Surface Versus Bulk State Transitions in Inkjet-Printed All-Inorganic Perovskite Quantum Dot Films

Abstract

The anion exchange of the halides, Br and I, is demonstrated through the direct mixing of two pure perovskite quantum dot solutions, CsPbBr3 and CsPbI3, and is shown to be both facile and result in a completely alloyed single phase mixed halide perovskite. Anion exchange is also observed in an interlayer printing method utilizing the pure, unalloyed perovskite solutions and a commercial inkjet printer. The halide exchange was confirmed by optical absorption spectroscopy, photoluminescent spectroscopy, X-ray diffraction, and X-ray photoemission spectroscopy characterization and indicates that alloying is thermodynamically favorable, while the formation of a clustered alloy is not favored. Additionally, a surface-to-bulk photoemission core level transition is observed for the Cs 4d photoemission feature, which indicates that the electronic structure of the surface is different from the bulk. Time resolved photoluminescence spectroscopy indicates the presence of multiple excitonic decay features, which is argued to originate from states residing at surface and bulk environments.

Roadmap on printable electronic materials for next-generation sensors

“…These merits generally enable the generation of columnar grains, which lead to high mobility-lifetime product and reduced charge recombination [179]. Another promising printing technique, inkjet printing, has an advantage of forming thick and multi-layered lead-free perovskite [147,191]. It should be noted that the thickness of perovskites is essential for high-energy gamma-ray detection considering the effective attenuation of gamma-rays in the detector medium [187].…”

Multipass Inkjet Printing of Lead Halide Perovskite Pixels onto Flexible Substrates

“…Lead halide perovskites are not only outstanding materials for solar cells but have recently been noticed for their high efficiency as light emitters. , By varying the halide ion mixture, bright red, green, and blue light emission can be obtained. − Ultimately, these materials may be used in active display technology as an alternative to organic light-emitting diodes (OLEDs) and CdSe-based quantum dots. A variety of methods has been suggested to transfer the high-performance properties of organic perovskites from solid to flexible substrates using inkjet printing: perovskite nanocrystals, − nanochannels, , or micron-sized single crystals as well as advanced techniques such as direct-print photopolymerization or photolithography. , However, the most direct and cost-efficient method is printing precursor ink directly onto the substrate. − …”

Influence of Binary Ligands in Designing Cesium Lead Halide (CsPbX3, X = Cl, Br, I) Perovskite Nanocrystals-Oleic Acid and Oleylamine

“…Figure 1 shows a schematic representation of the surface termination of the CsPbBr 3 NC lattice and a representation of colloidal CsPbX 3 NCs and their PL spectra. Countless articles deal with synthesizing and fabricating Cs LHP thin films using solution-processing methods [6][7][8]. The high photoluminescence quantum yield (PLQY) of Cs LHP NCs is related to several factors, including the nature of precursors, halide concentration in solution, synthesis methods, organic ligands used in the reaction, and the composition of the finally formed NCs [9][10][11].…”