Cross-Dehydrogenative Coupling (CDC) as Key-Transformations to Various D−π–A Organic Dyes: C–H/C–H Synthetic Study Directed toward Dye-Sensitized Solar Cells Applications

Hole-Transporting Materials based on Oligo(hetero)aryls with a Naphthodithiophene Core - Succinct Synthesis by Twofold Direct C-H Olefination

This work demonstrated the first synthetic application of direct C-H olefinations in the step-saving preparation of various hole-transporting materials (HTM) for efficient perovskite solar cells (PSC). Cross-dehydrogenative couplings of naphthodithiophene (NDT) with vinyl arenes under palladium-catalysis facilely generated various new oligo(hetero)aryls with internal alkenes. Reaction conditions were optimized, which gave the product isolated yields of up to 71 % with high (E)-stereoselectivity. These readily accessible NDT core-based small molecules involving olefin as π-spacers displayed immediate power conversion efficiencies of up to 17.2 % without a device oxidation process that is required for the commercially available spiro-OMeTAD and most other existing HTMs while fabricated in corresponding PSC devices.

Dye-sensitized solar cells strike back

Dye-sensitized solar cells (DSCs) are celebrating their 30th birthday and they are attracting a wealth of research efforts aimed at unleashing their full potential. In recent years, DSCs and dye-sensitized photoelectrochemical cells (DSPECs) have experienced a renaissance as the best technology for several niche applications that take advantage of DSCs' unique combination of properties: at low cost, they are composed of non-toxic materials, are colorful, transparent, and very efficient in low light conditions. This review summarizes the advancements in the field over the last decade, encompassing all aspects of the DSC technology: theoretical studies, characterization techniques, materials, applications as solar cells and as drivers for the synthesis of solar fuels, and commercialization efforts from various companies.

Development of Step-Saving Alternative Synthetic Pathways for Functional π-Conjugated Materials

Synthetic organic chemists endeavor to develop new reaction conditions, improve product yields, and enhance atom economy (synthetic methodologies), whereas the material scientists strive to create novel functional molecules/structures, increase device stabilities, and promote power conversion efficiencies via device engineering (organic optoelectronics). However, these two prominent research fields seem to have no intersections. Since joining national central university in 2012, our research philosophy aims to narrow, or rather to bridge the gap between synthetic methodologies and π-functional organic materials. In contrast to using multistep synthetic approaches based on Suzuki- or Stille coupling reactions, this personal account describes various step-saving and viable synthesis-shortcuts developed by our group, to access thiophene-based small molecules for optoelectronic applications. We expect these succinct and user-friendly alternative pathways designed by synthetic chemists would help material scientists to reach their target molecules in a more step-economical manner.

Synergistic promoting effect of ball milling and Fe(ii) catalysis for cross-dehydrogenative-coupling of 1,4-benzoxazinones with indoles

In this work, a novel C(sp3)–C(sp2) cross-dehydrogenative-coupling method is developed to react benzoxazin-2-one derivatives with various indoles. As a result, combined use of ball milling and Fe(ii) catalysis leads to rapid coupling of 1,4-benzoxazinones with derivatives of indole. Under the conditions, derivatives of 1 couple with various indoles at room temperature to produce good yields of the desired compounds within 0.5–2 h time period. Thus, derivatives of both starting materials couple smoothly under relatively mild conditions to give good yields of 3.