Electron ptychography has recently attracted considerable interest for high resolution phase-sensitive imaging. However, to date studies have been mainly limited to radiation resistant samples as the electron dose required to record a ptychographic dataset is too high for use with beam-sensitive materials. Here we report defocused electron ptychography using a fast, direct-counting detector to reconstruct the transmission function, which is in turn related to the electrostatic potential of a two-dimensional material at atomic resolution under various low dose conditions.

The high-performance light-management slabs made of low-cost, highly emissive, and ultra-stable nanocrystal (NC)-polymer composites are desirable for application in large-area luminescent solar concentrators (LSCs).

In this work, we propose a flexible ferroelectric tunnel junction (FTJ) with a nanometer-thick single-crystalline BaTiO3 barrier prepared by exfoliating and transferring epitaxial BaTiO3 thin films onto flexible poly(styrenesulfonate)-doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) conductive electrodes using a water-soluble Sr3Al2O6 sacrificial layer. The transferred freestanding BaTiO3 films remain single crystalline and exhibit clear ferroelectric hysteresis, no matter being flat or bent. A combined piezoelectric force microscopy and conductive atomic force microscopy measurement reveals that the Pt/BaTiO3/PEDOT:PSS FTJ shows a clear polarization direction modulated tunneling resistance. By using x-ray photoelectron spectroscopy, the polarization direction-dependent electrostatic potential profile of this flexible FTJ has been reconstructed, consistent with the observed resistance modulation.

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