Energy-level modulation of coumarin-based molecular donors for efficient all small molecule fullerene-free organic solar cells

Despite their minimal HOMO energy level offset promising power conversion efficiencies up to 13.54% have been recorded for ternary organic solar cells using coumarin-based molecular donors and fullerene-free acceptors.

Effect of main and side chain chlorination on the photovoltaic properties of benzodithiophene-alt-benzotriazole polymers

Introduction of chlorine in the conjugated side chains significantly improves open-circuit voltage and power conversion efficiency, benefiting from a lower HOMO energy level, well-balanced charge transport and superior nanoscale morphology.

Ladder-like conjugated polymers used as hole-transporting materials for high-efficiency perovskite solar cells

Intramolecular S–O interactions were adopted for designing HTMs with high hole mobility and a suitable HOMO energy level in PVSK.

The effect of alkylthio side chains in oligothiophene-based donor materials for organic solar cells

The engineering of alkylthio side chains in the molecular conjugated backbone of small molecules is in favor of achieving a linear molecular backbone conformation, slightly red-shifting the absorption spectrum, and down-shifting the HOMO energy level of the resulting molecule.

Discotic liquid crystals of transition metal complexes, 55: Novel chlorine-substituted phthalocyanine derivatives showing mesomorphism and low HOMO energy level

We have synthesized a series of novel phthalocyaninato copper(II) (abbreviated as PcCu) compounds, 1,4,8,11,15,18,22,25-octakisalkoxy-2,3,9,10,16,17,23,24-octachloro-phthalocyaninato copper(II) (abbreviated as ([Formula: see text]-C[Formula: see text]O)[Formula: see text]-Cl)[Formula: see text]PcCu (4a–4d): [Formula: see text] 6 (a), 8 (b), 10 (c) and 12 (d)) and, for comparison, another series of PcCu compounds, 1,4,8,11,15,18,22,25-octakisalkoxyphthalocyaninato copper(II) (abbreviated as ([Formula: see text]-C[Formula: see text]O)[Formula: see text]PcCu (1a–1d)). The PcCu derivatives 1a–1d are substituted by alkoxy chains only at the [Formula: see text] positions (1,4,8,11,15,18,22,25). On the other hand, the PcCu derivatives 4a–4d are substituted by alkoxy chains at the [Formula: see text] positions and chlorine atoms at the [Formula: see text] positions (2,3,9,10,16,17,23,24). We have investigated the influence of chlorine atoms substituted at the [Formula: see text] positions of the Pc ring on mesomorphism, spectroscopic and electronic properties for these two series of PcCu derivatives 1 and 4 by using a polarizing optical microscope, DSC, temperature-variable small angle X-ray diffractometer, a UV-Vis spectrophotometer and cyclic voltammetry. Each of the derivatives 1a–1d is crystalline without showing mesomorphism. On the other hand, each of the chlorine-substituted PcCu derivatives 4a–4d shows plural phase transitions, and the longer chain-substituted PcCu derivatives 4c–4d show a rectangular ordered columnar [Col[Formula: see text](P2m)] mesophase. Furthermore, we have revealed that each of the PcCu derivatives 4a–4d shows a Q-band in the near-infrared region and a lower HOMO energy level than conventional phthalocyanine derivatives.

Dendron engineering in self-host blue iridium dendrimers towards low-voltage-driving and power-efficient nondoped electrophosphorescent devices

Low-voltage-driving and power-efficient nondoped electrophosphorescent devices have been realized by increasing the dendron's HOMO energy level to favor effective hole injection and promote exciton formation.