Exploring stable and efficient lead‐free perovskite solar cells (PSCs) is critical to solving the environmental concerns caused by lead. Recently, tin halide perovskites (THPs) have become a promising candidate due to its low toxicity and similar electronic configuration to lead counterparts. Currently, the power conversion efficiency of tin‐based PSCs (TPSCs) has been pushed over 14%. However, there is still a considerable gap compared to lead PSCs due to the non‐negligible open‐circuit voltage loss (Vloss). Therefore, understanding the origins and regulation strategies of Vloss for TPSCs is of great importance. Herein, the nature of THPs is first reviewed from the crystal structure, electronic structure, and phase transition. Subsequently, the origins and determinants of Vloss are discussed in TPSCs. Besides the intrinsic low bandgap, the bulk recombination of tin perovskite, and the non‐radiative recombination of the associated interfaces induce the Vloss of the TPSCs devices. Then, some recently emerged strategies to suppress the Vloss in TPSCs are introduced. Finally, a perspective on the further suppression of Vloss in TPSCs including purifying the precursor solution, suppressing the oxidation Sn2+, and optimizing the device structure is outlined.

No abstract

No abstract

No abstract

All-solid-state batteries (ASSBs) using an alkali metal anode and a solid-state electrolyte (SE) face several problems due to poor physical and electrical contact. Recent experiments have shown that applying a stack pressure can improve the interface contact and suppress void formation. The mechanical properties of Na metal are different from those of Li metal, leading to differences in the mechanisms of the pressure-dependent interface evolution. Herein, we report a three-dimensional time-dependent model for tracking the evolution of interfaces formed between Na metal and Na-β″-alumina SE. Our results show that Na metal contacts more conformally with the SE, providing a lower interfacial resistance, compared with Li metal, assuming equal resistance due to contamination. The differences due to contact elastoplasticity are larger than the differences in metal creep effects. In fact, we show that increased stack pressure can lead to lower creep because the contact is more conformal at high pressures. Our excellent agreement with recent experiments determines an effective hardness of Na in the Na-SE batteries to be 15 MPa. The results further reveal that the pressure dependence of void suppression is dominated by contact elastoplasticity.