Versatile Sequential Casting Processing for Highly Efficient and Stable Binary Organic Photovoltaics
Chengliang He,Youwen Pan,Guanghao Lu,Baohua Wu,Xinxin Xia,Chang-Qi Ma,Zeng Chen,Haiming Zhu,Xinhui Lu,Wei Ma,Lijian Zuo,Hongzheng Chen
形成理想的体异质结 (BHJ) 形态是控制有机太阳能电池 (OSC) 中光子到电子过程的关键问题。作为 BHJ 构造中广泛使用的混合涂膜 (BC) 方法的补充，连续涂膜 (SC) 还可以为 OSC 实现相似甚至更好的形态和器件性能。
浙江大学陈红征和左立见等人在三个有代表性的供体：受体 (D:A) 混合物上使用BC和SC方法，即PM6:PC71BM、PM6:IT-4F和PM6:L8-BO。研究人员利用SC处理的有益形态在所有情况下都实现了更高的功率转换效率 (PCE)，并达到了基于PM6:L8-BO混合的18.86%（认证为 18.44%）的冠军PCE，代表了二元OSC的创纪录效率值。
此外，基于SC工艺的OSC在器件光稳定性和大规模制造方面显示出优势。这项工作证明了SC方法对基于BHJ的 OSC 的多功能性和有效性。
a） 基于不同工艺条件的共混薄膜的 RSoXS 型材。b）来自BC和SC方法的PM6：L8-BO混合胶片的2D GIWAXS图像。c） 沿面内（蓝线）和面外（红线）方向的三种混合薄膜的GIWAXS强度分布。d） 来自BC和SC方法的PM6：L8-BO混合薄膜的AFM高度（顶部）和相位（底部）图像。
Volume10, Issue16 August 18, 2022
High-Performance Inverted Tandem OLEDs with the Charge Generation Layer based on MoOx and Ag Doped Planar Heterojunction
The morphological and electrical characteristics of a planar-heterojunction structured charge generation layer (CGL) consisting of MoO3 doped N,N′-bis-(1-naphthalenyl)-N, N′-bis-phenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) as the p-type material and Ag-doped 4,7-diphenyl-1,10-phenanthroline (Bphen) as the n-type counterpart (NPB:MoO3/Bphen:Ag). A significant charge generation effect of CGL is observed and its mechanism is analyzed. The introduction of CGL can enhance the concentration of the charge carrier and balance the injection of carriers. Inverted tandem organic light-emitting diodes (OLEDs) with the CGL are fabricated. The inverted tandem OLEDs exhibit excellent optoelectronic performance due to the charge generation effect and the suppression of the high concentration quenching. The maximum current efficiency and external quantum efficiency of the inverted tandem OLED reached 27.91 cd A−1 and 11.18%, respectively, which are 110.95% and 95.79% higher than that of the inverted OLED.
Volume18, Issue32 August 11, 2022
Ferroelectric Domain Reversal Dynamics in LiNbO3 Optical Superlattice Investigated with a Real-Time Monitoring System
The optical superlattice structure derived from a periodic poling process endows ferroelectric crystals with tunable optical property regulation, which has become one of the most efficient strategies for fabricating high-efficiency optical devices. Achieving a precise superlattice structure has been the main barrier for preparation of specific optical applications due to the unclear dynamics of domain structure regulation. Herein, a real-time monitoring system for the in situ observation of periodic poling of lithium niobate is established to investigate ferroelectric domain reversal dynamics. The formation of reversed domain nuclei, growth, and expansion of the domain are monitored, which is highly related to domain growth dynamics. The nucleation and growth of domain are discussed combined with the monition of domain reversal and the variation of local electric field distribution along with finite element analysis. An electrode configuration with multiholes is proposed to use the local electric field more efficiently and controllably, which could achieve a higher domain nucleus density with high uniformity. Two-mm-thick periodically poled LiNbO3 crystals with high quality are achieved. A nonlinear light conversion from 1064.2 to 3402.4 nm is realized by the single-resonance optical parameter oscillator with a nonlinear optical efficiency up to 26.2%.
Volume32, Issue33 August 15, 2022
Biomimetic Chromotropic Photonic-Ionic Skin with Robust Resilience, Adhesion, and Stability
The growing interest in mimicry of biological skins greatly promotes the birth of high-performance artificial skins. Chameleon skins can actively transform environmental information into bioelectrical and color-change signals simultaneously through manipulating ion transduction and photonic nanostructures. Here, inspired by chameleon skins, a novel biomimetic chromotropic photonic-ionic skin (PI-skin) capable of outputting synergistic electrical and optical signals under strain with robust adhesion, stability, and resilience is ingeniously constructed. The PI-skin exhibits sensitive structural color change synchronized with electrical response via adjusting the lattice spacing of the photonic crystal (mechanochromic sensitivity: 1.89 nm per %, Δλ > 150 nm). Notably, the polyzwitterionic network provides abundant electrostatic interactions, endowing the PI-skin with excellent adhesion, environmental tolerance, and outstanding mechanical stability (>10 000 continuous cycles). Meanwhile, the high loading of ionic liquid (IL) weakens the electrostatic interaction between the polyzwitterionic molecular chains, leading to high resilience. The PI-skin is finally applied to construct a visually interactive wearable device, realizing precise human motion monitoring, remote communication, and visual localization of pressure distribution. This work not only expands design ideas for the construction of advanced biomimetic I-skins but also provides a general optical platform for high-level visual interactive devices and smart wearable electronics.
Volume 144, Issue 32 August 17, 2022
Achieving Record-Efficiency Organic Solar Cells upon Tuning the Conformation of Solid Additives
Volatile solid additives (SADs) are considered as a simple yet effective approach to tune the film morphology for high-performance organic solar cells (OSCs). However, the structural effects of the SADs on the photovoltaic performance are still elusive. Herein, two volatilizable SADs were designed and synthesized. One is SAD1 with twisted conformation, while the other one is planar SAD2 with the S···O noncovalent intramolecular interactions (NIIs). The theoretical and experimental results revealed that the planar SAD2 with smaller space occupation can more easily insert between the Y6 molecules, which is beneficial to form a tighter intermolecular packing mode of Y6 after thermal treatment. As a result, the SAD2-treated OSCs exhibited less recombination loss, more balanced charge mobility, higher hole transfer rate, and more favorable morphology, resulting in a record power conversion efficiency (PCE) of 18.85% (certified PCE: 18.7%) for single-junction binary OSCs. The universality of this study shed light on understanding the conformation effects of SADs on photovoltaic performances of OSCs.
Volume10 Issue 31,21 August 2022
Targeted therapy of atherosclerosis by zeolitic imidazolate framework-8 nanoparticles loaded with losartan potassium via simultaneous lipid-scavenging and anti-inflammation
Atherosclerosis (AS) is a condition associated with dysfunctional lipid metabolism and an inflammatory immune microenvironment that remains the leading cause of severe cardiovascular events. Drugs exhibiting both anti-inflammatory and lipid-scavenging activity hold great promise for treating AS. In this study, zeolitic imidazolate framework-8 (ZIF-8) nanoparticles loaded with losartan potassium (LP) were developed as an anti-AS treatment to target both of these therapeutic arms simultaneously. LP@ZIF-8 accumulated within AS target tissues via the enhanced permeability and retention (EPR) effect, as confirmed via in vivo near-infrared fluorescence (NIRF) imaging and was disrupted in response to the low pH. ZIF-8 could activate autophagy, thus regulating lipid metabolism and restoring cholesterol homeostasis as previously reported, while the released LP served as an anti-inflammatory angiotensin receptor blocker (ARB) inhibitor, which was confirmed via the in vivo treatment studies. As such, our data highlight LP@ZIF-8 as a promising therapeutic agent capable of attenuating the severity of AS
Volume 121, Issue 8, 22 August 2022
Ultrahigh focal sensitivity in a relaxor ferroelectric crystal-based piezoelectric adaptive lens
Traditional piezoelectric adaptive lenses (ALENS) are fabricated by piezoceramics with transparent liquids as the filling media. However, it is challenging to achieve high focal sensitivity and long-time robustness because of the low piezoelectricity of ceramics as well as the evaporation and leakage of the liquids. To overcome the above-mentioned issues, we design a piezoelectric lens based on a radial extension-arching mode by using polydimethylsiloxane films and Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIMNT) relaxor ferroelectric single crystals to replace the transparent liquids and Pb(Zr, Ti)O3 (PZT) ceramics, respectively. Due to the ultrahigh piezoelectric properties (d33 ∼ 1500 pC N−1 and d31 ∼ 730 pC N−1) of the PIMNT crystals and the optimized radial extension-arching structure, an ultrahigh focal sensitivity (8.5 cm V−1 and a fast response time (∼102 μs) is achieved, outperforming conventional ALENS based on piezoceramic actuators (∼103 μs and ∼10−1 cm V−1) and dielectric elastomer actuators (∼105 μs and ∼10−2 cm V−1). The largest output displacement of our designed ALENS is up to 53.6 μm at 4.2 kHz under 80 Vpp, and its focus is in the range of 57.44 cm to ∞. Furthermore, its performance remains unchanged after 4 × 107 vibration cycles, indicating its long-time robustness. This work sheds light on the design of advanced adaptive optical systems, where an ultrahigh focal sensitivity and a fast response are required.
Volume36, Issue1 February, 2022
Phase Field Modeling of the Evolution of Helium Bubbles in Shock Loaded Aluminum
The influence of defects such as helium bubbles on the dynamic strength of metal materials has always been the focus of dynamic strength research. By introducing the phase field method into the study of the evolution behavior of helium bubbles under impact loading, a mesoscopic simulation technique that can describe the early evolution behavior of helium bubbles under impact is established by coupling with crystal plasticity theory. Using this method, the evolutionary behavior of helium bubbles and their influence on the collective evolutionary behavior of dislocations are studied from the mesoscopic scale for helium-containing metallic aluminum materials. The results show that the non-uniformity of the helium bubble structure leads to the concentration of local stress and plastic deformation, and the concentration of local plastic deformation leads to the emission of sparse waves along the direction of shock wave propagation. From the perspective of energy conservation, helium bubble growth and plastic deformation are competitive in the process of material deformation, and the speed of plastic dissipation directly affects the growth rate of helium bubbles and changes them. The results can provide theoretical support for interpreting the macroscopic yield strength and lamination behavior of helium-containing materials.
Volume49, Issue7 2022
Survey on Action Quality Assessment Methods in Video Understanding
Action quality assessment refers to evaluate the action quality performed by human in video,such as calculating the quality score,level and evaluating the performance of different people.It is an important direction in video understanding and computer vision research.This paper summarizes the main methods of action quality assessment,including action quality score prediction methods,level classification and ranking methods.The performance of these methods on public datasets is also analyzed.Finally,the challenge problems in future research are discussed.