Luminescent crystals and manufacturing thereof

The present invention relates to the field of luminescent crystals (LCs), and more specifically to Quantum Dots (QDs) of formula A1aM2bXc, wherein the substituents are as defined in the specification. The invention provides methods of manufacturing such luminescent crystals, particularly by dispersing suitable starting materials in the presence of a liquid and by the aid of milling balls; to compositions comprising luminescent crystals and to electronic devices, decorative coatings; and to components comprising luminescent crystals.</p

Solid polymer composition

The present invention relates in a first aspect to a solid polymer component comprising luminescent crystals of 3-500 nm size, surfactant and a hardened/cured polymer. In a second aspect of the invention, a luminescent component comprises a first element comprising the solid polymer component according to the first aspect and an encapsulation enclosing the first element. In a third aspect of the invention, a luminescent component comprises a first film comprising the solid polymer composition of the first aspect. A fourth aspect of the invention relates to a light emitting device comprising the luminescent component according to the second or third aspect of the invention and a light source.</p

Supramolecular assemblies of semiconductor quantum dots and a bis(bipyridinium) derivative : luminescence quenching and aggregation phenomena

We have synthesized CdSe and CdSe–ZnS core–shell luminescent nanocrystal quantum dots and studied their interaction with a ditopic bis(bipyridinium) compound in solution. The latter strongly quenches the luminescence of the quantum dots by a static mechanism, indicating that the nanocrystal and molecular components undergo association in the ground state. Photoexcitation of these inorganic–organic hybrids causes an electron-transfer process from the conduction band of the nanocrystal to the LUMO of the molecule. The ability of the bipyridinium-type species to trigger association of the quantum dots is evidenced by spectrofluorimetric titrations and DLS measurements in solution, and confirmed by TEM experiments on surfaces. The quantum dot–molecule complexes can be disassembled in solution by addition of a calixarene host capable of encapsulating the bipyridinium units of the molecular connector. Our results demonstrate that supramolecular chemistry offers convenient ways to control the aggregation of semiconductor nanocrystals, a crucial task for the generation of nanostructured arrays with well defined properties

Supramolecular assemblies of semiconductor quantum dots and a bis(bipyridinium) derivative: luminescence quenching and aggregation phenomena

We have synthesized CdSe and CdSe\u2013ZnS core\u2013shell luminescent nanocrystal quantum dots and studied their interaction with a ditopic bis(bipyridinium) compound in solution. The latter strongly quenches the luminescence of the quantum dots by a static mechanism, indicating that the nanocrystal and molecular components undergo association in the ground state. Photoexcitation of these inorganic\u2013organic hybrids causes an electron-transfer process from the conduction band of the nanocrystal to the LUMO of the molecule. The ability of the bipyridinium-type species to trigger association of the quantum dots is evidenced by spectrofluorimetric titrations and DLS measurements in solution, and confirmed by TEM experiments on surfaces. The quantum dot\u2013molecule complexes can be disassembled in solution by addition of a calixarene host capable of encapsulating the bipyridinium units of the molecular connector. Our results demonstrate that supramolecular chemistry offers convenient ways to control the aggregation of semiconductor nanocrystals, a crucial task for the generation of nanostructured arrays with well defined properties

Antimony doped Tin Oxide/Polyethylenimine Electron Selective Contact for reliable and light soaking-free high Performance Inverted Organic Solar Cells

We have demonstrated a high-performance low temperature solution processed electron selective contact consisting of 10 at% antimony doped tin oxide (ATO) and the neutral polymer polyethylenimine (PEI). Inverted organic photovoltaics (OPVs) utilizing ATO/PEI as electron selective contact exhibited high power conversion efficiencies for both the reference P3HT: PCBM and the non-fullerene based P3HT- IDTBR active layer OPV material systems. Importantly it is shown that the proposed ATO/PEI carrier selective contact provides light soaking-free inverted OPVs. Furthermore, by increasing the thickness of ATO layer from 40 to 120 nm the power conversion efficiency of the corresponding inverted OPVs remain unaffected a parameter which indicates the potential of the proposed ATO/PEI carrier selective contact for high performance light-soaking-free and reliable roll-to-roll printing solutions processed inverted OPVs.Comment: 20 pages, 4 figures, 2 table

Ecofriendly Perovskites with Giant Self-Defocusing Optical Response

[EN] The full optical control of light using sustainable green technologies is one of the incipient challenges of the Photonics community. There are, however, few optical materials able to provide a significant nonlinear refractive index change under small enough intensities (< 1 GW cm(-2)), and, more importantly, allowing the external control of the magnitude and sign of their nonlinear response. This manuscript demonstrates that Cs2SnI6 lead-free nanocrystals (NCs) present an extraordinary self-defocusing response not yet observed up to now in any material. Despite its complex structural form, these NCs are fully characterized here, both experimentally and theoretically, revealing a giant negative refractive change Delta n = -0.05 under proper illumination conditions. The nonlinear response is tuned with the intensity, concentration of NCs in the solvent, and propagation distance leading to a crossover where the media transforms to self-focusing with Delta n = +0.002. These results can provide fascinating opportunities in sensing and light-matter interactions for a future ecofriendly photonic technology.This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no. 862656 (project DROP-IT) and by the Spanish MICINN through project no. PID2020-120484RB-I00 and by Generalitat Valenciana PROMETEO/2021/082.Suárez, I.; Martinez-Pastor, JP.; Oszajca, MF.; Lüchinger, NA.; Graves, B.; Agouram, S.; Milián Enrique, C.... (2022). Ecofriendly Perovskites with Giant Self-Defocusing Optical Response. Advanced Optical Materials. https://doi.org/10.1002/adom.20220212

Inkjet‐Printed p‐NiO/n‐ZnO Heterojunction Diodes for Photodetection Applications

Transparent Conducting Oxides (TCOs) are an enticing family of optoelectronic materials which have been proven to increase efficiency when incorporated into perovskite light emitting diode (PE-LED) and organic OLED architectures as transport layers. Solution-processed metal oxide inks have already been demonstrated, although there is still a need for high-quality inkjet-printable metal oxide inks with a thermal post-process below 200 °C. The set of inks in this work are adapted from low-boiling point colloidal suspensions of metal oxide nanoparticles synthesized via flame spray pyrolysis. High quality, pinhole- and wrinkle-free inkjet-printed layers are obtained at low temperatures through vacuum oven post process, as proven by scanning electron microscopy. The crystallinity of the layers is confirmed by X-ray diffraction, showing the expected hexagonal and cubic structures respectively for ZnO and NiO. The thin film layers reach over 70% (ZnO) and 90% (NiO) transparency in the visible spectrum. Their implementation in the inkjet-printed p-n diode shows excellent I-V rectifying behavior with an ON/OFF ratio of two orders of magnitude at ±3 V and a forward threshold voltage of 2 V. Furthermore, the device exhibits an increase in photocurrent around four orders of magnitude when illuminated under a 1-sun solar simulator

Synthesis and properties of ZnTe and ZnTe/ZnS core/shell semiconductor nanocrystals

Nanocrystals obtained by growing a protecting ZnS shell onto a photoactive ZnTe core afford nanocrystals that can represent alternatives to cadmium-based quantum dots