RESUMEN
The solar energy market is predicted to be shared between Si solar cells and third-generation photovoltaics in the future. Perovskite solar cells (PSCs) show the greatest potential to capture a share there as a single junction or in tandem with silicon. Researchers worldwide are looking to optimize the composition of the perovskite film to achieve an optimal bandgap, performance, and stability. Traditional perovskites have a mixture of formamidinium and methyl ammonium as the A-site cation in their ABX3 structure. However, in recent times, the use of cesium and rubidium has become popular for making highly efficient PSCs. A thorough analysis of the performance and stability of double-, triple-, and quadruple-cation PSCs under different environmental conditions was performed in this study. The performance of the device and the films was analyzed by electrical measurements (J-V, dark J-V, EQE), scanning electron microscopy, atomic force microscopy, photoluminescence, and X-ray diffraction. The quadruple-cation device with the formula Cs0.07Rb0.03FA0.77MA0.13PbI2.8Br0.2 showed the highest power conversion efficiency (PCE) of 21.7%. However, this device had the least stability under all conditions. The triple-cation device with the formula Cs0.1FA0.6MA0.3PbI2.8Br0.2, with a slightly lower PCE (21.2%), was considerably more stable, resulting in about 30% more energy harvested than that using the other two devices during their life cycle.
RESUMEN
Lead (Pb) halide perovskite solar cells (PSCs) exhibit impressive power conversion efficiencies close to those of their silicon counterparts. However, they suffer from moisture instability and Pb safety concerns. Previous studies have endeavoured to address these issues independently, yielding minimal advancements. Here, a general nanoencapsulation platform using natural polyphenols is reported for Pb-halide PSCs that simultaneously addresses both challenges. The polyphenol-based encapsulant is solution-processable, inexpensive (≈1.6 USD m-2), and requires only 5 min for the entire process, highlighting its potential scalability. The encapsulated devices with a power conversion efficiency of 20.7% retained up to 80% of their peak performance for 2000 h and up to 70% for 7000 h. Under simulated rainfall conditions, the encapsulant rich in catechol groups captures the Pb ions released from the degraded perovskites via coordination, keeping the Pb levels within the safe drinking water threshold of 15 ppb.
RESUMEN
Perovskite Solar Cells (PSCs) are the most promising candidates for low-cost and high-efficiency devices in the future photovoltaic market. PSCs are also used as the top cell in tandem devices with silicon bottom cells. However, research in PSCs is still at an early stage while racing towards a promising future. Along with experimental research, numerous simulation studies are conducted with PSCs aiming to analyze new materials and optimize their performance. Here, a wavelength-dependent model is implemented to account for the reflected part of irradiance from the cells, which is ignored in most SCAPS-1D based PSC simulated models. This model optimizes the MgF2 anti-reflective coating in SCAPS-1D simulation to allow maximum photons to pass inside the device. A simple structured PSC (MgF2/Glass/ITO/ZnO/CH3NH3PbI3/Spiro-OMeTAD/Au) is simulated and optimized optically as well as electrically with this model's modified spectrum. The device was optimized for layer thickness, defects, and doping. Moreover, the effects of temperature and device resistances are discussed. The optimized device yields 21.62% power conversion efficiency, which can be further improved to reach over 25% through better processing schemes. Finally, the optimized device was compared with other devices having different ETL/absorber/HTL combinations and the pathway to achieving higher efficiencies was discussed. This article aims at improving the credibility of simulated devices by incorporating top surface reflection with electrical optimization.