Zero-Dimensional Broadband Yellow Light Emitter (TMS)CuI for Latent Fingerprint Detection and Solid-State Lighting.

We report a new hybrid organic-inorganic Cu(I) halide, (TMS)CuI (TMS = trimethylsulfonium), which demonstrates high efficiency and stable yellow light emission with a photoluminescence quantum yield (PLQY) over 25%. The zero-dimensional crystal structure of the compound is comprised of isolated face-sharing photoactive [CuI] tetrahedral dimers surrounded by TMS cations. This promotes strong quantum confinement and electron-phonon coupling, leading to a highly efficient emission from self-trapped excitons.

Biexciton-like Auger Blinking in Strongly Confined CsPbBr Perovskite Quantum Dots.

Perovskite quantum dots (QDs) with high room-temperature luminescence efficiency have been applied in single-photon sources. While the optical properties of large, weakly confined perovskite nanocrystals have been extensively explored at the single-particle level, few studies have focused on single-perovskite QDs with strong quantum confinement. This is mainly due to their poor surface chemical stability.

Bright and Dark Exciton Coherent Coupling and Hybridization Enabled by External Magnetic Fields.

Magnetic field- and polarization-dependent measurements on bright and dark excitons in monolayer WSe combined with time-dependent density functional theory calculations reveal intriguing phenomena. Magnetic fields up to 25 T parallel to the WSe plane lead to a partial brightening of the energetically lower lying exciton, leading to an increase of the dephasing time. Using a broadband femtosecond pulse excitation, the bright and partially allowed excitonic state can be excited simultaneously, resulting in coherent quantum beating between these states.

High broadband photoconductivity of few-layered MoS field-effect transistors measured using multi-terminal methods: effects of contact resistance.

Among the layered two dimensional semiconductors, molybdenum disulfide (MoS2) is considered to be an excellent candidate for applications in optoelectronics and integrated circuits due to its layer-dependent tunable bandgap in the visible region, high ON/OFF current ratio in field-effect transistors (FET) and strong light-matter interaction properties. In this study, using multi-terminal measurements, we report high broadband photocurrent response (R) and external quantum efficiency (EQE) of few-atomic layered MoS2 phototransistors fabricated on a SiO2 dielectric substrate and encapsulated with a thin transparent polymer film of Cytop. The photocurrent response was measured using a white light source as well as a monochromatic light of wavelength λ = 400 nm-900 nm.

Coherent two-dimensional Fourier transform spectroscopy using a 25 Tesla resistive magnet.

We performed nonlinear optical two-dimensional Fourier transform spectroscopy measurements using an optical resistive high-field magnet on GaAs quantum wells. Magnetic fields up to 25 T can be achieved using the split helix resistive magnet. Two-dimensional spectroscopy measurements based on the coherent four-wave mixing signal require phase stability.