In complex, correlated oxides, heterointerfaces have emerged as key focal points of current condensed matter science. [1][2][3] For ferroic oxides, in order to minimize the total energy, domain walls emerge as natural interfaces. Multiferroic materials show a wealth of controllable multiple ferroic order through stress, optical excitation, electric, or magnetic fi elds in the same phase, which in turn suggest potential applications in the realization of oxide-based electronic devices, such as spintronics, information storage devices, or communications. [4][5][6][7] According to the detailed classifi cation given by Mermin in ferroic systems, [ 8 ] domain walls in ferroic systems are considered as two dimensional (2D) topological defects, which play an important role in determining the functionality in materials with long-range order.Recently, several key studies pointed out interesting observations on domain walls in multiferroics. [9][10][11][12][13] For example, Y. Tokunaga et al. showed that ferroelectric polarization and magnetization are successfully controlled by magnetic and electric fi elds in GdFeO 3 , respectively, which is attributed to the unique feature of composite domain wall clamping. [ 14 ] T. Choi et al. observed insulating interlocked ferroelectric and structural antiphase domain walls in a multiferroic YMnO 3 system. [ 15 ] H. Bea et al. pointed out that domain walls are the source of the exchange bias interaction between the ferromagnetic metal layer and multiferroic BiFeO 3 (BFO). [ 16 ] Additionally, L. W. Martin further confi rmed that as-grown 109 ° domain walls in BFO thin fi lms are the contribution for uncompensated spins. [ 17 ] In addition to the above, a very recent work has established electrical conductivity at written multiferroic domain walls in BFO at room temperature, which opens up a pathway by which to manipulate domain walls for next generation nanoelectronics.Exploring details on electronic states of domain polarization reorientations is critical in oxide multiferroic materials. Theoretically, the consideration of the evolution of the polarization across the 109 ° domain walls exhibits a large potential step. The prediction correlates with the enhanced electrical conductivity due to the generation of a space-charge layer for screening the potential discontinuity in the region of the wall. [ 2 ] Experimentally, conductive atomic force microscopy (c-AFM) studies show the occurrence of electrical conduction at 109 ° domain walls within the limited spatial resolution of the experimental technigue. [ 3 ] In spite of the critical importance of these discoveries at such an oxide interface, there have been no effectively direct investigations of the intrinsic evolution of the electronic properties at regions of domain walls specifi cally within the nanoscale.In this work, we explore the subject by measuring the local electronic structure using scanning tunneling microscopy (STM) in a cross-sectional geometry. STM and scanning tunneling spectroscopy (STS) studies provide direct exp...

The presence of the PbI passivation layers at perovskite crystal grains has been found to considerably affect the charge carrier transport behaviors and device performance of perovskite solar cells. This work demonstrates the application of a novel light-modulated scanning tunneling microscopy (LM-STM) technique to reveal the interfacial electronic structures at the heterointerfaces between CHNHPbI perovskite crystals and PbI passivation layers of individual perovskite grains under light illumination. Most importantly, this technique enabled the first observation of spatially resolved mapping images of photoinduced interfacial band bending of valence bands and conduction bands and the photogenerated electron and hole carriers at the heterointerfaces of perovskite crystal grains. By systematically exploring the interfacial electronic structures of individual perovskite grains, enhanced charge separation and reduced back recombination were observed when an optimal design of interfacial PbI passivation layers consisting of a thickness less than 20 nm at perovskite crystal grains was applied.

Objective To assess the efficacy and safety of different endoscopic surgical treatments for benign prostatic hyperplasia. Design Systematic review and network meta-analysis of randomised controlled trials. Data sources A comprehensive search of PubMed, Embase, and Cochrane databases from inception to 31 March 2019. Study selection Randomised controlled trials comparing vapourisation, resection, and enucleation of the prostate using monopolar, bipolar, or various laser systems (holmium, thulium, potassium titanyl phosphate, or diode) as surgical treatments for benign prostatic hyperplasia. The primary outcomes were the maximal flow rate (Qmax) and international prostate symptoms score (IPSS) at 12 months after surgical treatment. Secondary outcomes were Qmax and IPSS values at 6, 24, and 36 months after surgical treatment; perioperative parameters; and surgical complications. Data extraction and synthesis Two independent reviewers extracted the study data and performed quality assessments using the Cochrane Risk of Bias Tool. The effect sizes were summarised using weighted mean differences for continuous outcomes and odds ratios for binary outcomes. Frequentist approach to the network meta-analysis was used to estimate comparative effects and safety. Ranking probabilities of each treatment were also calculated. Results 109 trials with a total of 13 676 participants were identified. Nine surgical treatments were evaluated. Enucleation achieved better Qmax and IPSS values than resection and vapourisation methods at six and 12 months after surgical treatment, and the difference maintained up to 24 and 36 months after surgical treatment. For Qmax at 12 months after surgical treatment, the best three methods compared with monopolar transurethral resection of the prostate (TURP) were bipolar enucleation (mean difference 2.42 mL/s (95% confidence interval 1.11 to 3.73)), diode laser enucleation (1.86 (−0.17 to 3.88)), and holmium laser enucleation (1.07 (0.07 to 2.08)). The worst performing method was diode laser vapourisation (−1.90 (−5.07 to 1.27)). The results of IPSS at 12 months after treatment were similar to Qmax at 12 months after treatment. The best three methods, versus monopolar TURP, were diode laser enucleation (mean difference −1.00 (−2.41 to 0.40)), bipolar enucleation (0.87 (−1.80 to 0.07)), and holmium laser enucleation (−0.84 (−1.51 to 0.58)). The worst performing method was diode laser vapourisation (1.30 (−1.16 to 3.76)). Eight new methods were better at controlling bleeding than monopolar TURP, resulting in a shorter catheterisation duration, reduced postoperative haemoglobin declination, fewer clot retention events, and lower blood transfusion rate. However, short term transient urinary incontinence might still be a concern for enucleation methods, compared with resection methods (odds ratio 1.92, 1.39 to 2.65). No substantial inconsistency between direct and indirect evidence was detected in primary or secondary outcomes. Conclusion Eight new endoscopic surgical methods for benign prostatic hyperplasia appeared to be superior in safety compared with monopolar TURP. Among these new treatments, enucleation methods showed better Qmax and IPSS values than vapourisation and resection methods. Study registration CRD42018099583.

Ultrastrong and precisely controllable n-type photoinduced doping at a graphene/TiOx heterostructure as a result of trap-state-mediated charge transfer is demonstrated, which is much higher than any other reported photodoping techniques. Based on the strong light-matter interactions at the graphene/TiOx heterostructure, precisely controlled photoinduced bandgap opening of a bilayer graphene device is demonstrated.

Using cross-sectional scanning tunneling microscope (XSTM) with samples cleaved in situ in an ultrahigh vacuum chamber, this study demonstrates the direct visualization of high-resolution interfacial band mapping images across the film thickness in an optimized bulk heterojunction polymer solar cell consisting of nanoscale phase segregated blends of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). We were able to achieve the direct observation of the interfacial band alignments at the donor (P3HT)-acceptor (PCBM) interfaces and at the interfaces between the photoactive P3HT:PCBM blends and the poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) anode modification layer with an atomic-scale spatial resolution. The unique advantage of using XSTM to characterize polymer/fullerene bulk heterojunction solar cells allows us to explore simultaneously the quantitative link between the vertical morphologies and their corresponding local electronic properties. This provides an atomic insight of interfacial band alignments between the two opposite electrodes, which will be crucial for improving the efficiencies of the charge generation, transport, and collection and the corresponding device performance of polymer solar cells.