An optimal small amount of water added into methyl ammonium iodide (MAI) solution in isopropyl alcohol (IPA) helps perovskite crystallization and leads to larger grain size from sequential deposition of perovskite films. The concentration of water was varied from 1% to 7% (vol% of IPA) in MAI solution and optical absorption, crystallization, morphology of perovskite films and their photovoltaic performance were studied in perovskite solar cells. 5% by volume was found to lead to preferential crystallization in the (110) plane with grain size about three times that of perovskite films prepared without adding water into the MAI solution. The optimal water concentration of 5% by volume in the MAI solution led to average perovskite grain size of ∼600 nm and solar cell efficiency of 12.42% at forward scan with a rate of 0.5 V s⁻¹. Device performance decreases after increasing water concentration beyond 5% in the MAI solution due to formation of the PbI₂ phase. Transient photocurrent and photovoltage measurements show the shortest charge transport time at 0.99 μs and the longest charge carrier life time at 13.6 μs for perovskite films prepared from 5% water in MAI solution, which improved perovskite solar cell efficiency from 9.04% to 12.42%.

Fundamental shifts in the structure and generation profile of electrical grids are occurring amidst increased demand for resilience. These two simultaneous trends create the need for new planning and operational practices for modern grids that account for the compounding uncertainties inherent in both resilience assessment and increasing contribution of variable inverter-based renewable energy sources. This work reviews the research work addressing the changing generation profile, state-of-the-art practices to address resilience, and research works at the intersection of these two topics in regards to electrical grids. The contribution of this work is to highlight the ongoing research in power system resilience and integration of variable inverter-based renewable energy sources in electrical grids, and to identify areas of current and further study at this intersection. Areas of research identified at this intersection include cyber-physical analysis of solar, wind, and distributed energy resources, microgrids, network evolution and observability, substation automation and self-healing, and probabilistic planning and operation methods.

Distributed energy resources (DERs) are transforming the operation and planning of both distribution and transmission grids. Stability impacts from the increasing generation contribution of DERs have been widely recognized in distribution systems and are emerging in transmission systems. There is a need for the development of transmission hosting capacity studies of DERs so utilities will be able to predict and prevent instabilities, reductions in reliability on the electrical grid, and create planning methodologies that enable the continued growth of DERs. This paper evaluates the impact of different modeling considerations for assessing hosting capacity of DERs in transmission systems through analysis on a 2,000-bus synthetic grid test system. The modeling considerations include transient and steady state contingencies, use of dynamic load and DER models with voltage support control, dynamic load composition, and seasonal and loading scenarios. The results demonstrate that transient stability evaluations are more limiting than steady state analysis, the use of voltage support control in DERs can increase hosting capacity in the system, and large variations in hosting capacity can be found when assessing between seasonal variations. From comparing system factors the amount of wind generation in the system was a critical factor for hosting capacity in this study.