A thorough and comprehensive study of novel phthaloperinone derivatives: from synthesis and property evaluation to applications in light-emitting diodes

Abstract

Despite its promising electronic and semiconducting properties, 12H-phthaloperin-12-one remains a largely unexplored molecule, with limited studies regarding the impact of structural modifications on its properties and its application in light-emitting devices. To address this gap, we report the synthesis of 12 novel phthaloperinone derivatives, designed to fine-tune the photophysical, electrochemical, thermal and electroluminescence properties through the incorporation of electron-donating and electron-withdrawing substituents. The majority of substituents was found to interfere with the electronic distribution in the phthaloperinone core during the electronic excitation process. The introduction of a triphenylamine unit, as in compounds 3f/4f, resulted in the lowest energy gap of 2.22 eV, making this isomeric mixture a promising candidate for use as an organic semiconductor material. Electrochemical studies demonstrated that compounds 3e/4e–3h/4h and 3l/4l exhibited enhanced electrochemical stability, while thermal analysis showed that the pyrene-substituted derivative (3e/4e) displayed the highest thermal resistance (T_d = 458 °C). Organic light-emitting diodes were fabricated to evaluate their electroluminescence properties. Compounds 3l/4l, which contain a phenyltriazolyl unit, achieved the best performance, displaying a maximum luminance of 99 cd m⁻² at 7.5 V, a luminous efficiency of 0.014 cd A⁻¹, and a turn-on voltage of 3.3 V. These findings provide valuable insights into the structure–property relationships of phthaloperinone derivatives and highlight their potential for a wide range of applications, including electronic and optoelectronic devices.