Visible Light Communication (VLC) technology is an emerging technology using visible light modulation that, in the modern world, will mainly facilitate high-speed internet connectivity. VLC provides tremendous advantages compared to conventional radio frequency, such as a higher transmission rate, high bandwidth, low-power consumption, no health hazards, less interference, etc., which make it more prominent in recent days. Due to their outstanding features, including low cost, low power consumption, etc., µ-light-emitting diodes (LEDs) have gained considerable attention for VLC implementation, but mostly for the ability to be used for lighting as well as communications. In this review paper, we will focus mainly on recent developments in VLC applications and various factors affecting the modulation bandwidth of VLC devices. Numerous factors, such as quantum confined stark effect (QCSE), carrier lifetime, carrier recombination time, crystal orientation, etc. affect the modulation bandwidth of LEDs, and more information will be discussed in the following sections. This paper will focus on VLC applications based on LEDs but mainly on semipolar μ-LEDs and μ-LED-based arrays with high bandwidths. Another important application of VLC is underwater optical wireless communication (UOWC), which has drawn a huge interest in marine exploration and underwater connectivity, but still faces some challenges because visible light is being used. In addition, this paper will focus on how the current VLC system modulation bandwidth can be enhanced. Many methods have been introduced, such as decreasing the active layer thickness or effective active area or using doping, but the bandwidth is restricted by the recombination time when the system configuration reaches its limit. Therefore, it is important to find alternative ways such as optimizing the system, using the blue filter or using the equalization technology, which will be addressed later. Overall, this review paper provides a brief overview of the VLC-based system performance and some of its potential prospects.

Two-dimensional quantum dots have received a lot of attention in recent years due to their fascinating properties and widespread applications in sensors, batteries, white light-emitting diodes, photodetectors, phototransistors, etc. Atomically thin two-dimensional quantum dots derived from graphene, layered transition metal dichalcogenide, and phosphorene have sparked researchers’ interest with their unique optical and electronic properties, such as a tunable energy bandgap, efficient electronic transport, and semiconducting characteristics. In this review, we provide in-depth analysis of the characteristics of two-dimensional quantum dots materials, their synthesis methods, and opportunities and challenges for novel device applications. This analysis will serve as a tipping point for learning about the recent breakthroughs in two-dimensional quantum dots and motivate more scientists and engineers to grasp two-dimensional quantum dots materials by incorporating them into a variety of electrical and optical fields.

Optimized energy utilization in Underwater Wireless Sensor Networks (UWSNs) is a challenging task and an active research area. Non-uniform energy consumption in a sensor network creates coverage holes that mean nodes with no transmission energy. These holes degrade the performance and reduce lifetime of UWSNs. In this work, we propose an Optimized Depth Based Routing (ODBR) scheme which ensures uniform energy consumption amongst sensor nodes and hence maximizes network lifetime. We allocate more initial energy to nodes that have higher traffic load compared to the ones with less traffic load. The results show that this strategy helps to balance energy utilization amongst sensor nodes and improves lifetime of the network.

MICRO-LEDs (μ-LEDs) HAVE been engaged in the next-generation display technology and evolved for various applications from several electronics manufacturers and institutions. The area of n-LEDs (less than 10 # 10 nm2) is desired for the high pixelsper-inch (PPI) value of the microdisplay, but the sidewall effect from the etching process will drop the quantum efficiency

In this study, we demonstrate a 3-in-1 mini-light emitting diodes (LEDs) with ${160} \times {65}\,\,\mu \text{m}^{{2}}$ mini-LED subpixel chip size. Blue mini-LEDs are combining with red and green quantum dots (QDs) by using ink-jet printing technique to achieve a full-color and high-quality mini-LEDs array in the form of a monolithic chip. Subsequently, low-temperature passivated by atomic layer deposition (ALD) at 50 °C is used to effectively avoid the photo-oxidation and maintain the color purity, 99.5% National Television Standards Committee (NTSC) and 89.6% of Rec. 2020 color gamut of red as well as green QDs (GQDs) during 300 h reliability test under 50 °C/50% relative humidity (RH) condition. The environment stability L50 of both samples is 6761 and 5889 h for red and green QDs. Finally, we advocate the potential of the demonstrated highly stable full-color QD mini-LEDs to be applied in the display technology. This research also meets the requirement for a simple QD deposition method which is expected to achieve a breakthrough.