Advanced Characterization and Optimization of NiOx:Cu-SAM Hole-Transporting Bi-Layer for 23.4% Efficient Monolithic Cu(In,Ga)Se2-Perovskite Tandem Solar Cells

The performance of five hole-transporting layers (HTLs) is investigated in both single-junction perovskite and Cu(In, Ga)Se₂ (CIGSe)-perovskite tandem solar cells: nickel oxide (NiO_x,), copper-doped nickel oxide (NiO_x:Cu), NiO_x+SAM, NiO_x:Cu+SAM, and SAM, where SAM is the [2-(3,-6Dimethoxy-9H-carbazol-9yl)ethyl]phosphonic acid (MeO-2PACz) self-assembled monolayer. The performance of the devices is correlated to the charge-carrier dynamics at the HTL/perovskite interface and the limiting factors of these HTLs are analyzed by performing time-resolved and absolute photoluminescence ((Tr)PL), transient surface photovoltage (tr-SPV), and X-ray/UV photoemission spectroscopy (XPS/UPS) measurements on indium tin oxide (ITO)/HTL/perovskite and CIGSe/HTL/perovskite stacks. A high quasi-Fermi level splitting to open-circuit (QFLS-V_oc) deficit is detected for the NiO_x-based devices, attributed to electron trapping and poor hole extraction at the NiO_x-perovskite interface and a low carrier effective lifetime in the bulk of the perovskite. Simultaneously, doping the NiO_x with 2% Cu and passivating its surface with MeO-2PACz suppresses the electron trapping, enhances the holes extraction, reduces the non-radiative interfacial recombination, and improves the band alignment. Due to this superior interfacial charge-carrier dynamics, NiO_x:Cu+SAM is found to be the most suitable HTL for the monolithic CIGSe-perovskite tandem devices, enabling a power-conversion efficiency (PCE) of 23.4%, V_oc of 1.72V, and a fill factor (FF) of 71%, while the remaining four HTLs suffer from prominent V_oc and FF losses.     

High-Performance Green Thick-Film Ternary Organic Solar Cells Enabled by Crystallinity Regulation

The power conversion efficiency (PCE) of organic solar cells (OSCs) has reached high values of over 19%. However, most of the high-efficiency OSCs are fabricated by spin-coating with toxic solvents and the optimal photoactive layer thickness is limited to 100 nm, limiting practical development of OSCs. It is a great challenge to obtain ideal morphology for high-efficiency thick-film OSCs when using non-halogenated solvents due to the unfavorable film formation kinetics. Herein, high-efficiency ternary thick-film (300 nm) OSCs with PCE of 15.4% based on PM6:BTR-Cl:CH1007 are fabricated by hot slot-die coating using non-halogenated solvent (o-xylene) in the air. Compared to PM6:BTR-Cl:Y6 blends, the stronger pre-aggregation of CH1007 in solution induces the earlier aggregation of CH1007 molecules and longer aggregation time, and thus results in high and balanced crystallinity of donors and acceptor in CH1007-based ternary film, which led to high-carrier mobility and suppressed charge recombination. The ternary strategy is further used to fabricate high-efficiency, thick-film, large-area, and flexible devices processed from non-halogenated solvents, paving the way for industrial development of OSCs.     

PEDOT:PSS‐Assisted Exfoliation and Functionalization of 2D Nanosheets for High‐Performance Organic Solar Cells

Here, a facial and scalable method for efficient exfoliation of bulk transition metal dichalcogenides (TMD) and graphite in aqueous solution with poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) to prepare single‐ and few‐layer nanosheets is demonstrated. Importantly, these TMD nanosheets retain the single crystalline characteristic, which is essential for application in organic solar cells (OSCs). The hybrid PEDOT:PSS/WS₂ ink prepared by a simple centrifugation is directly integrated as a hole extraction layer for high‐performance OSCs. Compared with PEDOT:PSS, the PEDOT:PSS/WS₂‐based devices provide a remarkable power conversion efficiency due to the “island” morphology and benzoid–quinoid transition. This study not only demonstrates a novel method for preparing single‐ and few‐layer TMD and graphene nanosheets but also paves a way for their applications without further complicated processing.     

光纤宏弯损耗性能影响因素的仿真研究

为了优选宏弯损耗敏感光纤,研发基于光纤宏弯损耗的光学器件,对影响单模光纤宏弯损耗的主要因素进行了理论分析和仿真研究。基于D.Marcuse和H.Renner提出的光纤宏弯损耗理论模型,选取SMF28、SMF28e和1060XP三种单模光纤,仿真研究了涂覆层、弯曲半径、光源波长、MAC值和弯曲圈数对光纤宏弯损耗性能的影响。结果表明:无涂覆层、带吸收层的单模光纤宏弯损耗随着波长增长而增大、随着弯曲半径增大而减小、随着圈数增多而增大、随着MAC值增大而增大;光纤的丙烯酸酯类涂覆层会引起宏弯损耗随弯曲半径变化发生振荡;MAC值是衡量光纤宏弯损耗敏感性能的指标,也是优选宏弯损耗敏感光纤的重要参数。因此,光纤宏弯损耗器件适合选用MAC值大的光纤,去除其涂覆层,增加吸收层,然后选择较长的波长、较小的弯曲半径和适当多的弯曲圈数。     

辽东地区构造演化及其对构造样式的影响

基于三维地震数据、岩心和测井数据,将辽东地区新生界自下而上划分为孔店组-沙河街组、东营组和馆陶组、新近系-第四系三套构造层。构造层的发育分别对应于盆地演化的强烈伸展断陷期、强走滑断坳转换期和热沉降坳陷期三个阶段。对应于各阶段构造的差异活动,各构造层断裂的发育特征存在差异。下部构造层以发育NNE向正断层为主,断裂组合以伸展构造样式为主;中部构造层以NNE向走滑断裂为主,断裂组合以走滑构造样式为主;上部构造层多为NE向次级断裂,断裂发育组合以弱走滑构造样式为主。     

Ligand‐Free Synthesis of Aluminum‐Doped Zinc Oxide Nanocrystals and their Use as Optical Spacers in Color‐Tuned Highly Efficient Organic Solar Cells

The color of polymer solar cells using an opaque electrode is given by the reflected light, which depends on the composition and thickness of each layer of the device. Metal‐oxide‐based optical spacers are intensively studied in polymer solar cells aiming to optimize the light absorption. However, the low conductivity of materials such as ZnO and TiO₂ limits the thickness of such optical spacers to tenths of nanometers. A novel synthesis route of cluster‐free Al‐doped ZnO (AZO) nanocrystals (NCs) is presented for solution processing of highly conductive layers without the need of temperature annealing, including thick optical spacers on top of polymer blends. The processing of 80 nm thick optical spacers based on AZO nanocrystal solutions on top of 200 nm thick polymer blend layer is demonstrated leading to improved photocurrent density of 17% compared to solar cells using standard active layers of 90 nm in combination with thin ZnO‐based optical spacers. These AZO NCs also open new opportunities for the processing of high‐efficiency color tuned solar cells. For the first time, it is shown that applying solution‐processed thick optical spacer with polymer blends of different thicknesses can process solar cells of similar efficiency over 7% but of different colors.     

基于逻辑输入样本的神经网络算法

本文对确定多层前向神经网络权提出了一种基于逻辑输入样本的直接算法。对于逻辑输入样本,该算法只需一个三层网络实现;否则,需在输入层和隐层间引入一个预处理层以完成输入样本向逻辑向量的转化。由于不引入误差能量函数,该算法避免了BP算法训练过程出现的收敛速度慢和误差陷入局部极小问题。本文还对该算法的正确性作了详细论证并以XOR问题解释其计算过程。     

Third generation multi-layer tandem solar cells for achieving high conversion efficiencies

Different ways of connecting solar cell structures to form multi-layer tandem solar cells have been considered by re-visiting relevant device designs. It is found that the present use of a series connection or tunnel junction approach is detrimental to charge-carrier collection in the tandem cells. Each tunnel junction introduced to the solar cell structure decelerates the charge carriers and allows them to recombine at the vicinity of the tunnel junction. The adoption of parallel connections has several advantages over series connections and there is high potential for achieving enhanced efficiencies in third generation tandem solar cells. In these devices, charge carriers are continuously accelerated across the whole device and collected in the external circuit. Multi charge-carrier production and impurity photo-voltaic mechanisms are also built into this system to enhance its performance by increasing the short-circuit current density.     

Correlation between chemical and electrical profiles in Si+, Se+ and S+ implanted bulk and epitaxial GaAs

We compare the chemical profiles of Cr, Mn, Si and Se with the electron concentration profiles in Si, Se and S implanted semi-insulating Cr-O doped bulk GaAs substrates and undoped VPE buffer layers annealed with and without a SiO₂ encapsulant in a H₂-As₄ atmosphere. A higher activation efficiency in the net electron concentration and the gateless saturated channel current is measured for SiO₂ encapsulated wafers annealed under arsine overpressure than for capless annealed ones using Cr-O doped bulk GaAs substrates. On the other hand, the net donor concentration peak is higher for implanted buffer epi layers capless annealed under arsine overpressure than for SiO₂ encapsulated ones. Secondary ion mass spectrometry (SIMS) studies of the Cr decoration of the implant damage indicate that the damage from the 100 keV Si implant anneals out at 840°C while a temperature of 900°C is required to anneal out the 260 keV Se implant damage. An explanation of these differences is provided using an impurity redistribution model and charge neutrality considerations. Excellent Hall electron mobilities at liquid nitrogen temperature of 5400–9200 cm²/V-sec are measured for Si-implanted buffer epi substrates.     

土工格栅与铜矿尾矿界面作用特性的实验研究

钢塑复合土工格栅的加筋效果好于其它筋材的原因在于其表面结构特性,在生产过程中塑料表面处理时,肋条压制成粗糙的花纹,以增强格栅表面的粗糙程度,提高CATT钢塑复合土工格栅与土体的摩擦系数。它与土之间不仅存在表面摩擦力,而且还存在镶嵌咬合力,从而增强加筋土体的稳定性。文中以不同规格的钢塑复合土工格栅作为加筋材料,以有色金属铜矿的尾矿作为填料土,通过拉拔实验,研究钢塑复合土工格栅与铜矿尾矿填料土的界面作用特性,获得了筋--土之间的剪切强度系数(C、φ)、似摩擦系数f*等结果,并对它们的影响因素进行了分析与探讨。