仲云雷

A lead-free halide perovskite Cs₃Bi₂I₉ single-crystalline thin film, with adjustable thickness and millimeter size, is directly integrated on various substrates including Si wafer, through a supersaturation-controlled method. Benefiting from the incommensurate lattice match and suitable thinness, this silicon-compatible perovskite photodetector is superior to most reported state-of-the-art lead-free halide perovskite photodetectors.

Abstract

Monolithical integration of the promising optoelectronic material with mature and inexpensive silicon circuitry contributes to simplifying device geometry, enhancing performance, and expanding new functionalities. Herein, a lead-free halide perovskite Cs₃Bi₂I₉ single-crystalline thin film (SCTF), with thickness ranging from 900 nm to 4.1 µm and aspect ratio up to 1666, is directly integrated on various substrates including Si wafer, through a facile and low-temperature solution-processing method. The growth kinetics of the lead-free halide perovskite SCTF are elucidated by in situ observation, and the solution supersaturation is controlled to reduce the inverse-temperature crystallization nucleation density and elongate the evaporation growth. The excellent lattice match and band alignment between Si(111) and Cs₃Bi₂I₉(001) facets promote photogenerated charge dissociation and extraction, resulting in boosting the photoelectric sensitivity by 10–200 times compared with photodetectors based on other substrates. More importantly, this silicon-compatible perovskite SCTF photodetector exhibits a high switching ratio of 3000 and a fast response of 1.5 µs, which are higher than most reported state-of-the-art lead-free halide perovskite photodetectors. This work not only gives an in-depth understanding of the perovskite precursor solution chemistry, but also demonstrates the great potential of monolithical integration of lead-free halide perovskite SCTF with a silicon wafer for high-performance photodetectors.

Author(s): Sheng Liu, Andrés Granados del Águila, Dhiman Bhowmick, Chee Kwan Gan, T. Thu Ha Do, M. A. Prosnikov, David Sedmidubský, Zdenek Sofer, Peter C. M. Christianen, Pinaki Sengupta, and Qihua Xiong

We report the direct observation of strong coupling between magnons and phonons in a two-dimensional antiferromagnetic semiconductor FePS3, via magneto-Raman spectroscopy at magnetic fields up to 30 Tesla. A Raman-active magnon at 121  cm−1 is identified through Zeeman splitting in an applied magnet...

[Phys. Rev. Lett. 127, 097401] Published Mon Aug 23, 2021

Author(s): Wei Qin and Allan H. MacDonald

It has recently been shown [Y. Cao, J. M. Park, K. Watanabe, T. Taniguchi, and P. Jarillo-Herrero, Pauli-limit violation and re-entrant superconductivity in moiré graphene, Nature (London) 595, 526 (2021).] that superconductivity in magic-angle twisted trilayer graphene survives to in-plane magnetic...

[Phys. Rev. Lett. 127, 097001] Published Mon Aug 23, 2021

Author(s): Haining Pan and Sankar Das Sarma

Using a realistic band structure for twisted WSe2 materials, we develop a theory for the interaction-driven correlated insulators to conducting metals transitions through the tuning of the filling factor around commensurate fractional fillings of the moiré unit cell in the 2D honeycomb lattice, focu...

[Phys. Rev. Lett. 127, 096802] Published Tue Aug 24, 2021

Author(s): G. Fabiani, M. D. Bouman, and J. H. Mentink

We investigate the propagation of magnons after ultrashort perturbations of the exchange interaction in the prototype two-dimensional Heisenberg antiferromagnet. Using the recently proposed neural quantum states, we predict highly anisotropic spreading in space constrained by the symmetry of the per...

[Phys. Rev. Lett. 127, 097202] Published Wed Aug 25, 2021

Nature Nanotechnology, Published online: 23 August 2021; doi:10.1038/s41565-021-00955-8

Nature Communications, Published online: 24 August 2021; doi:10.1038/s41467-021-25306-y

Nature Nanotechnology, Published online: 16 August 2021; doi:10.1038/s41565-021-00960-x

Nature Communications, Published online: 13 August 2021; doi:10.1038/s41467-021-25083-8

Nature Materials, Published online: 05 August 2021; doi:10.1038/s41563-021-01061-9

Nature Materials, Published online: 05 August 2021; doi:10.1038/s41563-021-01058-4

Nature Communications, Published online: 03 August 2021; doi:10.1038/s41467-021-24531-9

This study proposes a grinding-promoted intercalation exfoliation (GPIE) method to prepare pure semiconductive hexagonal phase (2H phase) molybdenum disulfide (MoS₂) nanocomposites with cellulose nanocrystals (CNC). The introduction of CNC not only improves the exfoliation yield of the MoS₂ nanosheets, but also forms the sandwich structure with MoS₂ and thus increases the interlayer spacing of MoS₂ nanosheets for excellent potassium-ion storage performance.

Abstract

Efficient exfoliations of bulk molybdenum disulfide (MoS₂) into few-layered nanosheets in pure phase are highly attractive because of the promising applications of the resulted 2D materials in diversified optoelectronic devices. Here, a new exfoliation method is presented to prepare semiconductive 2D hexagonal phase (2H phase) MoS₂–cellulose nanocrystal (CNC) nanocomposites using grinding-promoted intercalation exfoliation (GPIE). This method with facile grinding of the bulk MoS₂ and CNC powder followed by conventional liquid-phase exfoliation in water can not only efficiently exfoliate 2H-MoS₂ nanosheets, but also produce the 2H-MoS₂/CNC 2D nanocomposites simultaneously. Interestingly, the intercalated CNC sandwiched in MoS₂ nanosheets increases the interlayer spacing of 2H-MoS₂, providing perfect conditions to accommodate the large-sized ions. Therefore, these nanocomposites are good anode materials of potassium-ion batteries (KIBs), showing a high reversible capacity of 203 mAh g⁻¹ at 200 mA g⁻¹ after 300 cycles, a good reversible capacity of 114 mAh g⁻¹ at 500 mA g⁻¹, and a low decay of 0.02% per cycle over 1500 cycles. With these impressive KIB performances, this efficient GPIE method will open up a new avenue to prepare pure-phase MoS₂ and promising 2D nanocomposites for high-performance device applications.

Nature Communications, Published online: 02 August 2021; doi:10.1038/s41467-021-24970-4

Nature Nanotechnology, Published online: 03 June 2021; doi:10.1038/s41565-021-00916-1