Laser Derived Electron Transport Layers with Embedded p-n Heterointerfaces Enabling Planar Perovskite Solar Cells with Efficiency over 25

Electron transport layers (ETLs) with pronounced electron conducting capability are essential for high performance planar photovoltaics, with the great challenge being that the most widely used metal oxide ETLs unfortunately have intrinsically low carrier mobility. Herein is demonstrated that by simply addressing the carrier loss at particle boundaries of TiO₂ ETLs, through embedding in ETL p-n heterointerfaces, the electron mobility of the ETLs can be boosted by three orders of magnitude. Such embedding is also encouragingly favorable for both inhibiting the formation of rutile phase TiO₂ in ETL, and initiating the growth of the top high-quality and large-grain perovskite films with less defect states. By virtue of these merits, creation of formamidinium lead iodide perovskite solar cells (PSCs) with a champion efficiency of 25.05% is achieved, setting a new benchmark for planar PSCs employing TiO₂ ETLs. Unencapsulated PSCs employing such ETLs also deliver much-improved environmental stability, i.e., more than 80% of their initial efficiency after 9000 h of air storage under RH of 40%, and over 90% of their initial efficiency at maximum power point under continuous illumination for 500 h. Further work exploring other laser-generated p-type nanocrystals for embedding warrants the proposed strategy as a universal alternative for addressing the low-carrier mobility of metal oxide based ETLs, from the view point of particle boundaries engineering. This article is protected by copyright. All rights reserved.

Ru/CdS Quantum Dots Templated on Clay Nanotubes as Visible-Light-Active Photocatalysts: Optimization of S/Cd Ratio and Ru Content

A nanoarchitectural approach based on in situ formation of quantum dots (QDs) within/outside clay nanotubes was developed. Efficient and stable photocatalysts active under visible light were achieved with ruthenium-doped cadmium sulfide QDs templated on the surface of azine-modified halloysite nanotubes. The catalytic activity was tested in the hydrogen evolution reaction in aqueous electrolyte solutions under visible light. Ru doping enhanced the photocatalytic activity of CdS QDs thanks to better light absorption and electron-hole pair separation due to formation of a metal/semiconductor heterojunction. The S/Cd ratio was the major factor for the formation of stable nanoparticles on the surface of the azine-modified clay. A quantum yield of 9.3 % was reached by using Ru/CdS/halloysite containing 5.2 wt % of Cd doped with 0.1 wt % of Ru and an S/Cd ratio of unity. In vivo and in vitro studies on the CdS/halloysite hybrid demonstrated the absence of toxic effects in eukaryotic cells and nematodes in short-term tests, and thus they are promising photosensitive materials for multiple applications.

Core-shell nanoarchitecture: Schiff-base assisted synthesis of ruthenium in clay nanotubes

Natural halloysite clay nanotubes were used as a template for clay/Ru core-shell nanostructure synthesis. Ru-nanoparticles were produced via a ligand-assisted metal ion intercalation technique. Schiff bases formed from different organic compounds proved to be effective ligands for the metal interfacial complexation which then was converted to Ru particles. This produces a high amount of intercalated metal nanoparticles in the tube’s interior with more that 90% of the sample loaded with noble metal. Depending on the selection of organic linkers, we filled the tube’s lumen with 2 or 3.5-nm diameter Ru particles, or even larger metal clusters. Produced nanocomposites are very efficient in reactions of hydrogenation of aromatic compounds, as tested for phenol and cresols hydrogenation.

Nanoparticles Formed onto/into Halloysite Clay Tubules: Architectural Synthesis and Applications

Nanoparticles, being objects with high surface area are prone to agglomeration. Immobilization onto solid supports is a promising method to increase their stability and it allows for scalable industrial applications, such as metal nanoparticles adsorbed to mesoporous ceramic carriers. Tubular nanoclay - halloysite - can be an efficient solid support, enabling the fast and practical architectural (inside / outside) synthesis of stable metal nanoparticles. The obtained halloysite-nanoparticle composites can be employed as advanced catalysts, ion-conducting membrane modifiers, inorganic pigments, and optical markers for biomedical studies. Here, we discuss the possibilities to synthesize halloysite decorated with metal, metal chalcogenide, and carbon nanoparticles, and to use these materials in various fields, especially in catalysis and petroleum refinery.