Fabrication of Flexible and Transparent Conductive Nanosheets by the UV‐Irradiation of Gold Nanoparticle Monolayers

Abstract

Conductive films that are highly transparent and flexible are extremely attractive for emerging optoelectronic applications. Currently, indium‐doped tin oxide films are the most widely used transparent conductive films and much research effort is devoted to developing alternative transparent conductive materials to overcome their drawbacks. In this work, a novel and facile approach for fabricating transparent conductive Au nanosheets from Au nanoparticles (AuNPs) is proposed. Irradiating an AuNP monolayer at the air–water interface with UV light results in a nanosheet with ≈3.5 nm thickness and ≈80% transparency in the UV–visible region. Further, the so‐fabricated nanosheets are highly flexible and can maintain their electrical conductivity even when they are bent to a radius of curvature of 0.6 mm. Fourier‐transform infrared and X‐ray photoelectron spectroscopy characterizations reveal that the transformation of the monolayer of AuNPs into the nanosheet is induced by the photodecomposition and/or photodetachment of the dodecanethiol ligands capping the AuNPs. Further, the UV‐irradiation of a hybrid monolayer consisting of AuNPs and silica particles affords the patterning of Au nanosheets with periodic hole arrays.

Conductive nanosheets produced by UV irradiation of a Ag nanoparticle monolayer at the air–water interface

“…UV irradiation resulted in the weakening of the plasmon band of Ag NPs at ∼500 nm, and the transmittance of the nanosheet was above 70% in the visible region. Because the previously reported Au nanosheets had an electrical resistance of 0.15 kΩ and an optical transmittance of ∼80%, 16 the performance of the present Ag nanosheet was roughly comparable to that of Au nanosheets, suggesting that the combination of the present UV irradiation method and additives in the water phase is generally effective for fabricating metal nanosheets from the corresponding NPs. Since the present performance was surely a little lower than that of the Au nanosheet, to achieve the best performance, further investigation of the effects of the Ag NP diameter, other additives, and their concentrations is required, which might be the object of future work.…”

“…The mechanism promoting NP fusion lies in the decomposition of the DDT covering the Ag NPs. 16,[20][21][22] More precisely, DDT decomposition may produce energetically unstable Ag NP bare surfaces, leading to NP agglomeration. 23 The decomposition is conrmed by the FT-IR spectra in Fig.…”

“…1d did not exhibit any electrical conductivity, which was in contrast with previously reported Au nanosheets prepared from Au NPs using the same UV irradiation method. 16 The absence of conductivity is most likely correlated with the morphology of the aggregates. The reason why large Ag NPs, instead of a nanosheet, are formed following UV irradiation is not sufficiently understood so far, but the difference between Au NPs and Ag NPs is possibly related to the difference in wettability or solid-state de-wetting behavior.…”

“…In a previous study, 16 we proposed a new method for fabricating ultrathin Au nanosheets by UV irradiation of Au NP monolayers at the air–water interface. UV irradiation facilitated the decomposition and detachment of ligand molecules covering the Au NPs and promoted the transformation of the Au NPs into a nanosheet.…”

Gold Nanoparticles Monolayer Doping PEDOT : PSS Janus Film for Hydrogen Sulfide Sensor

“…The electrical conductivity of the PEDOT : PSS nanocomposite could be improved by orders of magnitude due to the conductivity of noble metal nanoparticles [23,24]. The NPs can assembly into densely packed 2D membranes with improved conductivity due to more efficient transportation of electrons, ions, and phonons optimal physical properties [25][26][27]. The metal-semiconductor could be thoroughly established through combining AuNPs monolayers with PEDOT : PSS layer to save AuNPs [28].…”