Dithieno[3,2‐b:2′,3′‐d]pyrrol‐Cored Hole Transport Material Enabling Over 21% Efficiency Dopant‐Free Perovskite Solar Cells

Dopant‐free hole transport materials (HTMs) are essential for commercialization of perovskite solar cells (PSCs). However, power conversion efficiencies (PCEs) of the state‐of‐the‐art PSCs with small molecule dopant‐free HTMs are below 20%. Herein, a simple dithieno[3,2‐b:2′,3′‐d]pyrrol‐cored small molecule, DTP‐C6Th, is reported as a promising dopant‐free HTM. Compared with commonly used spiro‐OMeTAD, DTP‐C6Th exhibits a similar energy level, a better hole mobility of 4.18 × 10^?4 cm² V^?1 s^?1, and more efficient hole extraction, enabling efficient and stable PSCs with a dopant‐free HTM. With the addition of an ultrathin poly(methyl methacrylate) passivation layer and properly tuning the composition of the perovskite absorber layer, a champion PCE of 21.04% is achieved, which is the highest value for small molecule dopant‐free HTM based PSCs to date. Additionally, PSCs using the DTP‐C6Th HTM exhibit significantly improved long‐term stability compared with the conventional cells with the metal additive doped spiro‐OMeTAD HTM. Therefore, this work provides a new candidate and effective device engineering strategy for achieving high PCEs with dopant‐free HTMs.     

DBP和NA在发射药中扩散性能的分子动力学模拟

针对钝感剂在发射药贮存期间的扩散迁移影响发射药服役寿命的问题,采用分子动力学模拟(MD模拟)比较了小分子邻苯二甲酸二丁酯(DBP)、聚新戊二醇己二酸酯(NA)在发射药体系中的扩散系数,探究了温度和硝化甘油(NG)含量对DBP、NA在双基发射药中扩散的影响,并分析了扩散机理.结果表明:5℃时DBP和NA在NC基体中的扩散能力相当,扩散系数均在10-12 m2·s-1数量级,25℃时DBP与NA的扩散系数分别为1.13×10-11 m2·s-1和5.13×10-12 m2·s-1,65℃时DBP与NA的扩散系数分别为1.88×10-11 m2·s-1和7.57×10-12 m2·s-1,85℃时DBP与NA的扩散系数分别为3.42×10-11 m2·s-1、1.11×10-11 m2·s-1,在相同温度下,钝感剂扩散系数的大小顺序为DBP>NA,这说明NA具有较好的抗迁移特性,该特性在高温时更为凸显;从微观角度分析温度对扩散机理的影响为:高温使原子间氢键作用峰值减小,即DBP、NA与NC的相互作用力减弱,并且体系的自由体积分数也变大,增大了分子运动的有效活动空间,更有利于DBP、NA扩散.DBP、NA的扩散能力随着增塑剂NG含量的增加而增强,添加NG使得DBP、NA与NC的相互作用减弱,因此DBP、NA运动更活跃,扩散能力增强.     

空间调制器——实时光处理

空间光调制器（SLM）对我们还是一个比较陌生的名词，但它却正悄悄并稳步地进入我们的日常生活。空间光调制器又称光问，实质上是个随时间变化的挡板。光学十字开关便是它众多功能中的一例。它可看作由一组线性发光体列阵组成的栅，而由一组线性光探测器列阵组成另一个栅，两者互相垂直并隔一小段距离。每个发光体都能照到所有的探测器上。如上所述，这样一种光学十字开关似乎并不引起人们的兴趣。但如在发光体列阵与探测器列阵之间插入一挡板，只有板上能透光的部分可以将特定的发光体与选定的探测器连接。这个挡板就是空间光调制器。这…     

Chlorine auto-doping by chloride vapor phase epitaxial growth of InP

Chlorine auto-doping phenomenon was found for the first time in InP epitaxial growth by using a PCl₃/InP/H₂ system. Chlorine atoms act as a donor in the epitaxial layer and the carrier concentration is dependent on the facet of InP substrate. The carrier concentration of the InP layer on ( 111)B facet was over 10³ times higher than that on (111)A substrate.     

无溶剂有机合成的促进方法及其前景

研磨、相转移催化、微波辐射和主-客体包结是用来改善无溶剂有机合成效率的主要方法。采用无溶剂有机合成不仅能减少溶剂的危害,而且能提高反应效率,因此可能成为一种有效的绿色合成方法。由于无溶剂反应体系散热困难和反应速度快,所以它不适合于剧烈放热的反应。为了实现无溶剂有机合成的工业化,应开展相关工程技术和工业设备的研究。     

焚烧过程中氯对重金属形态的影响及脱氯特性研究

目前我国国内还普遍缺乏对危险废弃物焚烧处理的机理研究，尤其是焚烧过程中关于氯、重金属排放及二者之间关系的基础研究。从这一点出发，着重研究了典型危险废弃物之一染料残渣在小型管式炉中焚烧过程中氯化氢的排放特性；并利用化学热力学平衡方法计算了焚烧过程中氯元素对多种常见重金属的排放影响；初步研究了在利用回转窑处理危险废弃物时，两种脱氯剂对烟气中氯的脱除效果。     

Diffused Phase Transition Boosts Thermal Stability of High‐Performance Lead‐Free Piezoelectrics

High piezoelectricity of (K,Na)NbO₃ (KNN) lead‐free materials benefits from a polymorphic phase transition (PPT) around room temperature, but its temperature sensitivity has been a bottleneck impeding their applications. It is found that good thermal stability can be achieved in CaZrO₃‐modified KNN lead‐free piezoceramics, in which the normalized strain d ₃₃* almost keeps constant from room temperature up to 140 °C. In situ synchrotron X‐ray diffraction experiments combined with permitivity measurements disclose the occurrence of a new phase transformation under an electrical field, which extends the transition range between tetragonal and orthorhombic phases. It is revealed that such an electrically enhanced diffused PPT contributed to the boosted thermal stability of KNN‐based lead‐free piezoceramics with high piezoelectricity. The present approach based on phase engineering should also be effective in endowing other lead‐free piezoelectrics with high piezoelectricity and good temperature stability.     

自由空间全光通信链路的设计方法

在自由空间光通信系统中 ,由于中继距离的不确定性 ,相应的链路传输损耗也不同 ,因而各中继器有不同的增益。针对自由空间光通信的这一特点 ,介绍了一种解决方法 ,即采用具有自动增益控制 ( AGC)的光放大器作为中继器 ,并分析噪声累积对系统性能的影响。结果表明 ,采用掺铒光纤放大器可以得到好的系统性能     

美国海军舰载激光武器研究进展

近年来,美国海军重点研究了可用于水面舰艇的三种激光器-光纤固体激光器、板条激光器和自由电子激光器。介绍了基于此三类激光器的几款舰载激光武器系统即"激光武器系统"、"战术激光系统"、"板条固体激光器"、"自由电子激光器"的构成、研究现状和试验进展,并讨论了其面临的关键技术问题。     

空间激光通信中基于原模图的LDPC码构造方法

研究了空间激光通信系统中的信道编码算法,基于原模图和准循环扩展,提出了一种性能优异的低密度奇偶校验(LDPC)码构造方法,可以满足光通信系统中的高速编译码需求。仿真结果表明,构造的LDPC码纠错性能强,在误码率(BER)为10-9数量级处仍未出现误码平底,适合长距离空间激光通信系统。