Hole-Transporting Transistors and Circuits Based on the Transparent Inorganic Semiconductor Copper(I) Thiocyanate (CuSCN) Processed from Solution at Room Temperature
Hole-Transporting Transistors and Circuits Based on the Transparent Inorganic Semiconductor Copper(I) Thiocyanate (CuSCN) Processed from Solution at Room Temperature
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DOI：
10.1002/adma.201202758
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发表时间：
2013-03-13
影响因子：
29.4
通讯作者：
Anthopoulos, Thomas D.
中科院分区：
文献类型：
--
作者：
Pattanasattayavong, Pichaya;Yaacobi-Gross, Nir;Anthopoulos, Thomas D.
宽禁带半导体易于在大面积衬底上加工，在同时需要光学透明度和电荷传输的许多光电应用中具有巨大的潜力。例如，它们可以用作透明的电荷传输层，用于诸如光伏电池和发光二极管等应用一个众所周知的家族的宽带隙半导体是金属氧化物，二氧化钛和氧化锌是其中研究最多的材料。[3-5]许多金属氧化物的一个重要特性是它们的加工多功能性。例如，它们可以使用基于溶液的技术在低温下沉积，例如喷墨印刷，自旋铸造和喷涂，[8]到不同类型的基板上（例如，玻璃或塑料），从而提供一些类似于其他新兴技术（如有机半导体）中遇到的功能另一个令人非常感兴趣的应用领域是用于大面积微电子的薄膜晶体管（TFTs），如有机发光二极管（OLED）显示器的驱动背板，[10-13]在短时间内，氧化物半导体在分立器件性能方面已经成功超越了现有技术，如氢化非晶硅（A - si）：H),[14]，它们现在正在迅速接近更先进的技术，如多晶硅（poly-Si） tft所达到的性能水平。[15-17]然而，尽管取得了巨大的进步，但基于氧化物或替代材料的透明微电子的进一步发展，由于普遍缺乏具有可与n型半导体相媲美的电荷输运特性的空穴输运（p型）半导体而受到阻碍。[13,18 - 21]目前，大多数报道的p型氧化物tft都是基于cu2o[18,19]或SnO x， [20,21] cu2o的带隙仅为≈2.1 eV，呈现黄色或红色，产生性能较差的tft。另一方面，由于tft具有良好的特性，SnO x已成为更有前途的候选者，其光带隙一般报道为2.5-3.0 eV；然而，更仔细地观察吸收光谱表明，它在低得多的能量处有一个间接的间隙，≈0.7 eV.[22]delafote家族CuMO 2 （M= Al, Ga, or In）是另一组已获得重要兴趣的透明p型半导体材料尽管研究努力激增，但到目前为止还没有基于这种材料的电子设备的报道。因此，发现和/或开发具有明显输运特性和加工多功能性的新型p型宽带隙透明半导体将是开发下一代廉价大面积光电器件的必要条件。迄今为止，一种有趣的无机分子化合物在光伏器件中作为透明空穴转运体的用途有限，它是假卤化物硫氰酸铜（CuSCN）。[24-26] CuSCN是少数已知的既具有高光学透明度的化合物之一，这是其宽带隙（3.7-3.9 eV）的直接结果[27-30]，又具有显著的p型导电性。[24,25,31,32]最重要的是，CuSCN价格低廉，可以在室温下使用合适的溶剂从溶液中加工，因此使其成为使用高通量制造工艺在廉价柔性塑料基板上制造透明电子产品的理想候选材料。然而，尽管CuSCN具有吸引人的特性，但它在薄膜晶体管中的应用还有待探索。在这里，我们报道……的发展。
Wide-bandgap semiconductors that are easy to process over large-area substrates hold great potential for numerous opto/electronic applications where optical transparency and charge transport are concurrently required. For example, they can be used as transparent charge-transporting layers in applications such as photovoltaics [1] and light-emitting diodes.[2] A wellknown family of wide-bandgap semiconductors is metal oxides, with TiO 2 and ZnO being amongst the most studied materials.[3–5] An important attribute of many metal oxides is their processing versatility. For instance, they can be deposited at low temperatures using solution-based techniques such as ink-jet printing,[6] spin-casting [7] and spray-coating,[8] onto different types of substrates (eg, glass or plastic), hence offering some capabilities similar to those encountered in other emerging technologies such as organic semiconductors.[9] A further application area of enormous interest is thin-film transistors (TFTs) for large-area microelectronics such as driving backplanes for organic light-emitting diode (OLED) displays,[10–13] where in a short period of time oxide semiconductors have managed to outperform, in terms of discrete device performance, incumbent technologies such as hydrogenated amorphous silicon (a-Si: H),[14] and they are now fast approaching the performance level achieved by more advanced technologies such as polycrystalline silicon (poly-Si) TFTs.[15–17] Despite the tremendous progress, however, further development in transparent microelectronics, based either on oxides or alternative materials, is hindered by the generic lack of hole-transporting (p-type) semiconductors with charge transport characteristics comparable to those found in their n-type counterparts.[13, 18–21] At present, most of the reported p-type oxide TFTs are based on either Cu 2O [18, 19] or SnO x.[20, 21] Cu 2O has a bandgap of only≈ 2.1 eV, appearing as yellow or red and yielding TFTs with poor performance. SnO x on the other hand has emerged as a more promising candidate with TFTs showing good characteristics, and its optical bandgap is generally reported as 2.5–3.0 eV; however, a closer look at the absorption spectrum suggests that it has an indirect gap at a much lower energy,≈ 0.7 eV.[22] The delafossite family CuMO 2 (M= Al, Ga, or In) is another group of materials which have attained significant interest as transparent p-type semiconductors.[23] Despite a surge of research effort, no electronic devices based on such materials have been reported so far. Thus, discovery and/or development of new p-type wide-bandgap transparent semiconductors with appreciable transport characteristics and processing versatility would be required for the development of next generation, inexpensive large-area opto/electronics. One interesting inorganic molecular compound that has so far found limited use as a transparent hole transporter in photovoltaic devices is the pseudohalide copper (I) thiocyanate (CuSCN).[24–26] CuSCN is one of the very few known compounds that exhibits both high optical transparency–a direct consequence of its wide bandgap (3.7–3.9 eV)[27–30]–and significant p-type conductivity.[24, 25, 31, 32] Most importantly, CuSCN is inexpensive and can be processed from solution using suitable solvents at room temperature,[33] thus making it an ideal candidate for application in transparent electronics fabricated using high throughput manufacturing processes onto inexpensive flexible plastic substrates. In spite of its attractive characteristics, however, the use of CuSCN has yet to be explored for thin-film transistor applications. Here, we report the development of …