Effects of Oxygen Plasma on the Chemical, Light-Emitting, and Electrical-Transport Properties of Inorganic and Hybrid Lead Bromide Perovskite Nanocrystal Films

Abstract

We show that oxygen plasma affects in different ways the structural, chemical, optical and electrical properties of methylammonium and cesium lead bromide nanocrystals. Hybrid organic-inorganic nanocrystals were severely and quickly degraded by oxygen plasma at 50 W. Their photoluminescence was quenched with almost 100% loss of initial quantum yield. This is linked to the decomposition of the nanocrystals. Inorganic nanocrystals were more resistant to oxygen plasma in the same conditions. Despite a moderate loss of photoluminescence and electrical conductivity, oxygen plasma had a positive impact, removing unbound ligands resulting in a more ohmic behavior of the film. This paves the way to the application of oxygen plasma in the development of perovskite-based optoelectronic devices. ASSOCIATED CONTENTSupporting Information. Experimental details, TEM, absorption and photoluminescence spectra of NCs in solution, XPS spectra, XRD of thin films, PL spectra of thin films.

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

“…[ 364 ] Effects of oxygen plasma treatment on the native organic ligand shells for both CsPbX 3 and MAPbX 3 NCs have also been explored. [ 365 ] Specifically, the O 2 plasma mainly affects the top few nanometers of the NC film and is able to partially remove residual organics (ligands) that could be detrimental to device performances. [ 365 ] Films formed from MAPbBr 3 NCs were destroyed following O 2 plasma treatment, evidenced from loss of PL and quenching of its electrical transport properties.…”

“…[ 365 ] Specifically, the O 2 plasma mainly affects the top few nanometers of the NC film and is able to partially remove residual organics (ligands) that could be detrimental to device performances. [ 365 ] Films formed from MAPbBr 3 NCs were destroyed following O 2 plasma treatment, evidenced from loss of PL and quenching of its electrical transport properties. [ 365 ] Films formed from CsPbBr 3 NCs, on the other hand, demonstrated enhanced stability and only partial quenching of the PL (≈50% of initial PL QY maintained following 15 min of O 2 plasma treatment at 50 W).…”

Incorporation of potassium halides in the mechanosynthesis of inorganic perovskites: feasibility and limitations of ion-replacement and trap passivation

“…[6][7][8] Thus, fully inorganic halide perovskites, such as cesium-based perovskites are sought aer for their increased stability. [9][10][11][12][13] The known poor solubility of cesium halides in common solvents may be bypassed by synthesizing inorganic perovskites in an all-dry manner such as by mechanosynthesis (e.g., grinding or ball-milling) [14][15][16][17][18] and/or thermal vacuum deposition. 19 Recently, halide perovskites with an increasing complexity in formulation containing up to 6 or 7 different ions have proven to be benecial for device performance.…”

“… 6–8 Thus, fully inorganic halide perovskites, such as cesium-based perovskites are sought after for their increased stability. 9–13 The known poor solubility of cesium halides in common solvents may be bypassed by synthesizing inorganic perovskites in an all-dry manner such as by mechanosynthesis ( e.g. , grinding or ball-milling) 14–18 and/or thermal vacuum deposition.…”

Donor–Acceptor Competition via Halide Vacancy Filling for Oxygen Detection of High Sensitivity and Stability by All‐Inorganic Perovskite Films

“…[27] The CsPbBr 3 film with more Br vacancies having higher oxygen sensitivity confirms that the Br vacancies are the active sites to adsorb O 2 for sensing, which is in good agreement with our previous DFT modeling. Since the Ar plasma treatment prefers to remove lightweight and weak-bonded atoms owing to low formation energies, [28][29][30] we propose the mechanism of oxygen sensing as O 2 interact with the Br vacancies at the GBs of CsPbBr 3 film. To assess this hypothesis, the element mapping was first performed by SEM energy-dispersive X-ray spectroscopy (SEM-EDS) to visualize the distribution of Br vacancies as the previous study.…”