A systematic study of n-type zinc oxide thin films electrodeposition in presence of chloride ions is presented in this article. The incorporation of chlorine during the growth is characterized by several techniques, and its influence on the optoelectronic properties of the films is explored. Different deposition conditions have been tested; depending on the support electrolyte nature (nitrate or perchlorate) and on the chlorine concentration introduced in the bath, a large range of carrier concentrations has been reached (from 7.4 × 10 17 cm -3 for a nitrate electrolyte without chloride ions addition to 9 × 10 19 cm -3 in perchlorate conditions with a chloride concentration of 0.1 M). This evolution of the doping concentration evaluated by Mott-Schottky measurements and confirmed by Raman spectroscopy has a great effect on the optical transmission of the films. The increase in the doping concentration tends to shift the absorption edge to higher energies and to induces the decrease of the transmission in the near-infrared range because of the free carrier absorption. We finally propose a model to explain the effective n-type doping of ZnO with Cl, based on the intrinsic and extrinsic defects of the system.

We show that mechanochemically synthesized halide perovskite powders from a ball milling approach can be employed to fabricate a variety of lead halide perovskites with exceptional intrinsic stability. Our MAPbI3 powder exhibits higher thermal stability than conventionally processed thin films, without degradation after more than two and a half years of storage and only negligible degradation after heat treatment at 220 °C for 14 h. We further show facile recovery strategies of nonphase-pure powders by simple remilling or mild heat treatment. Moreover, we demonstrate the mechanochemical synthesis of phase-pure mixed perovskite powders, such as (Cs0.05FA0.95PbI3)0.85(MAPbBr3)0.15, from either the individual metal and organic halides or from readily prepared ternary perovskites, regardless of the precursor phase purity. Adding potassium iodide (KI) to the milling process successfully passivated the powders. We also succeeded in preparing a precursor solution on the basis of the powders and obtained uniform thin films for integration into efficient perovskite solar cells from spin-coating this solution. We find the KI passivation remains in the devices, leading to improved performance and significantly reduced hysteresis. Our work thus demonstrates the potential of mechanochemically synthesized halide perovskite powders for long-time storage and upscaling, further paving the way toward commercialization of perovskite-based optoelectronic devices.

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A low temperature (60 °C) encapsulation process based on a single thin (16 nm) coating of Al2O3 prepared by atomic layer deposition.

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