How to Stabilize the Current of Efficient Inverted Flexible Perovskite Solar Cells at the Maximum Power Point

Abstract

Inverted flexible perovskite cells (fPSCs) have attracted much attention for their high efficiency and power per weight. Still, the steady–state output is one of the critical factors for their commercialization. In this paper, it is found that the steady–state current of inverted fPSCs based on nickel oxide nanoparticles (n‐NiOx) continuously decreases under light illumination. Conversely, those based on magnetron‐sputtered NiOx (sp‐NiOx) exhibit the opposite result. Based on visualization of ion migration in the photoluminescence (PL) imaging microscopy tests, the discrepancies in the buried surfaces lead to the differences in ion migration in perovskite films, which triggers the temporary instability of the output current of devices during operation. The DFT theoretical calculation and experimental results reveal that NiOx films with different contents of Ni vacancies can modulate the crystallization of the perovskite films on the NiOx surfaces. Tuning the crystallization of the perovskite films is essential to stabilize the output current of fPSCs at a steady state. To demonstrate that, capsaicin is doped into the perovskite solutions to improve the quality of the perovskite buried interface. Finally, the corresponding fPSCs exhibit outstanding efficiency and stability during operation. These results provide valuable scientific guidance for fabricating fPSCs with stable operation under illumination conditions.

One-Stone-for-Two-Birds Method to Improve the SnO2 Layers for High Power-per-Weight Flexible Perovskite Solar Cell Mini-modules

“…Thus, we focused on the effect of PAAm modification on the buried surface of the perovskite films, which is directly affected by the change in chemical state of the SnO 2 film. We adopted a facile technique to exfoliate the perovskite layer from the SnO 2 surface and studied the buried surface in contact with the SnO 2 film surface. − …”

“…As shown in Figure a, the PAAm-modified fPSC shows a stabilized output current, while the control one exhibits a noticeable decline after 200 s of continuous illumination. The increased stabilized output should be attributed to the improved buried interface, where ion migration is prohibited. , …”

“…The increased stabilized output should be attributed to the improved buried interface, where ion migration is prohibited. 39,40 Next, we checked the modified fPSCs' environmental and heat stability. According to the ISOS-D-1 protocol, 50 we placed unencapsulated fPSCs were in ambient air at 30% relative humidity (RH) and 25 °C for 1000 h. As shown in Figure 7b, the PAAm-modified fPSC retains 89.6% of the initial PCE after 1000 h of storage, while the control sample has only 64.6% of its initial PCE.…”