scholarly journals Strain in Metal Halide Perovskites: The Critical Role of A-Site Cation

2021 ◽  
Author(s):  
Yongtao Liu ◽  
Bobby G. Sumpter ◽  
Jong K. Keum ◽  
Bin Hu ◽  
Mahshid Ahmadi ◽  
...  
Keyword(s):  
Critical Role ◽  
Metal Halide ◽  
Halide Perovskites ◽  
A Site

scholarly journals Role of Polar Phonons in the Photo Excited State of Metal Halide Perovskites

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Menno Bokdam ◽  
Tobias Sander ◽  
Alessandro Stroppa ◽  
Silvia Picozzi ◽  
D. D. Sarma ◽  
...  
Keyword(s):  
Excited State ◽  
Metal Halide ◽  
Halide Perovskites

A‐Site Cation Engineering of Metal Halide Perovskites: Version 3.0 of Efficient Tin‐Based Lead‐Free Perovskite Solar Cells

2020 ◽  
Vol 30 (34) ◽  
pp. 2000794 ◽  
Author(s):  
Weiyin Gao ◽  
Changshun Chen ◽  
Chenxin Ran ◽  
Hao Zheng ◽  
He Dong ◽  
...  
Keyword(s):  
Solar Cells ◽  
Perovskite Solar Cells ◽  
Metal Halide ◽  
Lead Free ◽  
Halide Perovskites ◽  
A Site

Phosphorylation of Ser136 is critical for potent bone sialoprotein-mediated nucleation of hydroxyapatite crystals

2010 ◽  
Vol 428 (3) ◽  
pp. 385-395 ◽  
Author(s):  
Gurpreet S. Baht ◽  
Jason O'Young ◽  
Antonia Borovina ◽  
Hong Chen ◽  
Coralee E. Tye ◽  
...  
Keyword(s):  
Critical Role ◽  
Bone Sialoprotein ◽  
Site Directed Mutagenesis ◽  
Crystal Face ◽  
Mineralized Tissues ◽  
Dynamics Simulations ◽  
A Site ◽  
Functional Analyses ◽  
Kinase Ck2

Acidic phosphoproteins of mineralized tissues such as bone and dentin are believed to play important roles in HA (hydroxyapatite) nucleation and growth. BSP (bone sialoprotein) is the most potent known nucleator of HA, an activity that is thought to be dependent on phosphorylation of the protein. The present study identifies the role phosphate groups play in mineral formation. Recombinant BSP and peptides corresponding to residues 1–100 and 133–205 of the rat sequence were phosphorylated with CK2 (protein kinase CK2). Phosphorylation increased the nucleating activity of BSP and BSP-(133–205), but not BSP-(1–100). MS analysis revealed that the major site phosphorylated within BSP-(133–205) was Ser136, a site adjacent to the series of contiguous glutamate residues previously implicated in HA nucleation. The critical role of phosphorylated Ser136 in HA nucleation was confirmed by site-directed mutagenesis and functional analyses. Furthermore, peptides corresponding to the 133–148 sequence of rat BSP were synthesized with or without a phosphate group on Ser136. As expected, the phosphopeptide was a more potent nucleator. The mechanism of nucleation was investigated using molecular-dynamics simulations analysing BSP-(133–148) interacting with the {100} crystal face of HA. Both phosphorylated and non-phosphorylated sequences adsorbed to HA in extended conformations with alternating residues in contact with and facing away from the crystal face. However, this alternating-residue pattern was more pronounced when Ser136 was phosphorylated. These studies demonstrate a critical role for Ser136 phosphorylation in BSP-mediated HA nucleation and identify a unique mode of interaction between the nucleating site of the protein and the {100} face of HA.

Nonlinear photocarrier dynamics and the role of shallow traps in mixed-halide mixed-cation hybrid perovskites

2021 ◽  
Author(s):  
David Alberto Valverde-Chávez ◽  
Esteban Rojas-Gatjens ◽  
Jacob Williamson ◽  
Sarthak Jariwala ◽  
Yangwei Shi ◽  
...  
Keyword(s):  
Surface Passivation ◽  
Metal Halide ◽  
Carrier Trapping ◽  
Mixed Cation ◽  
Halide Perovskites ◽  
Shallow Traps ◽  
Recombination Dynamics

We examine the role of surface passivation on carrier trapping and nonlinear recombination dynamics in hybrid metal-halide perovskites by means of excitation correlation photoluminescence (ECPL) spectroscopy. We find that carrier...

scholarly journals Deciphering the effect of traps on electronic charge transport properties of methylammonium lead tribromide perovskite

2020 ◽  
Vol 6 (37) ◽  
pp. eabb6393
Author(s):  
Artem Musiienko ◽  
Jindřich Pipek ◽  
Petr Praus ◽  
Mykola Brynza ◽  
Eduard Belas ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Charge Transport ◽  
Transport Properties ◽  
Critical Role ◽  
Charge Carriers ◽  
Electronic Charge ◽  
Free Charge ◽  
Optoelectronic Materials ◽  
Halide Perovskites

Halide perovskites have undergone remarkable developments as highly efficient optoelectronic materials for a variety of applications. Several studies indicated the critical role of defects on the performance of perovskite devices. However, the parameters of defects and their interplay with free charge carriers remain unclear. In this study, we explored the dynamics of free holes in methylammonium lead tribromide (MAPbBr3) single crystals using the time-of-flight (ToF) current spectroscopy. By combining ToF spectroscopy and Monte Carlo simulation, three energy states were detected in the bandgap of MAPbBr3. In addition, we found the trapping and detrapping rates of free holes ranging from a few microseconds to hundreds of microseconds. Contrary to previous studies, we revealed a strong detrapping activity of traps. We showed that these traps substantially affect the transport properties of MAPbBr3, including mobility and mobility-lifetime product. Our results provide an insight on charge transport properties of perovskite semiconductors.

scholarly journals The Role of Grain Boundaries on Ionic Defect Migration in Metal Halide Perovskites

2020 ◽  
Vol 10 (20) ◽  
pp. 1903735 ◽  
Author(s):  
Nga Phung ◽  
Amran Al‐Ashouri ◽  
Simone Meloni ◽  
Alessandro Mattoni ◽  
Steve Albrecht ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Metal Halide ◽  
Defect Migration ◽  
Halide Perovskites ◽  
Ionic Defect

scholarly journals Critical Role of Cys168 in Noggin Protein's Biological Function

2005 ◽  
Vol 37 (3) ◽  
pp. 181-185
Author(s):  
Wei-Dong Liu ◽  
Xiang-Ling Feng ◽  
Cai-Ping Ren ◽  
Jian-Ling Shi ◽  
Xu-Yu Yang ◽  
...  
Keyword(s):  
Biological Activities ◽  
Critical Role ◽  
Ectopic Expression ◽  
Disulfide Bridge ◽  
Site Directed Mutagenesis ◽  
Morphogenetic Protein ◽  
Neural Cell Adhesion ◽  
A Site ◽  
The Relationship

Abstract Previous that noggin exerts its neural inducing effect by binding and antagonizing bone morphogenetic protein 4 (BMP4). In order to further clarify the relationship between the structure and the function of noggin, and elucidate the possible mechanism responsible for noggin-BMP4 interaction, we generated three noggin mutants, C168S, C174S and C197S, by using a site-directed mutagenesis method. Ectopic expression of wild-type (WT) noggin, C174S or C197S, in Xenopus animal caps (ACs) by mRNA injection converted the explants (prospective ectoderm) into neural tissue, as indicated by the neural-like morphology and expression of the neural cell adhesion molecule (NCAM) in the ACs. In contrast, ACs expressing C168S suffered an epidermal fate similar to the control caps. Similarly, among the three mutants, only C168S lost the dorsalizing function. These studies highlight the critical role played by Cys168 in noggin's biological activities. It probably participates in the formation of an intermolecular disulfide bridge.

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