Synthesis and Structure Design of I-III-VI Quantum Dots for White Light-emitting Diodes

Quantum-dot-based light-emitting diodes (LEDs) have been considered as promising alternatives to the traditional light sources due to their photo- and thermal-stability, emission wavelength tunability, and so forth. From the past...

Tunable resonantly pumped Er:GGAG laser

The main goal of this work was to present spectroscopic and laser characteristics including the wavelength tunability of Er-doped Gd3Ga3Al2O12 (Er:GGAG) crystal. Seven Er:GGAG crystals of various Er/Gd concentrations were investigated. The maximum output peak power of 0.99 W with an absorbed pumping peak power amplitude of 5.22 W for the crystal at 0.55 at.% Er/Gd concentration was researched. The tuning was accomplished using a SiO2 birefringent plate. The laser wavelength was tunable in three eye-safe spectral bands from 1609 to 1650 nm.

Waveguide Schottky photodetector with tunable barrier based on Ti3C2T x /p-Si van der Waals heterojunction

MXene, a new advanced two-dimensional material, has attracted great attention in energy storage, transparent electrodes, and electromagnetic shielding due to its high conductivity, high specific surface area, and hydrophilic surface. Given the solution-processability and tunable work function, MXene also holds great potential for wide-range photodetection and integrated optics. Here, we demonstrate a waveguide integrated Schottky photodetector based on Ti3C2T x /Si van der Waals heterojunction. Specifically, the barrier of the Schottky photodetector can be adjusted by using simple surface treatment. The work function of the Ti3C2T x is reduced from 4.66 to 4.43 eV after vacuum annealing, and the barrier height of Ti3C2T x /p-Si Schottky junction is correspondingly increased from 0.64 to 0.72 eV, leading to 215 nm working wavelength blue-shift. The photodetector exhibits working wavelength tunability in short-wavelength infrared regions due to the engineered Schottky barrier. To our best knowledge, this is the first demonstration of utilizing MXene in waveguide-integrated photodetection, showing the potential applications for various scenarios thanks to the flexible working wavelength range induced by the tunable barrier.

Influence of Y2O3 Content on Structural, Optical, Spectroscopic, and Laser Properties of Er3+, Yb3+ Co-Doped Phosphate Glasses

The influence of the addition of Y2O3 on the structural, spectroscopic, and laser properties of newly prepared Er, Yb-doped strontium-sodium phosphate glass was investigated. While the addition of Y2O3 has a small influence on the absorption spectra and fluorescence lifetime, it has a strong impact on the emission cross-section and on OH− content. The glasses were used as the active medium for diode-pumped laser emitting at 1556 nm. The increase in Y2O3 content leads to a significant 35% increase in laser slope efficiency up to 10.4%, but at the expense of the substantial reduction of the wavelength tunability from 82 to 54 nm.

Retina-Inspired Organic Heterojunction-Based Optoelectronic Synapses for Artificial Visual Systems

For the realization of retina-inspired neuromorphic visual systems which simulate basic functions of human visual systems, optoelectronic synapses capable of combining perceiving, processing, and memorizing in a single device have attracted immense interests. Here, optoelectronic synaptic transistors based on tris(2-phenylpyridine) iridium (Ir(ppy)3) and poly(3,3-didodecylquarterthiophene) (PQT-12) heterojunction structure are presented. The organic heterojunction serves as a basis for distinctive synaptic characteristics under different wavelengths of light. Furthermore, synaptic transistor arrays are fabricated to demonstrate their optical perception efficiency and color recognition capability under multiple illuminating conditions. The wavelength-tunability of synaptic behaviors further enables the mimicry of mood-modulated visual learning and memorizing processes of humans. More significantly, the computational dynamics of neurons of synaptic outputs including associated learning and optical logic functions can be successfully demonstrated on the presented devices. This work may locate the stage for future studies on optoelectronic synaptic devices toward the implementation of artificial visual systems.

Light-Driven Dissipative Self-Assembly of a Peptide Hydrogel

Light energy provides an attractive fuel source for energy dissipating systems because of the lack of waste production, wavelength tunability and the potential for spatial and temporal resolution. In this...