Design Principles of Large Cation Incorporation in Halide Perovskites

Perovskites have stood out as excellent photoactive materials with high efficiencies and stabilities, achieved via cation mixing techniques. Overcoming challenges to the stabilization of Perovskite solar cells calls for the development of design principles of large cation incorporation in halide perovskite to accelerate the discovery of optimal stable compositions. Large fluorinated organic cations incorporation is an attractive method for enhancing the intrinsic stability of halide perovskites due to their high dipole moment and moisture-resistant nature. However, a fluorinated cation has a larger ionic size than its non-fluorinated counterpart, falling within the upper boundary of the mixed-cation incorporation. Here, we report on the intrinsic stability of mixed Methylammonium (MA) lead halides at different concentrations of large cation incorporation, namely, ehtylammonium (EA; [CH3CH2NH3]+) and 2-fluoroethylammonium (FEA; [CH2FCH2NH3]+). Density functional theory (DFT) calculations of the enthalpy of the mixing and analysis of the perovskite structural features enable us to narrow down the compositional search domain for EA and FEA cations around concentrations that preserve the perovskite structure while pointing towards the maximal stability. This work paves the way to developing design principles of a large cation mixture guided by data analysis of DFT data. Finally, we present the automated search of the minimum enthalpy of mixing by implementing Bayesian optimization over the compositional search domain. We introduce and validate an automated workflow designed to accelerate the compositional search, enabling researchers to cut down the computational expense and bias to search for optimal compositions.

Stabilization Effect of Intrinsically Disordered Regions on Multidomain Proteins: The Case of the Methyl-CpG Protein 2, MeCP2

Intrinsic disorder plays an important functional role in proteins. Disordered regions are linked to posttranslational modifications, conformational switching, extra/intracellular trafficking, and allosteric control, among other phenomena. Disorder provides proteins with enhanced plasticity, resulting in a dynamic protein conformational/functional landscape, with well-structured and disordered regions displaying reciprocal, interdependent features. Although lacking well-defined conformation, disordered regions may affect the intrinsic stability and functional properties of ordered regions. MeCP2, methyl-CpG binding protein 2, is a multifunctional transcriptional regulator associated with neuronal development and maturation. MeCP2 multidomain structure makes it a prototype for multidomain, multifunctional, intrinsically disordered proteins (IDP). The methyl-binding domain (MBD) is one of the key domains in MeCP2, responsible for DNA recognition. It has been reported previously that the two disordered domains flanking MBD, the N-terminal domain (NTD) and the intervening domain (ID), increase the intrinsic stability of MBD against thermal denaturation. In order to prove unequivocally this stabilization effect, ruling out any artifactual result from monitoring the unfolding MBD with a local fluorescence probe (the single tryptophan in MBD) or from driving the protein unfolding by temperature, we have studied the MBD stability by differential scanning calorimetry (reporting on the global unfolding process) and chemical denaturation (altering intramolecular interactions by a different mechanism compared to thermal denaturation).

E.L.S.A: E. coli Learning Suboptimal Acclimatization

Low intrinsic stability has marred the production of psychrophilic proteins in commonly used mesophilic systems. This may lead to a lopsided bias towards the expression of the few psychrophilic proteins which can manage a stable structure at those temperatures. Of the two possible approaches to help counterpoise the expression in favour of most psychrophilic proteins, the approach we have taken is to develop a new psychrophilic host. Rather than characterizing novel strains, we plan on converting a highly characterized system in synthetic biology, E.coli, by introducing genes that confer cold-tolerance to it thereby reducing dependency on regular mesophilic hosts and possibly making it the model system for cold temperature-based systems.

A Review on Stability of Inorganic Metal Halide Perovskites: Challenge and Opportunity for Stable Solar Cells

Inorganic perovskite based solar cells (PSCs) have been receiving unprecedented attention worldwide in the past several years due to their higher intrinsic stability towards high temperature and high theoretical power...

Low resistant and stable lithium-garnet electrolyte interface enabled by a multifunctional anode additive for solid-state lithium batteries

Solid-state batteries (SSBs) have attracted considerable attention due to the high intrinsic stability and theoretical energy density. As the core part, garnet electrolyte has been extensively investigated due to high...

Pushing Commercialization of Perovskite Solar Cells by Improving Their Intrinsic Stability

Despite the rapid progress in power conversion efficiency (PCE) from 3.8% to 25.5% with ten years of effort, the real outdoor applications of perovskite solar cells (PSCs) are still significantly...