Auger recombination is a pivotal process for semiconductor nanocrystals (NCs), significantly affecting charge carrier generation and collection in optoelectronic devices. This process depends mainly on the NCs' electronic structures. In our study, we investigated Auger recombination dynamics in manganese (Mn)-doped CsPbI NCs using transient absorption (TA) spectroscopy combined with theoretical and experimental structural characterization.
View Article and Find Full Text PDFPhys Chem Chem Phys
August 2023
Janus nanotubes originating from rolling up asymmetric dichalcogenide monolayers have shown unique properties compared to their 2D and 3D counterparts. Most of the work on Janus nanotubes is focused on single-wall (SW) tubes. In this work, we have investigated the structural and electronic properties of double wall (DW) MoSTe nanotubes using Density Functional Theory (DFT).
View Article and Find Full Text PDFHot carrier (HC) cooling accounts for the significant energy loss in lead halide perovskite (LHP) solar cells. Here, we study HC relaxation dynamics in Mn-doped LHP CsPbI nanocrystals (NCs), combining transient absorption spectroscopy and density functional theory (DFT) calculations. We demonstrate that Mn doping (1) enlarges the longitudinal optical (LO)-acoustic phonon bandgap, (2) enhances the electron-LO phonon coupling strength, and (3) adds HC relaxation pathways Mn orbitals within the bands.
View Article and Find Full Text PDFThe exploration for thermoelectric thin films of complex oxides such as SrTiO-based oxides is driven by the need for miniaturized harvesting devices for powering the Internet of Things (IoT). However, there is still not a clear consensus in the literature for the underlying influence of film thickness on thermoelectric properties. Here, we report the fabrication of epitaxial thin films of 6% Nb-doped SrTiO on (001) (LaAlO)(SrAlTaO) (LSAT) single crystal using pulsed laser deposition (PLD) where the film thickness was varied from 2 nm to 68 nm.
View Article and Find Full Text PDFThe use of ferroelectric materials for light-harvesting applications is a possible solution for increasing the efficiency of solar cells and photoelectrocatalytic devices. In this work, we establish a fully autonomous computational workflow to identify light-harvesting materials for water splitting devices based on properties such as stability, size of the band gap, position of the band edges, and ferroelectricity. We have applied this workflow to investigate the Ruddlesden-Popper perovskite class and have identified four new compositions, which show a theoretical efficiency above 5%.
View Article and Find Full Text PDFThe physical origin of sub-band gap photoluminescence in Ruddlesden-Poppers two-dimensional (2D) lead halide perovskites (LHPs) is still under debate. In this paper, we studied the photoluminescence features from two different facets of 2D LHP single crystals: the in-plane facet (IF) containing the 2D inorganic layers and the facet perpendicular to the 2D layers (PF). At the IF, the free carriers (FCs) dominate due to the weak electron-phonon coupling in a symmetric lattice.
View Article and Find Full Text PDFTransition-metal ion doping has been demonstrated to be effective for tuning the photoluminescence properties of perovskite quantum dots (QDs). However, it would inevitably introduce defects in the lattice. As the Mn concentration increases, the Mn dopant photoluminescence quantum yield (PLQY) first increases and then decreases.
View Article and Find Full Text PDFACS Appl Mater Interfaces
March 2018
The electromagnetic properties at the interface of heterostructure are sensitive to the interfacial crystal structure and external field. For example, the two-dimensional magnetic states at the interface of LaAlO/SrTiO are discovered and can further be controlled by electric field. Here, we study two types of heterostructures, TiO/PbTiO and SrTiO/PbTiO, using first-principle electronic structure calculations.
View Article and Find Full Text PDFBoosting power density is one of the primary challenges that current lithium ion batteries face. Alloying anodes that possess suitable potential windows stand at the forefront in pursuing ultrafast and highly reversible lithium storage to achieve high power/energy lithium ion batteries. Herein, ultrafast lithium storage in Sn-based nanocomposite anodes is demonstrated, which is boosted by pseudocapacitance benefitting from a high fraction of highly interconnected interfaces of Fe/Sn/Li O.
View Article and Find Full Text PDF