Novel Donor–Acceptor Based 4-Nitrophenol luminophors as a Yellow-Orange Fluorescent Material for Optoelectronic Applications

Abstract A new category of 4-nitrophenol (4-NP) luminophores, infused with differing quantities of Pyrene (Py), was synthesized using the standard solid-state reaction method to explore novel luminophores emitting at longer wavelengths. Their optical and electrochemical properties were analyzed through fluorimetry and Cyclic Voltammetry techniques, respectively. The fluorescence spectrum of Py-doped 4-NP exhibited a broad fluorescence band peaking at 599 nm for a Py concentration of 1x10⁻ ³ mol, confirming exciplex formation between 4-NP and Py in the excited state. Based on electrochemical data, the energy levels of the Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) were determined for the prepared luminophores, falling in between 5.72–5.73 eV and 3.01–3.08 eV, respectively. Thermal stableness was assessed via TGA analysis, while SEM images revealed crystal sizes of approximately 115 nm. Consequently, this comprehensive investigation suggests the potential utility of these newly developed yellow-orange fluorescent luminophores in optoelectronic applications.