## 3 Results and Discussion
### Optical Performances  
The absorption value of PSC is affected by variations in PC radius and lattice constant in the structure. Thus, the contribution of each layer on absorption performance is observed. The absorption spectra of each layer are shown in Figure 2. It can be seen that the perovskite layer (MAPbI\({}_{3}\)) contributes the most absorption compared to other layers. This indicates that the function of the perovskite layer as an active layer/absorber works well. This layer absorbed more than 80% of the incident light at 300-630 nm, with the maximum absorption reaching 92% at 409-429 nm of wavelength and dropping at 630-1000 nm. Meanwhile, in the FTO, TiO\({}_{2}\), Spiro-OMeTAD, and Au layers, it is seen that photons are absorbed much less than in the perovskite layers. This indicates that only a tiny fraction of the incident light photons is trapped in these layers. Most of the photons are transmitted to the perovskite layer. Figure 3 shows the absorption spectra for all PC radius variations and the lattice constant obtained from the FDTD simulations. It shows the absorption as a wavelength function in the 300-1000 nm range and shows a significant change in absorption for each wavelength point. From 300 nm to 800 nm, the absorption increases as the radius of the nanodisk is higher. It occurs because the more the radius increases, the more that the photons from incident light can be in slow photon mode. On the other hand, the absorption decreases as the lattice constant increases. This also happens because the more lattice constant increase (more space at the structure), the fewer photons get into slow photon mode. The design shows that the structure absorbs over 90% of the incident light. The result proves that the nanodisk PC increases the absorption of the PSC. The optimum performance is achieved at a 225 nm radius of the nanodisk PC, reaching 94% absorption of the incident light, meaning that there is an enhancement of absorption when the flat PSC only reaches 85% at the same wavelength. Figure 4 compares PSC with PC and flat PSC in absorption performance. It shows that there is absorption enhancement in PSC with PC. This enhancement can lead PSC to better electrical performance. Figure 1: Simulated structures of PSC with photonic crystals on FDTD simulations. Figure 3: The absorption spectrum profile of PSC for **(a)** different radius of photonic crystals and **(b)** enlarged absorption spectrum at 300 nm to 850 nm, and **(c)** different lattice constant and **(d)** its enlarged absorption spectrum at 300 nm to 850 nm. Figure 2: The absorption spectra for every layer in this structure. Figure 5 shows the distribution profile of electromagnetic wave fields for flat PSC and nanodisk PC-based PSC on every peak of absorption spectra that shown. The profile is analyzed from every peak on absorption spectra, including 390 nm, 642 nm, 759 nm, and 900 nm of optimum design, 225 nm of radius, and 500 nm of lattice constant, as shown in Figure 5. The deep blue color indicates the low-intensity electromagnetic field, while the red color indicates the high-intensity electromagnetic field based on the number above the scale. It is shown in Figure 5 that the electromagnetic field is more likely to be trapped outside the absorber layer for lower wavelength until the wavelength is increased. For a longer wavelength, it starts to enter the absorber layer. From Figure 5, we can also see that the PC-based PSC has a higher electromagnetic field intensity. Moreover, the performance of the PSC is evaluated by its \(J_{sc}\), and it is shown in Table 2. The trends of \(J_{sc}\) are linear to the result of absorption spectra. The highest \(J_{sc}\) that reached by the optimum design (\(r=225\) nm, \(a=500\) nm) in this work is 26.473 mA/cm\({}^{2}\). This result also proves that when the absorber material used is MAPbI\({}_{3}\); the performance is increased compared to the work by [PERSON] et al. [16].