Organic-inorganic hybrid materials composed of bismuth and diaminopyridine are studied as novel materials for electron extraction layers in polymer solar cells using regular device structures. The hybrid materials are solution processed on top of two different low band gap polymers (PTB7 or PTB7-Th) as donor materials mixed with fullerene PCBM as the acceptor. The intercalation of the hybrid layer between the photoactive layer and the aluminum cathode leads to solar cells with a power conversion efficiency of 7.8% because of significant improvements in all photovoltaic parameters, that is, short-circuit current density, fill factor, and open-circuit voltage, similar to the reference devices using ZnO as the interfacial layer. However when using thick layers of such hybrid materials for electron extraction, only small losses in photocurrent density are observed in contrast to the reference material ZnO of pronounced losses because of optical spacer effects. Importantly, these hybrid electron extraction layers also strongly improve the device stability in air compared with solar cells processed with ZnO interlayers. Both results underline the high potential of this new class of hybrid materials as electron extraction materials toward robust processing of air stable organic solar cells.

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Hybrid organic-inorganic materials are a new class of material used as interfacial layers in polymer solar cells. A hybrid material, composed of antimony as inorganic part and diaminopyridine as organic part, is synthesized and described as a new material for electron extraction layer in polymer solar cells and compared to the recently demonstrated hybrid materials using bismuth instead of antimony. The hybrid compound is solution-processed onto the photoactive layer based on a classical blend, composed of PTB7-Th low bandgap polymer as donor mixed with PC70BM fullerene as acceptor material. By using a regular device structure and an aluminum cathode, the solar cells exhibited a power conversion efficiency of 8.42%, equivalent to the reference device using ZnO nanocrystals as interfacial layer, and strongly improved compared to bismuth-based hybrid material. The processing of extraction layers up to a thickness of 80 nm of such hybrid material reveals that the change from bismuth to antimony has strongly improved the charge extraction and transport properties of the hybrid materials. Interestingly, nanocomposites made of the hybrid material mixed with ZnO nanocrystals in a 1:1 ratio further improved the electronic properties of the extraction layers, leading to power conversion efficiency of 9.74%. This was addressed to a more closely packed morphology of the hybrid layer, leading to further improved electron extraction. It is important to note that these hybrid electron extraction layers, both pure and ZnO-doped, also greatly improved the stability of solar cells, both under dark storage in air and under lighting under inert atmosphere compared to solar cells treated with ZnO intermediate layers.

The new organic-inorganic hybrid material (C 6 H 7 N 2 S) 2 [SbCl 4 ]Cl was synthesized by slow evaporation method and characterized by single-crystal X-ray diffraction, infrared absorption, Hirshfeld surface analysis, optical absorption and photoluminescence measurements. The Centro symmetric compound crystallizes in the triclinic system of space group P1 with two formula units cell (Z = 2).The crystal structure is composed of a discrete [SbCl 4 ] − anion and two isolated chloride Cl − anions which carried the same negative charge to balance the total charge of this compound surrounded by the 4 pyridiniumethioamide cations. Organic and inorganic parts which are linked by means of hydrogen bonding contacts N-H···Cl with N···Cl length are varied in the range of 3.221-3.456 Å to form a Zero-dimensional network. The infrared study performed at room temperature charge in the 4000-400 cm −1 frequency regions confirms the existence of the organic cation [C 6 H 7 N 2 S] + and that of the [SbCl 4 ] − anion. The Photoluminescence spectrum exhibits a broad and strong band of luminescence located at 1.95 eV (635 nm), which can be even observed with the naked eye at room temperature and is due to exaction emission. The various intermolecular interactions of the two independent cations and six chloride atoms were examined via Hirshfeld surface analysis.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.