Anchored Ligands Facilitate Efficient B-Site Doping in Metal Halide Perovskites

Abstract

Metal halide perovskites exhibit outstanding optoelectronic properties: superior charge carrier mobilities, low densities of deep trap states, high photoluminescence quantum yield, and wide color tunability. The introduction of dopant ions provides pathways to manipulate the electronic and chemical features of perovskites. In metal halide perovskites ABX3, where A is a monovalent cation (e.g., methylammonium (MA+), Cs+), B is the divalent metal ion(s) (e.g., Pb2+, Sn2+), and X is the halide group (e.g., Cl–, Br–, or I–), the isovalent exchange of A- and X-site ions has been widely accomplished; in contrast, strategies to exchange B-site cations are underexamined. The activation energies for vacancy-mediated diffusion of B-site cations are much higher than those for A- and X-sites, leading to slow doping processes and low doping ratios. Herein we demonstrate a new method that exchanges B-site cations in perovskites. We design a series of metal carboxylate solutions that anchor on the perovskite surface, allowing fast and efficient doping of B-sites with both homovalent and heterovalent cations (e.g., Sn2+, Zn2+, Bi3+) at room temperature. The doping process in the reduced-dimensional perovskites is complete within 1 min, whereas a similar reaction only leads to the surface attachment of dopant ions in three-dimensional structures. We offer a model based on ammonium extraction and surface ion-pair substitution.

Lowering the Operating Temperature of Perovskite Catalysts for N2O Decomposition through Control of Preparation Methods

“…The high phase purity, high oxygen mobility and high surface area of the PBC SAS catalyst suggest that this material could be applied to a number of systems, such as photovoltaic systems, including solar cells in addition to suitable catalytic reactions. [35][36][37][38][39][40] When compared to relevant literature examples (Table 1), the PBC SAS outperform that of Kumar et al with a T50 of 442 °C and a decomposition rate of 1.2 mol h -1 kg -1 using a Pr0.2Ba0.8MnO3 catalyst, 55 whereas the PBC SAS catalyst tested here have a T50 of 410 °C and a decomposition rate of 32 mol h -1 kg -1 at 450 °C.…”

“…10,22,[27][28][29][30] There has been a significant effort to produce perovskites with high surface area. [31][32][33][34] Interest in the preparation and use of perovskites has increased significantly in recent years due to the use of perovskites as solar cells, [35][36][37][38][39][40] with perovskites now showing comparable results to commercial solar cells. 41 Perovskites are also known for their oxygen mobility, ease of oxygen vacancy formation and oxygen storage capacity, with these factors contributing greatly to their high catalytic activity for N2O decomposition.…”

Recent Advances in Enhancing and Enriching the Optical Properties of Cl‐Based CsPbX3 Nanocrystals

“…Because the activation energy of Pb 2+ ion migration is higher than that of Cs + and X − ions, the exchange rate of Pb 2+ by other cations is severely curtailed relative to the anion exchange in CsPbX 3 NCs. [ 82 ] Cation doping in CsPbCl 3 NCs is also affected by the activation energy of V Cl diffusion because the movement of cations within the perovskite is driven principally by V Cl migration. [ 82 ] Using a novel halide exchange‐driven cation exchange method (HEDCE), the doped concentration of Mn 2+ ions could reach the maximum atomic percentage of 37.73%.…”

A review on advances in doping with alkali metals in halide perovskite materials

“…Only a small amount of dopants can modify the required characteristics of halide perovskites to the required level without introducing deep energy levels. In addition, doping elements usually do not give rise to the quenched emission due to the surface defect states as reported in conventional II-VI, III-V, and IV-VI inorganic semiconductors [23,24]. Therefore, the strategy to dope heteroatoms into the perovskite structure increases the ability to optimize the structural parameters and efficiency.…”