Quantum-corrected Reissner–Nordström AdS black hole with quintessence within rastall gravity framework

In this paper, we investigated the influence of quintessence dark energy on the photon dynamics, scalar field dynamics, and thermodynamic properties of a modified Reissner–Nordström-Anti-de Sitter (RN-AdS) black hole (BH) within the framework of Rastall gravity. We begin by formulating the BH solution surrounded by quintessence in this modified gravity and analyzing its spacetime structure. The dynamics of photons are explored, with emphasis on null geodesics, photon spheres, and their implications for optical observations. To probe stability, we study scalar perturbations through the massless Klein–Gordon equation and examine the corresponding perturbative potential in this modified geometry background. Finally, the thermodynamic behavior of the BH system is analyzed, and we discuss the role of quintessence as well as modified gravity in horizon properties, entropy, Hawking temperature, and possible phase transitions. In this case, our results demonstrate how quintessence alters both the dynamical and thermodynamical features of RN-AdS BH within the Rastall gravity framework.