Acid leaching of Al- and Ta-substituted Li7La3Zr2O12 (LLZO) solid electrolyte

Solid-state batteries (SSBs) are promising next-generation batteries due to their potential for achieving high energy densities and improved safety compared to conventional lithium-ion batteries (LIBs) with a flammable liquid electrolyte. Despite their huge market potential, very few studies have investigated SSB recycling processes to recover and reuse critical raw metals for a circular economy. For conventional LIBs, hydrometallurgical recycling has been proven to be able to produce high-quality products, with leaching being the first unit operation. Therefore, it is essential to establish a fundamental understanding of the leaching behavior of solid electrolytes as the key component of SSBs with different lixiviants. This work investigates the leaching of the most promising Al- and Ta-substituted Li7La3Zr2O12 (LLZO) solid electrolytes in mineral acids (H2SO4 and HCl), organic acids (formic, acetic, oxalic, and citric acid), and water. The leaching experiments were conducted using actual LLZO production waste in 1 M of acid at 1:20 S/L ratio at 25 ◦C for 24 h. The results showed that strong acids, such as H2SO4, almost completely dissolved LLZO. Encouraging selective leaching properties were observed with oxalic acid and water. This fundamental knowledge of LLZO leaching behavior will provide the basis for future optimization studies to develop innovative hydrometallurgical SSB recycling processes

Single-Source, Solvent-Free, Room Temperature Deposition of Black γ-CsSnI₃ Films

The presence of a non-optically active polymorph (yellow-phase) competing with the optically active polymorph (black $\gamma$-phase) at room temperature in CsSnI3 and the susceptibility of Sn to oxidation, represent two of the biggest obstacles for the exploitation of CsSnI3 in optoelectronic devices. Here room-temperature single-source in vacuum deposition of smooth black $\gamma$ - CsSnI3 thin films is reported. This has been done by fabricating a solid target by completely solvent-free mixing of CsI and SnI2 powders and isostatic pressing. By controlled laser ablation of the solid target on an arbitrary substrate at room temperature, the formation of CsSnI3 thin films with optimal optical properties is demonstrated. The films present a band gap of 1.32 eV, a sharp absorption edge and near-infrared photoluminescence emission. These properties and X-ray diffraction of the thin films confirmed the formation of the orthorhombic (B-$\gamma$) perovskite phase. The thermal stability of the phase was ensured by applying in situ an Al2O$_3$ capping layer. This work demonstrates the potential of pulsed laser deposition as a volatility-insensitive single-source growth technique of halide perovskites and represents a critical step forward in the development and future scalability of inorganic lead-free halide perovskites.Comment: Accepted by Advanced Materials Interfaces, 16 pages, 4 figures, and supplemen

Strain Engineered Electrically Pumped SiGeSn Microring Lasers on Si

SiGeSn holds great promise for enabling fully group-IV integrated photonics operating at wavelengths extending in the mid-infrared range. Here, we demonstrate an electrically pumped GeSn microring laser based on SiGeSn/GeSn heterostructures. The ring shape allows for enhanced strain relaxation, leading to enhanced optical properties, and better guiding of the carriers into the optically active region. We have engineered a partial undercut of the ring to further promote strain relaxation while maintaining adequate heat sinking. Lasing is measured up to 90 K, with a 75 K T0. Scaling of the threshold current density as the inverse of the outer circumference is linked to optical losses at the etched surface, limiting device performance. Modeling is consistent with experiments across the range of explored inner and outer radii. These results will guide additional device optimization, aiming at improving electrical injection and using stressors to increase the bandgap directness of the active material

A Recommender System for Inverse Design of Polycarbonates and Polyesters

The convergence of artificial intelligence and machine learning with material science holds significant promise to rapidly accelerate development timelines of new high-performance polymeric materials. Within this context, we report an inverse design strategy for polycarbonate and polyester discovery based on a recommendation system that proposes polymerization experiments that are likely to produce materials with targeted properties. Following recommendations of the system driven by the historical ring-opening polymerization results, we carried out experiments targeting specific ranges of monomer conversion and dispersity of the polymers obtained from cyclic lactones and carbonates. The results of the experiments were in close agreement with the recommendation targets with few false negatives or positives obtained for each class.<br /

Towards Automated Monomer Synthesis: A Streamlined Approach for the Synthesis of Cyclic Carbonates

Accessing cyclic carbonate monomers on large scales is critical for development of any new carbonate-based material platform. This is particularly important in the context of using automated experimental systems for materials synthesis, which can often require large inputs of starting materials. However, the synthesis of carbonate monomers can be a challenging and tedious endeavor, requiring multiple synthetic steps and purifications. To address this, we report a drastically improved and scalable process for the synthesis of carbonate monomers via a two-step route that avoids the use of hazardous phosgene or chloroformate reagents. The cyclic carbonate monomers can be obtained in high yields and with minimal need for chromatographic purification. This process enables rapid access to a broad array of functional groups on the carbonate monomer and monomers generated from procedure can readily be polymerized via ring-opening polymerization.<br /

CMOS-Compatible Bias-Tunable Dual-Band Detector Based on GeSn/Ge/Si Coupled Photodiodes

Infrared (IR) multispectral detection is attracting increasing interest with the rising demand for high spectral sensitivity, room temperature operation, CMOS-compatible devices. Here, we present a two-terminal dual-band detector, which provides a bias-switchable spectral response in two distinct IR bands. The device is obtained from a vertical GeSn/Ge/Si stack, forming a double junction n-i-p-i-n structure, epitaxially grown on a Si wafer. The photoresponse can be switched by inverting the bias polarity between the near and the short-wave IR bands, with specific detectivities of 1.9 × 1010 and 4.0 × 109 cm·(Hz)1/2/W, respectively. The possibility of detecting two spectral bands with the same pixel opens up interesting applications in the field of IR imaging and material recognition, as shown in a solvent detection test. The continuous voltage tuning, combined with the nonlinear photoresponse of the detector, enables a novel approach to spectral analysis, demonstrated by identifying the wavelength of a monochromatic beam. © 2021 The Authors. Published by American Chemical Society

CMOS-Compatible Bias-Tunable Dual-Band Detector Based on GeSn/Ge/Si Coupled Photodiodes

Infrared (IR) multispectral detection is attractingincreasing interest with the rising demand for high spectralsensitivity, room temperature operation, CMOS-compatible devices.Here, we present a two-terminal dual-band detector, which providesa bias-switchable spectral response in two distinct IR bands. Thedevice is obtained from a vertical GeSn/Ge/Si stack, forming adouble junction n-i-p-i-n structure, epitaxially grown on a Si wafer.The photoresponse can be switched by inverting the bias polaritybetween the near and the short-wave IR bands, with specificdetectivities of 1.9 × 1010 and 4.0 × 109 cm·(Hz)1/2/W, respectively.The possibility of detecting two spectral bands with the same pixelopens up interesting applications in the field of IR imaging andmaterial recognition, as shown in a solvent detection test. Thecontinuous voltage tuning, combined with the nonlinear photoresponse of the detector, enables a novel approach to spectral analysis,demonstrated by identifying the wavelength of a monochromatic beam