The stability of hybrid lead iodine perovskite in a humid environment has been a major obstacle to developing long-term photovoltaic devices. However, understanding the detailed degradation mechanism of lead iodine perovskite in moisture is still challenging. Herein, using first-principles calculations, we show that embedded water molecules will facilitate the decomposition of lead iodine perovskite. Alloying FAPbI and CsPbI to form mixed-cation lead iodine perovskites not only can optimize the tolerance factor to obtain better phase stability, but also can improve the moisture stability of them. With the accumulation of water molecules in the perovskite lattice, the optical absorption spectra show a blue-shift and decreased intensity, and the moisture stabilities of lead iodine perovskites are further lowered. The iodine vacancy in lead iodine perovskites can facilitate the water molecule migration and thus is a disadvantage in improving the moisture stability of them, which should be minimized during perovskite growth. These findings provide new insight in understanding the poor moisture stability of lead iodine perovskites, which should be helpful for the future design and optimization of stable perovskite solar cells.

All-inorganic perovskites have gained considerable significance. Despite their superior thermal robustness, poor phase stability has rendered inorganic perovskites adverse. Herein, on the basis of first-principles calculations, we find that the incorporation of rubidium (Rb) and potassium (K) in an appropriate ratio will stabilize CsPbI2Br perovskites considerably, in which the cooperative interactions between Rb/K, I and Br play an important role. Besides, it is verified that 2D orthorhombic CsPbI3 with a thickness of ∼1 nm exhibits outstanding stability, even exceeding the non-perovskite, yellow structure and has a suitable band gap for solar cell applications.

Liver cancer is one of the most common cancers in the world. Of all types of liver cancer, hepatocellular carcinoma (HCC) is known to be the most frequent primary liver malignancy and has seriously compromised the health status of the general population. Locoregional thermal ablation techniques such as radiofrequency and microwave ablation, have attracted attention in clinical practice as an alternative strategy for HCC treatment. However, their aggressive thermal effect may cause undesirable complications such as hepatic decompensation, hemorrhage, bile duct injury, extrahepatic organ injuries, and skin burn . In recent years, photodynamic therapy (PDT), a gentle locoregional treatment, has attracted attention in ablation therapy for patients with superficial or luminal tumors as an alternative treatment strategy. However, some inherent defects and extrinsic factors of PDT have limited its use in clinical practice for deep-seated HCC. In this contribution, the aim is to summarize the current status and challenges of PDT in HCC treatment and provide potential strategies to overcome these deficiencies in further clinical translational practice.