Perovskite solar cells have made significant strides in recent years. However, there are still challenges in terms of photoelectric conversion efficiency and long-term stability associated with perovskite solar cells. The presence of defects in perovskite materials is one of the important influencing factors leading to subpar film quality. Adopting additives to passivate defects within perovskite materials is an effective approach. Therefore, we first discuss the types of defects that occur in perovskite materials and the mechanisms of their effect on performance. Then, several types of additives used in perovskite solar cells are discussed, including ionic compounds, organic molecules, polymers, etc. This review provides guidance for the future development of more sustainable and effective additives to improve the performance of solar cells.

A YN₂ monolayer can realize multiple topological phases, determined based on the magnetization direction. In particular, the in-plane QAHE can be realized in a d⁰ ferromagnet.

Electrides in two-dimensional (2D) scale, especially those capture inherent magnetism and low work functions, have shown great application prospects in nanoscale spintronic devices and electronic emitters. However, searching ideal 2D magnetic electrides are still great challenges. Herein, based on first-principles calculations, we demonstrate 2D CaCl is strippable from the heterostructure of experimental CaCl/graphene and reveal the freestanding 2D CaCl is a novel electride phase. In this material, sufficient electrons are trapped in the lattice voids and act as anions within the positive crystalline framework, following the electide form of [CaCl]⁺●e^-. Due to the unique electron behaviours of electrides, 2D [CaCl]⁺●e^- possesses a series of interesting physical phenomena. 1) The electride [CaCl]⁺●e^- exhibits room-temperature ferromagnetism, the magnetic moment originates from the excess electrons with s-like orbital feature rather than atomic orbital ones, which is drastically different with traditional 2D ferromagnets. 2) The electride [CaCl]⁺●e^- shows magnetic metal characteristics, and by doping halogen elements can exectively regulate the electronic structure. 3) Most remarkably, FM electride [CaCl]⁺●e^- shows an extremely low work function (2.65 eV). This value is the lowest among electrides in 2D materials reported so far. Besides, the dimension of excess electron can be effectively regulated by controlling temperature. This work provides an excellent candidate to investigate 2D magnetic electrides and associated applications.

The effect of Pb in La₃Te_4−x Pb _x on the thermoelectric properties in the temperature range 300–1100 K was studied on samples synthesized by the melting, ball milling and hot-pressing method. The samples crystallize in the Th₃P₄structure. A small amount of Pb substitution for Te in La₃Te₄ reduced the electrical conductivity, but the impurity phase introduced by more Pb significantly enhanced the electrical conductivity. The electrical conductivity of the La₃Te_3.6Pb_0.4 sample reached 2.06 × 10⁵ S m⁻¹ at room temperature. The expansion of crystal lattice confirmed from x-ray diffraction patterns and the slight reduction in electrical conductivity all verify the fact that Pb substitutes a Te site when x is small. The Seebeck coefficient increases linearly with temperature for all samples. While the thermal conductivity varies slightly with temperature, the lattice thermal conductivity approaches the minimum value at high temperatures. For La₃Te_3.7Pb_0.3, a power factor of 1.4 × 10⁻³ W m⁻¹ K⁻² at 1100 K was achieved with a thermal conductivity of 1.86 W m⁻¹ K⁻¹, giving a maximum figure-of-merit ZT ≈ 0.8 at 1100 K.