The enduring interest in carbon quantum dots (CQDs) as photoluminescent material arises from their significant advantages over inorganic quantum dots (QDs), such as low toxicity and biocompatibility, which enables their application in bioimaging and drug delivery. This review is focused on the use of CQDs for light emitting devices (LED) technology and provides a guide on how to synthesize CQDs that emit blue, green, and red light, which is necessary to produce RGB LEDs. Consideration was given to the precursors, solvents, methods, and conditions of the processes, the excitation wavelength, the emission wavelength, and the photoluminescence quantum yield (QY). These unique, organic nanoparticles have the potential to revolutionize lighting and, above all, the electronics market due to their low cost and eco-friendliness, as well as the possibility of using various precursors, including waste.

Gallium nitride (GaN) has emerged as one of the most promising wide-bandgap semiconductors for next-generation space photovoltaics. In contrast to conventional III–V compounds such as GaAs and InP, which are highly efficient under terrestrial conditions but suffer from radiation-induced degradation and thermal instability, GaN offers an exceptional combination of intrinsic material properties ideally suited for harsh orbital environments. Its wide bandgap, high thermal conductivity, and strong chemical stability contribute to superior resistance against high-energy protons, electrons, and atomic oxygen, while minimizing thermal fatigue under repeated cycling between extreme temperatures. Recent progress in epitaxial growth—spanning metal–organic chemical vapor deposition, molecular beam epitaxy, hydride vapor phase epitaxy, and atomic layer deposition—has enabled unprecedented control over film quality, defect densities, and heterointerface sharpness. At the device level, InGaN/GaN heterostructures, multiple quantum wells, and tandem architectures demonstrate outstanding potential for spectrum-tailored solar energy conversion, with modeling studies predicting efficiencies exceeding 40% under AM0 illumination. In this review article, the current state of knowledge on GaN materials and device architectures for space photovoltaics has been summarized, with emphasis placed on recent progress and persisting challenges. Particular focus has been given to defect management, doping strategies, and bandgap engineering approaches, which define the roadmap toward scalable and radiation-hardened GaN-based solar cells. With sustained interdisciplinary advances, GaN is anticipated to complement or even supersede traditional III–V photovoltaics in space, enabling lighter, more durable, and radiation-hard power systems for long-duration missions beyond Earth’s magnetosphere.

This work investigates the design, simulation, and characterization of thin-film platinum resistive heaters fabricated by magnetron sputtering. Finite element simulations were performed in COMSOL Multiphysics to analyze heat generation and temperature distribution as a function of heater geometry under steady-state conditions. The influence of convective heat transfer on temperature uniformity and thermal efficiency was systematically examined. Platinum thin films deposited by magnetron sputtering were characterized in terms of their structural, morphological, and electrical properties. The crystallographic structure was analyzed using X-ray diffraction, while the surface morphology and microstructure were examined by atomic force microscopy and scanning electron microscopy. Electrical conductivity measurements were carried out to evaluate resistive behavior relevant to heater performance. All characterizations were conducted for as-deposited samples and after post-deposition annealing at 500 °C to assess the effect of thermal treatment on film stability and properties. The simulation results were experimentally validated by infrared thermography, allowing a direct comparison between calculated and measured temperature distributions. The combined numerical and experimental approach enables the correlation among the deposition conditions, microstructural evolution, geometry, and electrical heating performance, providing guidelines for the optimization of thin-film platinum resistive heaters.