc(II) and BF2 + and the optical and electrochemical properties were studied. Fluorination had little effect on the optical properties of both the zinc(II) and BF2 + complexes, with λmax in solution around 755 nm and 785 nm, and high molar absorptivities of 100 × 103 M−1cm−1 and 50 × 103 M−1cm−1, respectively. Fluorination of Zn(WS3)2 raised the oxidation potentials by 0.04 V to 0.10 V, and the reduction potentials by 0.01 V to 0.10 V, depending on the position and type of substitution. The largest change was observed for fluorine substitution at the proximal phenyl groups and CF3 substitution at the pyrrolic phenylacetylene moieties. The later complexes are expected to be stronger electron acceptors than Zn(WS3)2, and may enable charge transfer from other conjugated polymer donors that have lower energy levels than poly(3-hexylthiophene) (P3HT).

Unusually broad thin-film visible absorption (500–800 nm) for naphthalenediimide molecules was obtained by using the combination of alkylamino core substituents and styryl imide substituents.

Quantum Dot downconverters will enable high‐resolution, bright, and wide color gamut displays for all display formats. We have developed a method to directly photopattern densely packed InP/ZnS Quantum Dots that achieve an optical density of 2 at sub 10 µm thicknesses while preserving high photoluminescence quantum yield.

Quantum Dot downconverters can provide a scalable solution to tri‐color high‐resolution microLED and OLED displays by converting monochrome displays using photopatternable red and green QDs. Using internal measurements collected at NanoPattern Technologies, Inc. we model and discuss the practical wall plug efficiencies for downconverted InGaN blue microLED displays. In the range of 5 μm pixel sizes, using uncorrected 65 % film PLQY, the downconverted InGaN red emitter achieves a comparable external quantum efficiency compared to a direct red emitting AlInGaP when compared at practical current densities for microLED drivers.

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