Supercapacitors (SCs), including electric double-layer capacitors (EDLCs), pseudocapacitors, and hybrid capacitors, are esteemed for their high power density and attractive features such as robust safety, fast charging, low maintenance, and prolonged cycling lifespan, sparking significant interest. Carbon quantum dots (CQDs) are fluorescent nanomaterials with small size, broad excitation spectrum, stable fluorescence, and adjustable emission wavelengths. They are widely used in optoelectronics, medical diagnostics, and energy storage due to their biocompatibility, low toxicity, rich surface functional groups, abundant electron-hole pairs, large specific surface area, and tunable heteroatom doping. In this short review, we briefly discussed the advantages and disadvantages of bottom-up and top-down of CQD synthesis methods. The arc-discharge technique, laser ablation technique, plasma treatment, ultrasound synthesis technique, electrochemical technique, chemical exfoliation, and combustion are among the initial top-down approaches. The subsequent section delineates waste-derived and bottom-up methods, encompassing microwave synthesis, hydrothermal synthesis, thermal pyrolysis, and the metal-organic framework template-assisted technique. In addition, this short review focuses on the operational mechanism of supercapacitors, their properties, and the utilization of CQDs in supercapacitors.

Different counter electrode (CE) materials based on carbon and Cu₂S were prepared for the application in CdS and CdSe quantum dot-sensitized solar cells (QDSSCs). The CEs were prepared using low-cost and facile methods. Platinum was used as the reference CE material to compare the performances of the other materials. While carbon-based materials produced the best solar cell performance in CdS QDSSCs, platinum and Cu₂S were superior in CdSe QDSSCs. Different CE materials have different performance in the two types of QDSSCs employed due to the different type of sensitizers and composition of polysulfide electrolytes used. The poor performance of QDSSCs with some CE materials is largely due to the lower photocurrent density and open-circuit voltage. The electrochemical impedance spectroscopy performed on the cells showed that the poor-performing QDSSCs had higher charge-transfer resistances and CPE values at their CE/electrolyte interfaces.

We presented synthesis and physical characterization of iron oxide magnetic nanoparticles (Fe₃O₄) for biomedical applications in the size range of 10-30 nm. Magnetic nanoparticles were synthesized by the coprecipitation method, and the particles’ size was controlled by two different injection methods of sodium hydroxide (NaOH). The synthesized magnetic nanoparticles were then modified by using series of linkers including tetraethyl orthosilicate (TEOS), 3-aminopropyltriethoxysilane (APTES), and glutaraldehyde (GA) to generate the structure of Fe₃O₄/SiO₂/NH₂/CHO, which can be used for immobilization of protein A. Additionally, we used transmission electron microscopy (TEM), X-ray powder diffraction (XRD), vibrating-sample magnetometry (VSM), and Fourier-transform infrared spectroscopy (FTIR), for characterization of properties and structure of the nanoparticles. An immobilization of protein A on magnetic nanoparticles was studied with a UV-Vis spectrum (UV-Vis) and fluorescence electron microscopy and Bradford method. Results showed that an XRD spectrum with a peak at (311) corresponded to the standard peak of magnetic nanoparticles. In addition, the magnetic nanoparticles withd≥30 nm have higher saturation magnetizations in comparison with the smaller ones withd≤10 nm. However, the smaller magnetic nanoparticles offered higher efficiency for binding of protein A, due to the high surface/volume ratio. These particles with functional groups on their surface are promising candidates for biomedical applications, e.g., drug delivery, controlled drug release, or disease diagnosis in point-of-care test.

Considering global climate change concerns, issues related to the energy crisis and technologies reliant on non-fossil renewable energy sources are in high demand. Solar energy emerges as one of the alternatives among all renewable energy resources due to its economic viability and environmental sustainability. There are various types of solar photovoltaic (PV) technologies available for commercial applications, such as organic solar cells, silicon-based solar cells, dye-sensitized solar cells, and perovskite solar cells. Notably, one of the drawbacks of PV devices is their inability to generate power at night or during cloudy days (i.e., low-light conditions). One solution to this problem is to provide backup to the PV devices, such as batteries or energy storage packs. Another less explored alternative backup is the application of long persistent luminescence (LPL) materials as a secondary light source or down shifter. LPL materials can provide an afterglow that can last for hours which can be harvested by PV devices for power generation under low-light conditions. This short overview article discusses the fundamental mechanisms of LPL materials and the feasibility and challenges of integrating LPL materials into PV, which is hoped can provide useful insights for future research directions.

The past few years have been great years for semiconductor quantum dot‐sensitized solar cells (QDSSCs). For the first time, efficiency exceeding 15% has been reported. This has narrowed the gap with other emerging solar cell technologies such as dye‐sensitized solar cells and thin film solar cells. In this miniperspective, the reason for such improvement is briefly reviewed. Few advancements have been identified that are responsible for the performance breakthrough in QDSSCs. These included better performance of sensitizer materials used, the use of doping agents, and surface passivation strategy.