Chiral quantum dots (QDs) are promising materials applied in many areas, such as chiral molecular recognition and spin selective filter for charge transport, and can be prepared by facile ligand exchange approaches. However, ligand exchange leads to an increase in surface defects and reduces the efficiencies of radiative recombination and charge transport, which restricts further applications. Here, we investigate the light-induced photoluminescence (PL) enhancement in chiral L- and D-cysteine CdSe QD thin films, providing a strategy to increase the PL. The PL intensity of chiral CdSe QD films can be significantly enhanced over 100 times by continuous UV laser irradiation, indicating a strong passivation of surface defects upon laser irradiation. From the comparative measurements of the PL intensity evolutions in vacuum, dry oxygen, air, and humid nitrogen atmospheres, we conclude that the mechanism of PL enhancement is photo-induced surface passivation with the assistance of water molecules.

The coexistence of two spin components with different Larmor frequencies in colloidal CdSe and CdS quantum dots (QDs) leads to the entanglement of spin signals, complicating the analysis of dynamic processes and hampering practical applications. Here, we explored several methods, including varying the types of hole acceptors, air or anaerobic atmosphere and laser repetition rates, in order to facilitate the obtention of one single Larmor frequency in the coherent spin dynamics using time-resolved ellipticity spectroscopy at room temperature. In an air or nitrogen atmosphere, manipulating the photocharging processes by applying different types of hole acceptors, e.g., Li[Et₃BH] and 1-octanethiol (OT), can lead to pure spin components with one single Larmor frequency. For as-grown QDs, low laser repetition rates favor the generation of the higher Larmor frequency spin component individually, while the lower Larmor frequency spin component can be enhanced by increasing the laser repetition rates. We hope that the explored methods can inspire further investigations of spin dynamics and related photophysical processes in colloidal nanostructures.

Chiral rare earth nanomaterials, which impart optical activity through chiral structures or ligands, possess promising application potential in optoelectronic displays, biosensing, information encryption, and catalysis due to unique properties like circularly polarized luminescence, exceptional photostability, and tunable optics. This review systematically summarizes recent advancements, focusing on synthetic strategies, distinctive optical properties, and experimental demonstrations of applications across various fields. Finally, prospects and challenges for future development are discussed. These studies advance the understanding of circularly polarized luminescence and enable the flexible design and fabrication of chiral rare earth nanomaterials with engineered functionalities, addressing practical challenges in optoelectronic displays and biomedicine.

Chiral quantum dots (QDs) are expected to play a significant role in chiral molecular recognition, spin-selective filtering for charge transport, and various other fields. Photo-irradiation can enhance the photoluminescence (PL) of chiral CdSe QD films, which serves as a convenient method to modulate the optical properties. However, the effects of photo-irradiation on the absorption and spin properties of chiral QDs remain unclear. In this study, we investigate the influence of photo-irradiation on the PL, absorption, and spin properties of chiral L/D-cysteine-capped CdS QD films. Under the irradiation of the 458 nm continuous wave laser, the PL intensity of chiral CdS QD films can be significantly enhanced by over 50 times and the absorption peak exhibits a blue shift of approximately 3 nm. The transient transmission dynamics before and after irradiation indicate that the bleach recovery lifetime became longer after irradiation, which can be attributed to the increase in radiative recombination. Furthermore, the strength of the electron spin is diminished due to a decrease in the number of charge-separated electrons. The significant enhancement in PL intensity, coupled with the increased radiative recombination and the reduction in spin signals, strongly suggests that surface defects are effectively passivated. The influence of photo-irradiation on the optical properties of chiral QDs provides valuable insights for the design of chiral nanomaterials and their applications.

This study investigates a method for fabricating hybrid periodic micro/nanostructures based on polarization-controlled two-beam holography using a femtosecond laser. By adjusting the polarization combination of the two laser beams, four types of hybrid micro/nanostructures were successfully fabricated on the ZnO surface. The evolution of surface structures with increasing pulse numbers and laser fluences was also discussed. Theoretical calculations revealed the crucial role of polarization distribution in determining the orientation of nanostructures, which is consistent with the experimental results. This method enables structural diversity through polarization adjustment without the need for optical path adjustments, offering new ideas for applications such as photonic crystals and polarization-sensitive optical devices, to our knowledge.