Narrow Absorption in ITO-Free Perovskite Solar Cells for Sensing Applications Analyzed through Electromagnetic Simulation

Abstract

This work reports on a computational analysis of how a modified perovskite cell can work as a refractometric sensor by generating surface plasmon resonances at its front surface. Metal-dielectric interfaces are necessary to excite plasmonic resonances. However, if the transparent conductor (ITO) is replaced by a uniform metal layer, the optical absorption at the active layer decreases significantly. This absorption enhances again when the front metallic surface is nanostructured, adding a periodic extruded array of high aspect-ratio dielectric pyramids. This relief excites surface plasmon resonances through a grating coupling mechanism with the metal surface. Our design allows a selective absorption in the active layer of the cell with a spectral response narrower than 1 nm. The photo-current generated by the cells becomes the signal of the sensor. The device employs an opto-electronic interrogation method, instead of the well-known spectral acquisition scheme. The sensitivity and figure of merit (FOM) parameters applicable to refractometric sensors were adapted to this new situation. The design has been customized to sense variations in the index of refraction of air between 1.0 and 1.1. The FOM reaches a maximum value of 1005 RIU − 1 , which is competitive when considering some other advantages, as the easiness of the acquisition signal procedure and the total cost of the sensing system. All the geometrical and material parameters included in our design were selected considering the applicable fabrication constrains.

Enabling selective absorption in perovskite solar cells for refractometric sensing of gases

“…This fact is in agreement with the physical interpretation of this peak as a selective transmitance through the slits 62 . The FOM results summarized in Table 2 are moderate compared with previously reported figures [1][2][3][4][6][7][8][9] .…”

“…The answer includes materials and sensitized coatings to selectively detect some specimens and substances using solar cells. The published results report applications for optical sensing 1 , gas sensing 2,3 , refractive index sensing [4][5][6][7] , chemical sensing 8 , and multi-functional sensors 9 . The advantage is clear: the signal is directly generated by the solar cell and, ideally, there is no need for sophisticated and voluminous read-out elements (goniometers and spectrometer for angular and spectral interrogation techniques) [10][11][12] .…”

Optoelectronic refractometric sensing device for gases based on dielectric bow-ties and amorphous silicon solar cells

“…Among them, hydrogenated amorphous silicon (aSiH) cells are commercial devices that employ an abundant, non-toxic and stable material 32 , 33 at a quite affordable price. Then, aSiH will be considered in this paper as the base device that will be transformed to work as a refractometric gas sensor interrogated opto-electronically 34 .…”

Plasmonic–perovskite solar cells, light emitters, and sensors

“…Recently, halide perovskites have been explored for applications as refractometric sensors, surface-enhanced Raman scattering (SERS), and biologic sensors. Elshorbagy et al theoretically reported a perovskite refractometric sensor with an extruded array of high aspect-ratio dielectric pyramids, which excited SPRs at its front surface by grating coupling with the metal surface 177 . The generated photocurrent acted as the sensing signal, where selective absorption with a spectral response narrower than 1 nm was achieved.…”