300-nm Imperceptible, Ultraflexible, and Biocompatible e-Skin Fit with Tactile Sensors and Organic Transistors
300-nm Imperceptible, Ultraflexible, and Biocompatible e-Skin Fit with Tactile Sensors and Organic Transistors
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DOI：
10.1002/aelm.201500452
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发表时间：
2016-04-01
影响因子：
6.2
通讯作者：
Someya, Takao
中科院分区：
文献类型：
--
作者：
Nawrocki, Robert A.;Matsuhisa, Naoji;Someya, Takao
DOI：10.1002/aelm. 201500452之间的人类触摸，金属物体的触摸，和没有触摸，同时免疫噪声。最后，超轻，0.7 gm− 2，它允许大量的应用，其中电子设备的重量是最重要的。图1a中示出了层压在人类受试者的手上的全功能电子皮肤，图1 B中描绘了电子皮肤设备布局。它集成了简单的电阻式触觉传感器和用于主动控制传感器信息的有机场效应晶体管（OFET）。OFET器件的电学特征为记录的平均迁移率为0.34 cm 2 Vs-1，开/关比为10.15。此外，阈值电压Vt的测量值约为− 1.72 V。在44个器件上计算的成品率记录为≤ 98%，只有一个器件出现故障。图1 c显示了典型OFET的电阻率曲线，测量时Vds=− 5 V，Vt略高于负1 V。图1 d所示为V G在0至− 5 V范围内的输出特性曲线示例。在刚性载玻片上进行制造过程后，手动分层器械并进行物理/机械柔韧性测试。将H2O分层的膜沉积到60%预拉伸的弹性体上，随后使其松弛。这导致高度不规则的表面，具有多个褶皱以使膜粘附。随后将弹性体拉伸100次以证明装置的良好粘附性和物理耐久性。在物理柔性测试之后，对器件进行电气表征，图2a中示出了典型的拉伸前和拉伸后的弯曲曲线。可以看出，器件的导通电流经历了边际增加，拉伸后的平均迁移率增加到0.39 cm 2 Vs-1，而关断电流和漏电流（IG）以及导通/关断比基本保持不变。VT也经历了-1.03 V的偏移。图2 B描绘了在器件进行电表征之后，直接置于松弛弹性体顶部的OFET膜的SEM图像。由于膜的易碎性质不允许进行直接的横截面分析，因此改为分析成角度的顶视图。所示的图像揭示了膜的极度折叠和顺应性。对插图的详细分析揭示了膜的折叠边缘（右上角），允许将弯曲半径外推至小于2 μ π ι。我们相信，这是我们的薄膜能够承受如此极端的弯曲、折叠和弹性体拉伸，同时保持其良好电气性能的主要原因。CVD沉积的生物相容性聚对二甲苯用作顶部和底部（基底）封装层，使其成为外部和内部医疗应用的理想候选材料。[27-30]对于我们的电子皮肤的生物相容性的初步调查，我们选择了一个相对简单和安全的测试，即准确监测3D结构的能力，例如印刷电路板，包装食品或生物器官的温度或形状的变化，而不影响被监测的结构，提出了一系列独特的挑战，并被称为不可感知的电子产品。[1-5]为了实现这样一个巨大的目标，将需要开发适形和柔性的电子和材料。由于薄膜的弯曲厚度以及随后的适形性以及对软组织的粘附性与其厚度的立方成比例，[6]减小其厚度可以显著降低弯曲刚度，使器械更加适形和更具粘附性。一些例子使用高…
DOI: 10.1002/aelm. 201500452 between a human touch, a touch of a metallic object, and no touch, while being immune to noise. Finally, ultralight, at 0.7 gm− 2, it allows for a multitude of applications where the weight of the electronics is of uttermost importance. A fully functioning e-skin, laminated on human subject’s hands, is shown in Figure 1a, with the e-skin device layout depicted in Figure 1 b. It incorporates simple resistive tactile sensors and organic field effect transistors (OFET) used to actively control the sensor information. OFET devices were electrically characterized with recorded average mobility of 0.34 cm 2 Vs− 1, and the ON/OFF ratio of≈ 10 5. Also, the threshold voltage Vt, was measured to be approximately− 1.72 V. The yield, calculated on 44 devices, was recorded as≈ 98%, with only a single faulty device. Figure 1 c demonstrates a transconductance curve of a typical OFET, measured for Vds=− 5 V, with Vt marginally higher than negative one volt. Figure 1 d shows an example of an output characteristic curve for V G in the range of 0 to− 5 volts. Following the fabrication process on a rigid glass slide, the devices were manually delaminated and subjected to physical/mechanical flexibility tests. The H2o-delaminated film was deposited onto a 60% prestretched elastomer that was subsequently relaxed. This resulted in a highly irregular surface, with multiple wrinkles for the film to adhere to. The elastomer was subsequently stretched 100 times to demonstrate good adhesion and physical durability of the devices. The devices were electrically characterized following the physical flexibility test, with a typical pre-and post-stretched transconductance curves shown in Figure 2 a. It can be seen that the device ON current underwent a marginal increase, with the poststretched average mobility increasing to 0.39 cm 2 Vs− 1, while the OFF and leakage (Ig) currents, as well as the ON/OFF ratios, remained largely unchanged. The V T also experienced a shift to− 1.03 V. Figure 2 b depicts SEM image of an OFET film, placed directly atop of a relaxed elastomer, after the device was electrically characterized. Because the fragile nature of the film did not allow for a direct cross-sectional analysis, angled top view was analyzed instead. The shown image reveals extremely folded and compliant nature of the film. Detailed analysis of the inset reveals a folded edge of the film (top right corner), allowing for extrapolation of a bending radius to being less than 2 µm. This, we believe, is the primary reason why our film can undergo such extreme bending, folding and elastomer stretching, while preserving its good electrical performance. The CVD-deposited biocompatible Parylene serves as the top and bottom (substrate) encapsulation layers, making it an ideal candidate for external and internal medical applications.[27–30] For our initial investigations of the biocompatibility of our e-skin, we have chosen a relatively simple and safe test, namelyThe ability to accurately monitor 3D structures, for instance changes of temperature or shape of printed circuit boards, packaged food, or biological organs, without affecting the structure being monitored, presents a unique set of challenges and has been termed imperceptible electronics.[1–5] To achieve such a hefty goal will require developing electronics and materials that are conformal and flexible. Because the bending thickness, and subsequently the conformability as well as adhesiveness to soft tissues, of a thin film is proportional to its thickness cubed,[6] decreasing its thickness can significantly reduce the bending stiffness making the devices much more conformal and more adhesive. A number of examples using high …