By coupling localised and propagating surface plasmon modes within photonic band gap effects, researchers have demonstrated enhanced fluorescence, spontaneous emission rates, and nonlinear optical responses. To enhance and direct molecular emission from up-conversion nanoparticles (UCNPs), we investigate a new strategy of coupling gold plasmonic gratings with one-dimensional photonic crystals (1D PhCs). The multilayers act as optical mirrors, suppressing unwanted transmission and boosting excitation and emission efficiency through directionality, while plasmonic effects amplify localised field in excitation. COMSOL simulations revealed optimal design for our fabricated nanophotonic device by calculating determining parameters in grating and multilayer (ML) structures and analyzing how grating periodicity, PhC thickness, and nanoparticles’ location influence resonances in excitation and emission enhancement, making it a promising candidate for various spectroscopic applications, particularly in the field of biosensing..