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Carbon nanosystems are among the most explored condensed matter systems in recent times owing to their extraordinary optical, electronic, thermal, and mechanical properties suitable for various applications. In the emerging field of THz science and technology, carbon nanosystems have been widely studied for different potential applications such as THz polarizer, modulator, flexible/wearable THz sources, and detectors. There have been some recent advances even on the front of THz lasing in carbon-based systems. The existing and continuously growing THz technologies demand compact, fast, broadband sources/detectors, and other high-performance devices. In this article, we provide an overview of the recent developments that are taking place on carbon nanomaterials-based THz photonic and optoelectronic device concepts and demonstrations. Later, we identify and propose a future perspective on three key areas, i.e., room temperature operatable THz lasers, a nonlinear generation and ultrashort pulsed THz source, and THz cameras, all based on carbon nanosystems, which show high scope for their realization in the near future and, hence, require more intense research. [ABSTRACT FROM AUTHOR]

Two pyrazoline core fluorescent materials were designed, synthesized and characterized by various approaches. The synthesized materials were confirmed by standard 1 H NMR and FT-IR techniques. Porous like morphologies were found from SEM analysis and the thermal stability of the materials analyzed with TGA–DSC analysis. Emission properties, quantum yield, lifetime and bandgap energy of the materials have also been studied. Solvent effect of absorption and emission spectral results indicated that the wavelength was red-shifted to increase the solvent polarity. The semiconducting nature was studied by UV–visible spectra, cyclic voltammetry analysis and theoretical calculation. I–V characteristic analysis was used to determine turn-on voltage of the materials for optoelectronics. [ABSTRACT FROM AUTHOR]

The exponential growth of utilizing synthetic organic molecules in optoelectronic applications poses strong demands for rational control over the excited states of the materials. The manipulation of excited states through molecular design has led to the development of high-performance optoelectronic devices with tunable emission colors, high quantum efficiencies and efficient energy/charge transfer processes. Recently, a significant breakthrough in lifetime tuning of excited states has been made; the purely organic molecules were found to have ultralong-lived excited state under ambient conditions with luminescence lifetimes up to 1.35 s, which are several orders of magnitude longer than those of conventional organic fluorophores. Given the conceptual advance in understanding the fundamental behavior of excited state tuning in organic luminescent materials, the investigations of organic ultralong room-temperature phosphorescence (OURTP) should provide new directions for researches and have profound impacts on many different disciplines. Here, we summarized the recent understandings on the excited state tuning, the reported OURTP molecules and their design considerations, the spectacular photophysical performance, and the amazing optoelectronic applications of the newly emerged organic optoelectronic materials that free of heavy metals. [ABSTRACT FROM AUTHOR]