Hydrogen detector in Kretschmann configuration based on an inorganic perovskite

We theoretically investigate a hydrogen (H \(_2\) ${}_2$ ) detector in a plasmonic structure involving an inorganic perovskite. The structure is composed of a prism, a silver layer, a perovskite layer (CsPbBr \(_3\) ${}_3$ ), and a palladium layer (Pd). The palladium layer absorbs H₂, which transforms it into a Pd-H layer. Due to the large difference in dielectric constants between Pd and Pd-H, the reflection versus the incident angle \(\theta\) $\theta$ exhibits great differences ( \(\Delta R\) $\mathrm{\Delta }R$ ) between the structures with a Pd layer and with a Pd-H layer. Our calculation results show that the working wavelength has a substantial impact on \(\Delta R\) $\mathrm{\Delta }R$ . The working wavelength not only affects the dielectric constants of the materials in our structure, but also influences the skin depth of surface plasmon polaritons (SPPs) in the CsPbBr \(_3\) ${}_3$ layer, which couple with the Pd or Pd-H layers. A long working wavelength provides a longer skin depth, which couples more energy of the SPPs with the Pd or Pd-H layers. With an increase in Ag layer thickness, the dissipation of our proposed structure reduces the maximum value of \(\Delta R\) $\mathrm{\Delta }R$ . According to our calculations, there is an optimal thickness of the CsPbBr \(_3\) ${}_3$ layer for which the value of \(\Delta R\) $\mathrm{\Delta }R$ is the largest. The results show the competition between the coupling and the dissipation of the SPP intensity along the direction perpendicular to the layers in the CsPbBr \(_3\) ${}_3$ layer. At certain conditions, \(\Delta R\) $\mathrm{\Delta }R$ reaches a value of 0.13, which is about 20% of the reflection value. The detector we designed demonstrates good performance, with many potential applications.