基于单根酞菁铜纳米线的FET式H_2S气体传感器

结合FET和一维微纳材料的优势,构筑了具有高灵敏度和低检测极限的FET式H2S气体传感器。研究结果发现,在室温条件下,器件对体积分数5×10–6至50×10–6的H2S具有良好的灵敏度和低检测极限(5×10–6)。相比于薄膜FET传感器,检测极限降至原来的1/20。与PMMA绝缘层比较研究结果显示:引起器件对H2S的高器件性能的原因主要归因于被暴露的导电沟道和微纳材料的性质。     

酞菁铜-氧化锌复合材料的制备及其气敏特性

将p型有机半导体材料酞菁铜(CuPc)和n型无机半导体材料氧化锌(ZnO)复合,得到p-n型的CuPc-ZnO复合材料,促进了目标气体在敏感层表面发生反应,提高了敏感层的气敏性能。在结晶度、形貌和结构等方面对制备的CuPc-ZnO敏感材料进行了详细表征,并对CuPc-ZnO复合材料的气敏性能进行了系统评估。结果表明无论是向CuPc中掺入少量的ZnO,还是向ZnO中掺入少量的CuPc,均可显著提高单一材料的气敏性能,这两种复合敏感材料对NO₂都展现了优异的选择性和良好的响应/恢复特性。其中,基于质量分数3%的CuPc/ZnO复合材料的传感器在150℃下对体积分数1×10^-5的NO₂的响应高达90,与基于纯ZnO的传感器相比,灵敏度明显提升,该传感器是检测NO₂的有利候选者。     

利用酞菁铅气体传感器的瞬态特性提高传感器的选择性

通过真空蒸发沉积技术在叉指状电极上制备了酞菁铅薄膜气体传感器。实验发展，酞菁铅薄膜对甲醇和丙酮这两种蒸气具有很高的灵敏度。对于甲醇蒸气，酞菁铅薄膜具有很快的响应速度，吸附和脱附时间只要2-3s，信号随即趋于稳定。对于丙酮蒸气，在吸附的初试阶段酞菁铅薄膜的响应时间与吸附甲醇蒸气时的相差不大，但酞菁铅薄膜的电阻率在经过这个快速响应变化以后并不趋向一个稳定值而是缓慢上升，最后甚至比吸附前的电阻率略高。通过电阻率-气体吸附时间响应曲线的瞬态特性分析，方便、清楚地区分了甲醇和丙酮两种液体。     

用酞菁薄膜制造的高灵敏度NO_2传感器

<正> 引言NO_2是有毒气体,所以在环境保护中要求NO_2含量低于30至40ppb,而工业卫生水平要求NO_2含量低于5ppm。本文描述的NO_2传感器,它所能检测的NO_2浓度范围为1ppb至10ppm。所用材料是酞菁化铅薄膜(LeadlPhthatocyanine,符号为PbPc)和无金属酞菁薄膜(Metal-     

气相沉积法制备含酞菁铜聚酰亚胺薄膜的光电性能

在2×10-3Pa真空度下,以酞菁铜、均苯四甲酸酐和二氨基二苯醚为原料,通过控制三源单体的加入摩尔计量、加热时间和沉积速率,在玻璃衬底上合成了含酞菁铜的聚酰胺酸,再经150℃～200℃真空加热亚胺化1 h后得到了成膜性良好的均匀含酞菁铜聚酰亚胺薄膜.红外谱图证实了所合成产物的结构,紫外-可见光吸收分析表明含酞菁铜聚酰亚胺薄膜在可见光区、近红外区具有较强的吸收,热失重分析表明所制备的含酞菁铜聚酰亚胺具有良好的热稳定性能;用简并四波混频方法测得薄膜的三阶非线性极化率为1.984×10-9esu,表现出良好的三阶非线性特性.     

In_2O_3基NO_2气体传感器的研究

利用化学沉淀法制备了In2O3粉体,采用X射线衍射(XRD)的方法得到了粉体的晶体结构,颗粒尺寸为纳米量级。以In2O3为基体材料,制作了烧结型旁热式气敏元件,通过固相掺杂的办法改善元件的气敏特性。在低于100℃的工作温度下,通过对SO2,CO,CH4,Cl2,NO2五种气体的检测,发现分别以质量分数为2%PdCl2和5%CeO2为掺杂剂的元件对NO2气体均表现出较好的敏感性,对SO2,CO,CH4,Cl2四种干扰气体的灵敏度较低,表明元件具有良好的选择性。     

光记录酞菁薄膜

本文研究了酞菁薄膜在红外区域的吸收光谱，报导了该酞菁薄膜的光记录特性．     

室温下ZnPc/MWCNTs敏感膜检测NO2

提出了一种以酞菁锌(ZnPc)掺杂多壁碳纳米管(MWCNTs)作为声表面波(SAW)传感器的敏感材料用于室温下检测二氧化氮(NO2).通过超声振荡等方法将研磨的MWCNTs和ZnPc分散于N,N-二甲基中,然后运用微量移液器滴涂到SAW器件的敏感区.我们对ZnPc/MWCNTs薄膜用扫描式电子显微镜(SEM)进行了表面形态表征.实验结果表明,基于MWCNTs的ZnPc SAW器件能在常温下检测最低浓度为10-6的NO2.在3个月内对器件的灵敏度、稳定性、选择性也进行了评估.     

High‐Performance Organic Heterojunction Phototransistors Based on Highly Ordered Copper Phthalocyanine/para‐Sexiphenyl Thin Films

High‐performance organic heterojunction phototransistors are fabricated using highly ordered copper phthalocyanine (CuPc) and para ‐sexiphenyl (p ‐6P) thin films. The p ‐6P thin film plays an important role on the performance of CuPc/p ‐6P heterojunction phototransistors. It acts as a molecular template layer to induce the growth of highly ordered CuPc thin film, which dramatically improves the charge transport and decreases the grain boundaries. On the other hand, the p ‐6P thin film can form an effective heterojunction with CuPc thin film, which is greatly helpful to enhance the light absorption and photogenerated carriers. Under 365 nm ultraviolet light irradiation, the ratio of photocurrent and dark current and photoresponsivity of CuPc/p ‐6P heterojunction phototransistors reaches to about 2.2 × 10⁴ and 4.3 × 10² A W^?1, respectively, which are much larger than that of CuPc phototransistors of about 2.7 × 10² and 7.3 A W^?1, respectively. A detailed study carried out with current sensing atomic force microscopy proves that the photocurrent is predominately produced inside the highly ordered CuPc/p ‐6P heterojunction grains, while the photocurrent produced at the boundaries between grains can be neglected. The research provides a good method for fabricating high‐performance organic phototransistors using a combination of molecular template growth and organic heterojunction.     

In2O3基NO2气体传感器的研究

利用化学沉淀法制备了In2O3粉体，采用X射线衍射（XRD）的方法得到了粉体的晶体结构，颗粒尺寸为纳米量级。以In2O3为基体材料，制作了烧结型旁热式气敏元件，通过固相掺杂的办法改善元件的气敏特性。在低于100℃的工作温度下，通过对SO2，CO，CH4，Cl2，NO2五种气体的检测，发现分别以质量分数为2%PdCl2和5%CeO2为掺杂剂的元件对NO2气体均表现出较好的敏感性，对SO2，CO，CH4，Cl2四种干扰气体的灵敏度较低，表明元件具有良好的选择性。     

Binary Molecular Layers of C60 and Copper Phthalocyanine on Au(111): Self‐Organized Nanostructuring

The binary molecular system of C₆₀ and copper phthalocyanine(CuPc) molecules has been investigated by scanning tunneling microscopy (STM) at room temperature and at 50 K. As substrate Au(111) was chosen. When C₆₀ and CuPc molecules are sequentially deposited, it is found that well‐ordered domains of both molecules may coexist simultaneously. Hence hexagonal ordering of C₆₀ and quadratic ordering of CuPc is observed side by side but no ordered mixed layer of both molecules or heteroepitaxy from one molecule on the other is found. Instead the boundaries of the CuPc domains are often decorated by C₆₀ molecules and for a particular choice of parameters, with regard to the film preparation, individual CuPc molecules may adsorb on top of a C₆₀ layer. The interaction with the underlying C₆₀ layer permits the molecules to perform a localized, hindered rotation. At room temperature the hopping frequency is so high that only the time average of the rotation is seen by STM while at 50 K the rotation is frozen and the CuPc molecule is trapped in one definite position.     

Controlling Ferromagnetic Ground States and Solitons in Thin Films and Nanowires Built from Iron Phthalocyanine Chains

Iron phthalocyanine (FePc) is a molecular semiconductor whose building blocks are 1D ferromagnetic chains. It is shown that its optical and magnetic properties are controlled by the growth strategy, obtaining extremely high coercivities of over 1 T and modulating the exchange constant between 15 and 29 K through switching from thin films with controlled orientations, to ultralong nanowires. Magnetization measurements are analyzed using concepts and formulas with broad applicability to all 1D ferromagnetic chains. They show that FePc is best described by a xy model with moments preferentially lying in the molecular planes. The chain Hamiltonian is very similar to that for the classic inorganic magnet CsNiF₃, but with ferromagnetic rather than antiferromagnetic interchain interactions. The dominant degrees of freedom are topological excitations called solitons, namely moving 1D magnetic domain walls, and at low temperatures and fields a “super‐Curie–Weiss” law characteristic of nearly 1D xy and Heisenberg ferromagnets, where susceptibility scales as 1/(T²–θ²), is observed. The ability to control the molecular orientation and ferromagnetism of FePc systems, and produce them on flexible substrates, together with excellent transistor characteristics reported previously for phthalocyanine analogues, makes them potentially useful for magneto‐optical and spintronic devices.     

Flexible and Highly Sensitive Pressure Sensors Based on Bionic Hierarchical Structures

The rational design of high‐performance flexible pressure sensors attracts attention because of the potential applications in wearable electronics and human–machine interfacing. For practical applications, pressure sensors with high sensitivity and low detection limit are desired. Here, ta simple process to fabricate high‐performance pressure sensors based on biomimetic hierarchical structures and highly conductive active membranes is presented. Aligned carbon nanotubes/graphene (ACNT/G) is used as the active material and microstructured polydimethylsiloxane (m‐PDMS) molded from natural leaves is used as the flexible matrix. The highly conductive ACNT/G films with unique coalescent structures, which are directly grown using chemical vapor deposition, can be conformably coated on the m‐PDMS films with hierarchical protuberances. Flexible ACNT/G pressure sensors are then constructed by putting two ACNT/G/PDMS films face to face with the orientation of the ACNTs in the two films perpendicular to each other. Due to the unique hierarchical structures of both the ACNT/G and m‐PDMS films, the obtained pressure sensors demonstrate high sensitivity (19.8 kPa^?1, <0.3 kPa), low detection limit (0.6 Pa), fast response time (<16.7 ms), low operating voltage (0.03 V), and excellent stability for more than 35 000 loading–unloading cycles, thus promising potential applications in wearable electronics.     

Ultra-Stable and Sensitive Ultraviolet Photodetectors Based on Monocrystalline Perovskite Thin Films

The detection of ultraviolet (UV) radiation with effective performance and robust stability is essential to practical applications. Metal halide single-crystal perovskites (ABX₃) are promising next-generation materials for UV detection. The device performance of all-inorganic CsPbCl₃ photodetectors (PDs) is still limited by inner imperfection of crystals grown in solution. Here wafer-scale single-crystal CsPbCl₃ thin films are successfully grown by vapor-phase epitaxy method, and the as-constructed PDs under UV light illumination exhibit an ultralow dark current of 7.18 pA, ultrahigh ON/OFF ratio of ≈5.22 × 10⁵, competitive responsivity of 32.8 A W⁻¹, external quantum efficiency of 10867% and specific detectivity of 4.22 × 10¹² Jones. More importantly, they feature superb long-term stability toward moisture and oxygen within twenty-one months, good temperature tolerances at low and high temperatures. The ability of the photodetector arrays for excellent UV light imaging is further demonstrated.     

基于局部基底弯曲法的高灵敏度薄膜应力测试技术

针对MEMS(micro-electro-mechanical system)和NEMS(nano-electro-mechanical system)对薄膜应力测试的要求,开发了一种新型高灵敏度薄膜应力测试技术,使用自行搭建的准纳米光学干涉测试系统,利用局部基底弯曲来检测薄膜的内应力.该方法不仅保留了传统基底弯曲法的所有优点,而且消除了其系统误差.使用ANSYS对测试结构进行了模拟和优化,对于30nm厚的薄膜,应力检测的分辨率为1.5MPa,优于目前国际上的相关报道.本测试结构使用各向异性腐蚀和DRIE(deep reactive ion etching)完成,加工工艺简单实用.文中使用该测试技术对常用MEMS薄膜的残余应力进行了测量,结果与其他测试方法得到的结果基本一致,测量重复性优于1%.该技术可以用于测试纳米级薄膜及超低应力薄膜的内应力.