J. Eur. Opt. Society-Rapid Publ. 22, 38( 2026) 377
Figure 2. Scheme of the proposed nanograting in the HTL surface to provide a larger light path control and enhance the effective absorbance of the PSC. Inset: detail of the structure with the most significant geometrical parameters.
compares the Sn-OM6 cell absorption with the average conventional LED lighting emission spectrum. While the cell exhibits a broad absorption band centered at 460 nm, absorption decreases significantly in the higher wavelength region, highlighting a clear opportunity for optimization.
Figure
1.( a) The planar structure of the perovskite solar cell that has been used in this work, including the most significant layers. In particular, an OM6-modified FASI is used as active layer with the aim of enhancing stability.( b) Spectral profile of the absorbance of the considered planar perovskite solar cell( left-axis) and the spectral emission of typical LED of indoor lighting systems( right axis).
with a negligible BCP( bathocuproine) buffer layer and SiO 2 encapsulation. As it is established in [ 22 ] the optical properties for PEDOT are essentially constant. The rest of the optical parameters used as inputs come from both literature and manufacturers, including the ones of the original planar device [ 21 ]. Periodic boundary conditions( PBC) were applied along the x- and y-axes, with perfectly matched layers( PML) in the z-axis to simulate propagation. The device was illuminated by a plane wave( z-propagating, x-polarized) with a spectrum derived from the average of experimental indoor LED measurements taken at Carlos III University of Madrid, as shown in Figure 1b.
The absorbed optical power in the halide perovskite layer was calculated using electric field intensity(| E | 2) and dielectric permittivity() data obtained from 3D FDTD monitors, same size as the perovskite active layer. The absorbed power density is defined as:
P ¼�0:5x jEj 2 ImðÞ; ð1Þ
where x is the angular frequency of incident radiation and Im() is the imaginary part of the perovskite dielectric constant. Total absorption was determined by integrating this optical power over the simulation volume. Figure 1b
3 Results and discussion
We focus on the application of these devices in energy harvesting for indoor conditions. Therefore, we have studied the most widely distributed luminaires: LEDs. LED lighting implies a very different illumination from the usual solar spectrum. While the first reaches a standard of 100 mW cm �2( at AM1.5G), indoor lighting only reaches a small fraction of it. Indeed, the spectrum is very different, with a usual peak around 450 nm due to the blue LED inside, and a spread emission band around 600 nm due to the phosphor inside the encapsulated luminaire. White LEDs can achieve combinations of desired ambient lighting( cool or warm lights) by balancing both emissions. To get a good overview of real situations in which future applications will be developed, we have measured a set of scenarios in actual classrooms and laboratories of Carlos III University of Madrid( UC3M), discarding those measurements close to the windows during daylight hours( where the outdoor lighting is at least one order of magnitude higher than the indoor one). As was commented on, Figure 1b depicts the average emission spectrum of the received light on horizontal planes at user heights in those scenarios( meanly, working tables or experimental setups).
After a prospective numerical work, the proposed nanostructured grating is finally introduced in the HTL layer( see Fig. 2) composed of ordered stripes with a certain width in x-axis and a length exceeding the unit cell size along y-axis to simulate an infinite bar. Thus, the main geometric parameters of this structure are the height( h) and width( w) of the grating, which are optimized to maximize the absorption of the active layer at the dominant