We elucidate the mechanism of a newly observed photovoltaic effect which occurs in ferroelectrics with periodic domain structures. Under sufficiently strong illumination, domain walls function as nanoscale generators of the photovoltaic current. The steps in the electrostatic potential function to accumulate electrons and holes on opposite sides of the walls while locally reducing the concentration of the oppositely charged carriers. As a result, the recombination rate adjacent to the walls is reduced, leading to a net diffusion current. In open circuit, photovoltages for periodically ordered domain walls are additive and voltages much larger than the band gap can be generated. The internal quantum efficiency for individual domain walls can be surprisingly high, approaching 10% for above band-gap photons. Although we have found the effect in BiFeO(3) films, it should occur in any system with a similar periodic potential.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1103/PhysRevLett.107.126805 | DOI Listing |
Environ Toxicol Chem
January 2025
School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, PR China.
In silico methods are increasingly important in predicting the ecotoxicity of engineered nanomaterials (ENMs), encompassing both individual and mixture toxicity predictions. It is widely recognized that ENMs trigger oxidative stress effects by generating intracellular reactive oxygen species (ROS), serving as a key mechanism in their cytotoxicity studies. However, existing in silico methods still face significant challenges in predicting the oxidative stress effects induced by ENMs.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Daegyung Technology Application Division, Korea Institute of Industrial Technology, Daegu-si 42994, Republic of Korea.
In semiconductor inspection equipment, a chuck used to hold a wafer is equipped with a cooling or heating system for temperature uniformity across the surface of the wafer. Surface temperature uniformity is important for increasing semiconductor inspection speed. Triply periodic minimal surfaces (TPMSs) are proposed to enhance temperature uniformity.
View Article and Find Full Text PDFSmall Methods
January 2025
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, TN 37830, USA.
Understanding ferroelectric domain wall dynamics at the nanoscale across a broad range of timescales requires measuring domain wall position under different applied electric fields. The success of piezoresponse force microscopy (PFM) as a tool to apply local electric fields at different positions and imaging their changing position, together with the information obtained from associated switching spectroscopies has fueled numerous studies of the dynamics of ferroelectric domains to determine the impact of intrinsic parameters such as crystalline order, defects and pinning centers, as well as boundary conditions such as environment. However, the investigation of sub-coercive reversible domain wall vibrational modes requires the development of new tools that enable visualizing domain wall motion under varying applied fields with high temporal and spatial resolution while also accounting for spurious electrostatic effects.
View Article and Find Full Text PDFPlanta
January 2025
Institute of Plant Biology, National Taiwan University, Taipei, Taiwan.
PME12-mutated plants displayed altered stomatal characteristics and susceptibility to ABA-induced closure. Despite changes in PME activity, the mutant exhibited enhanced thermotolerance. These findings suggest a complex interplay between pectin methylesterification, ABA response, and stomatal function, contributing to plant adaptation to heat stress.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305.
A central paradigm of nonequilibrium physics concerns the dynamics of heterogeneity and disorder, impacting processes ranging from the behavior of glasses to the emergent functionality of active matter. Understanding these complex mesoscopic systems requires probing the microscopic trajectories associated with irreversible processes, the role of fluctuations and entropy growth, and the timescales on which nonequilibrium responses are ultimately maintained. Approaches that illuminate these processes in model systems may enable a more general understanding of other heterogeneous nonequilibrium phenomena, and potentially define ultimate speed and energy cost limits for information processing technologies.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!