MoS₂ is an important two-dimensional transition metal dichalcogenide (TMD), whose physical and chemical properties are closely related to its layer number, size, defects, and crystal structure. Therefore, the controllable synthesis of phase-pure monolayer MoS₂ represents a key challenge. Herein, we report a simple and efficient wet-chemical synthesis strategy for 1T-MoS₂ and 2H-MoS₂, with the crystal phase controlled by the reaction temperature. At 220 °C, ultra-small (1–2 nm) monolayer 1T-MoS₂ colloids are obtained; at 250 °C, monolayer 2H-MoS₂ nanosheets are produced. Both materials exhibit good dispersibility in nonpolar solvents and can be readily spin-coated into thin films. Interestingly, the 1T-MoS₂ and 2H-MoS₂ exhibit different exciton dynamics in transient absorption (TA) spectra, but similar trap state-induced negative photoconductivity (NPC) under near-infrared (825 nm) illumination. These findings provide new perspectives for the design of MoS₂-based optoelectronic devices.

Chiral chalcogenide quantum dots (QDs) are typically prepared by coupling chiral ligands to the QD surface via aqueous-phase synthesis, water/oil interface-mediated synthesis, or post-synthetic ligand exchange. However, the hydrophilic nature of conventional chiral ligands restricts the chiral QDs to polar solvents, limiting their processability. The synthesis of oleophilic chiral chalcogenide QDs remains an unmet challenge. Here, we present a ligand design strategy that grafts chiral amino acids with long alkyl chains, preserving their chiral integrity and coordination capacity while conferring oleophilic solubility. Using this approach, we successfully prepared various chiral chalcogenide QDs that can be stably dispersed in nonpolar solvent. Quantum-confinement-tunable (size-dependent) circular dichroism (CD) spectra were achieved in chiral CdS and CdSe QDs. Notably, the thioether-containing chiral ligands (L/D-Cys-2C₁₂) can concurrently act as sulfur sources, permitting direct synthesis of oleophilic chiral sulfide QDs. It opens a new avenue for the synthesis of oleophilic chiral chalcogenide QDs and therefore expands their application prospects.

The chiral-induced spin selectivity (CISS) effect holds transformative potential for spin-controlled electrocatalysis, yet its implementation in metal-organic frameworks (MOFs) remains constrained by the reliance on chiral ligands or crystallographic asymmetry. Herein, we challenge this paradigm by demonstrating morphological chirality engineering in achiral CoNi-MOFs (C2/m symmetry) as a new route to CISS-enhanced oxygen evolution reaction (OER). Through amino acid-mediated growth control, these MOFs adopt left-/right-handed distorted morphologies despite their achiral space group and linkers, achieving 42% spin polarization and 30–50 mV lower OER overpotentials at 100 mA·cm⁻² compared to the achiral counterparts. This work establishes nanoscale morphological chirality control as a generalizable strategy to design spin-selective MOF electrocatalysts, potentially unlocking over 90% of the MOF family previously excluded from CISS applications.

Traditional perovskite single crystals typically exhibit polarization-dependent photoresponse characteristics due to crystallographic anisotropy, particularly showing sensitivity to linearly polarized light (LPL), and to left/right circularly polarized light (CPL) in chiral perovskites. However, achieving complete linear- and circular-polarization insensitivity in single perovskite crystals with intrinsic structural anisotropy remains an unresolved challenge. This study presents the observation of an unusual linear/circular-polarization-insensitive negative photoresponse in two-dimensional (2D) structured chiral lead-free double perovskite (R/S-MBA)₄AgBiI₈ single crystals. These crystals were prepared by a method combining cyclic heating and slow cooling processes. They have a defect density as low as 8.01 × 10⁹ cm⁻³ and a chiroptical anisotropy factor g_CD of 1.5 × 10⁻³. Mechanistic investigations through density functional theory (DFT) calculation, temperature dependent fluorescence spectroscopy and Raman spectroscopy attribute this anomaly to strong exciton self-trapping effects (STE), where photo-generated excitons form stable localized trapped states, dominating charge transport and effectively masking the polarization sensitivity. This discovery provides new insights into the structure–property relationship of perovskite materials and suggests potential pathways for designing novel polarization-insensitive optoelectronic devices.

All inorganic metal halide perovskite nanocrystals (NCs) have attracted much attention for their outstanding optoelectronic properties, which can be tuned by the composition, surface, size and morphology in nanoscale. Herein, we report the microfluidic synthesis of hollow CsPbBr₃ perovskite NCs through the nanoscale Kirkendall effect. The formation mechanism of the hollow structure (Kirkendall void) controlled by the temperature, flow rate, ratios of precursors and ligands was investigated. Compared with the solid CsPbBr₃ NCs of the same size, the hollow CsPbBr₃ NCs exhibit blue shifts in ultraviolet−visible (UV−vis) absorption and photoluminescence (PL) spectra, and remarkably longer PL average lifetime (~ 98.2 ns). Quantum confinement effect, inner surface induced additional trap states and lattice strain of the hollow CsPbBr₃ NCs were discussed in understanding their unique optoelectronic properties. The hollow CsPbBr₃ NC based photodetector exhibits an outstanding negative photoconductivity (NPC) detectivity of 8.9 × 10¹² Jones. They also show potentials in perovskite NC based photovoltaic and light emitting diodes (LEDs).

Carbon dots (CDs) have wide application potentials in optoelectronic devices, biology, medicine, chemical sensors, and quantum techniques due to their excellent fluorescent properties. However, synthesis of CDs with controllable spectrum is challenging because of the diversity of the CD components and structures. In this report, machine learning (ML) algorithms were applied to help the synthesis of CDs with predictable photoluminescence (PL) under the excitation wavelengths of 365 and 532 nm. The combination of precursors was used as the variable. The PL peaks of the strongest intensity ( ${\lambda }_{\mathrm{s}}$) and the longest wavelength ( ${\lambda }_{\mathrm{l}}$) were used as target functions. Among six investigated ML models, the random forest (RF) model showed outstanding performance in the prediction of the PL peaks.

All-inorganic lead halide perovskite CsPbX₃ (X = Cl, Br, and I) nanocrystals (NCs) have shown great application prospects in optoelectronic fields. Their properties can be feasibly tuned by the ratio of different halide ions. Post-synthesis halide anion exchange of Cl‒Br or Br‒I in CsPbX₃ NCs allows getting any desired composition of CsPbCl_xBr_3−x and CsPbBr_xI_3−x (0 ≤ x ≤ 3). However, due to the large difference of the Cl and I radii, they can only substitute each other in a limited ratio to form CsPbCl_yI_3−y (0 < y < δ or 3 − δ^' < y < 3). To date, little has been known on the phase diagram of the ternary halide perovskite of CsPbCl _aBr_bI_3−a−b (0 < a + b < 3). In this work, the ternary halide perovskite phase diagram is constructed by the strategy of halide anion exchange between perovskite NCs. From the diagram, the composition and proportion of the perovskite NC final phases from any starting perovskite NC mixture can be calculated. Specifically, a two-phase perovskite NC system showing stable dual photoluminescence (PL) peaks is achieved.