Electronic Properties of Free-Standing Surfactant-Capped Lead Halide Perovskite Nanocrystals Isolated in Vacuo

Abstract

We report an investigation of lead halide perovskite CHNHPbBr nanocrystals and associated ligand molecules by combining several different state-of-the-art experimental techniques, including synchrotron radiation-based XPS and VUV PES of free-standing nanocrystals isolated in vacuum. By using this novel approach for perovskite materials, we could directly obtain complete band alignment to vacuum of both CHNHPbBr nanocrystals and the ligands widely used in their preparation. We discuss the possible influence of the ligand molecules to apparent perovskite properties, and we compare the electronic properties of nanocrystals to those of bulk material. The experimental results were supported by DFT calculations.

Ni-Doped CsPbBr3 Perovskite: Synthesis of Highly Stable Nanocubes

“…The Ni has two peaks with binding energies of 854.5 and 871.5 eV corresponding to 2P 3/2 and 2P 1/2 , which are similar to the literature values. , There are two Cs 3d peaks at 722.2 and 736.2 eV, corresponding to the 3d 5/2 and 3d 3/2 peaks. Figure a,b shows the high-resolution X-ray photoelectron spectra of Pb4f and Br3d each having two peaks at approximately 141 and 136.2 eV and 66.1 and 73.0 eV corresponding to 4f 7/2 and 4f 5/2 and 3d 5/2 and 3d 3/2 , which are similar to the reported values. , The XPS image can clearly indicate the successful introduction of Ni atom in the CsPbBr 3 perovskite.…”

“…Figure 4a,b shows the highresolution X-ray photoelectron spectra of Pb4f and Br3d each having two peaks at approximately 141 and 136.2 eV and 66.1 and 73.0 eV corresponding to 4f 7/2 and 4f 5/2 and 3d 5/2 and 3d 3/2 , which are similar to the reported values. 21,22 The XPS image can clearly indicate the successful introduction of Ni atom in the CsPbBr 3 perovskite.…”

Conformer-Dependent VUV Photodynamics and Chiral Asymmetries in Pure Enantiomers of Gas Phase Proline

“…These aerosols were produced by nebulization of a 1 g/L solution of Pro in He (2 bars) within an atomizer (TSI, model 3062) followed by a drying stage composed of two silica gel columns before being introduced into a new aerodynamic lens (ADL) that transmits and focuses sub-micron nanoparticles (30-300 nm with 100 % efficiency) into the ionization region. [75][76][77] As compared to the previously-used ADL for Ala, the present one offers a much higher nanoparticle throughput, mechanical stability and reproducibility, and operational duty cycle. After traversing two 2-mm skimmers, the aerosols impinged onto a hot tip made of porous tungsten and heated up via a heating cartridge so that the tip temperature was set to 415 K and 493 K, the two temperatures used for the two sets of data obtained with the TD method, in conditions referred to as TD415 and TD493.…”

Recent Advances in Ligand Design and Engineering in Lead Halide Perovskite Nanocrystals

“…[ 112 ] Presence of Br – on the NC surface has been demonstrated experimentally through X‐ray photoelectron spectroscopy (XPS) measurements for both MAPbBr 3 and CsPbBr 3 NCs. [ 45,113,114 ] In these measurements, two Br 3d peaks were observed due to the presence of both inner and surface ions for both bulk and nanosized particles (Figure 2G). [ 45 ] Differences in the intensity ratio between the two peaks in the NCs compared to the bulk material indicated the presence of high concentrations of Br – present on the NC surface.…”