| Transparent electrodes (TEs) are electrodes that simultaneously have good electrical conductivity and high optical transmittance to visible light. Nowadays some commercial transparent conducive oxides (TCOs) such as indium tin oxide (ITO) have been widely used in optoelectronic devices as transparent electrodes. They are indispensable parts on planar display, touch screen, thin film solar cells and organic light-emitting diodes. However, there are also some inherent deficiencies in these TCOs preventing their satisfactory applications in some future optoelectronic devices. For example, it is difficult to further improve their conductivity and transmittance simultaneously. Moreover, the brittleness limits their applications in flexible optoelectronic devices. Today, in order to develop low cost TEs with high transmittance, good conductivity, high stability and high flexibility, many kinds of novel materials, such as graphene, conductive polymers, carbon nanotubes and metal networks, have been widely studied. As a class of metal nanowire network TE, patterned metal nanowire networks have attracted widely attention for their outstanding electrical conductivity and optical transmittance. The aim of this study is to develop a relative low cost method to fabricate patterned metal nanowire network with high performance and flexibility.Here we develop a facile and compatible method to in situ fabricate metal nanowire networks on transparent substrates based on an ion beam etching (IBE) process with the electrospun polymer nanofiber networks as shadow masks. The as-fabricated metal nanowire networks show low sheet resistance and high transmittance (2.2 Ω/sq at T= 91.1%　and 18.7 Ω/sq at T=98.2%). The as-prepared patterned networks also have relative smooth surface roughness. For the 100 nm thick network, the root- mean-square roughness is about 55 nm. We demonstrated that the transmittance of the metal networks becomes homogeneous from deep-ultraviolet (200 nm) to near-infrared (2000 nm) when the size of the wire spacing increases to micrometer size. Theoretical and experimental analyses indicated that we can improve the conductivity of the metal networks as well as keep their transmittance by increasing the thickness of the metal films. We also carried out durability tests to demonstrate our as-fabricated metal networks having good flexibility and strong adhesion. As an example for the application, a four-wire resistive touch screen working prototype was fabricated.Organometal trihalide perovskite have been widely studied in fields of solar cells, light-emitting diodes, photodetectors, indicating their potential applications in these fields. Meanwhile, flexible perovskite devices also are widely studied. ITO, conductive polymer, graphene and carbon nanotube networks have been used as the flexible TE on the flexible perovskite devices. However, the flexibility of ITO and conductivity of conductive polymer, graphene and carbon nanotube are not good enough to fabricate devices with high flexibility and performance. Silver nanowire networks are easy to be corroded by the halogens in perovskite. Here we introduce patterned Au nanowire networks to the flexible CH3NH3PbI3 perovskite photodetectors. The Au nanowire networks based flexible perovskite photodetectors show external quantum efficiencies (EQEs) of around 50% in the visible light range with a maximum EQE of 60%. And the special detective (D*) in the visible light range are from 1 to 2×1012 Jones, which are closed to that of grid perovskite photodetectors and Si photodiodes. The flexible devices show linear response to light intensity from 0.25 μW/cm2 to 35 mW/cm2 corresponding to a linear dynamic range (LDR) of 103 dB, which is comparable to that of Si photodiodes and higher than that of InGaAs photodetectors. Meanwhile, the response time of the flexible devices is short (～4 μs). The Au nanowire networks based devices also show better flexibility compared to that based on ITO electrodes. |
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