Stable Dynamics Performance and High Efficiency of ABX₃‐Type Super‐Alkali Perovskites First Obtained by Introducing H₅O₂ Cation

Abstract

Developing new ABX3‐type perovskites is very important for expanding the family of perovskites and obtaining excellent light absorbing material. One strategy is replacing A site atoms with super‐alkali atoms for the perovskites, but super‐alkali perovskites with stable dynamics performance and high efficiency have not been found until now. Herein, massive super‐alkalis, such as Li3O, Li2F, H5O2, and so on, are introduced into the cubic CH3NH3PbI3 perovskites, and the perovskites with these super‐alkalis are systematically studied by using ab initio molecular dynamics simulation and density functional theory based first principles calculations. Calculated results indicate that the perovskites with the super‐alkalis including metal atoms show unstable dynamics performance under normal temperature and pressure. On the contrary, the first obtainable super‐alkali perovskites of cubic H5O2MBr3 (M = Ge, Sn, Pb) and H5O2PbI3 show stable dynamics performance. They also show suitable tolerance factors, negative formation energies, tunable direct band gaps, and small effective hole and electron masses. Moreover, the calculated power conversion efficiencies of 23.17% and 22.83% are obtained for the single‐junction solar cells based on the cubic H5O2SnBr3 and H5O2PbBr3 perovskites, respectively.

Exploration of terahertz from time-resolved ultrafast spectroscopy in single-crystal Bi2Se3 topological insulator

“…First, by FFT (fast Fourier transformation) and another by FFD (filtering high frequency component followed by fitting data) [14,17,24,25]. The two distinct theoretical approaches (FFT & FFD) resulted in elucidation of terahertz frequency differing by an order of magnitude which has also been reported for perovskite, such as, two-dimensional lead-free hybrid halide perovskite using super atom anions with tunable electronic properties; stable dynamics performance and high efficiency of ABX3type super-alkali perovskites first obtained by introducing H5O2 cation; tunable electronic structures and high efficiency obtained by introducing super alkali and super halogen into AMX3type perovskites and in Bi2Te3 topological insulator [14,17,[24][25][26][34][35][36][37]. The current article not only substantiates terahertz generation from flakes of bulk single-crystal Bi2Se3, but also points out an important fact that various fitting models may lead to different results.…”

First‐Principles Optimization of Out‐of‐Plane Charge Transport in Dion–Jacobson CsPbI3 Perovskites with π‐Conjugated Aromatic Spacers

“…A running time of 5 ps is carried out in the AIMD simulations, which is enough for the energy and structure of the system to reach equilibrium. [ 31–34 ] It is disclosed that the energy fluctuation and root mean square deviation (RMSD) for (PPDA)Cs n −1 Pb n I 3 n +1 perovskites are smaller, compared to that of (EDA)Cs n −1 Pb n I 3 n +1 perovskites (see Figure S15, Supporting Information), suggesting that π‐conjugated aromatic spacers (i.e., PPDA 2+ ) could improve the stability of DJ CsPbI 3 perovskites.…”

Tetra-indole core as a dual agent: a hole selective layer that passivates defects in perovskite solar cells

“…In addition, the interface properties between the perovskite and HTM plays a trivial role in achieving high reliability in PSCs. [19][20][21][22] The interfacial property is dependent on the HTM layer, mainly due to their appropriate highest occupied molecular orbitals (HOMO) energy level for band alignment. 23 Spiro-OMeTAD is being considered as standard and is widely used HTM in PSCs.…”