Although solution processed metal nanowire (NW) percolation networks are a strong candidate to replace commercial indium tin oxide, their performance is limited in thin film device applications due to reduced effective electrical areas arising from the dimple structure and percolative voids that single size metal NW percolation networks inevitably possess. Here, we present a transparent electrode based on a dual-scale silver nanowire (AgNW) percolation network embedded in a flexible substrate to demonstrate a significant enhancement in the effective electrical area by filling the large percolative voids present in a long/thick AgNW network with short/thin AgNWs. As a proof of concept, the performance enhancement of a flexible phosphorescent OLED is demonstrated with the dual-scale AgNW percolation network compared to the previous mono-scale AgNWs. Moreover, we report that mechanical and oxidative robustness, which are critical for flexible OLEDs, are greatly increased by embedding the dual-scale AgNW network in a resin layer.

We demonstrate selective laser sintering of silver (Ag) nanoparticle (NP) ink using a digital micromirror device (DMD) for the facile fabrication of 2D electrode pattern without any conventional lithographic means or scanning procedure. An arbitrary 2D pattern at the lateral size of 25 μm × 25 μm with 160 nm height is readily produced on a glass substrate by a short exposure of 532 nm Nd:YAG continuous wave laser. The resultant metal pattern exhibits low electrical resistivity of 10.8 uΩ · cm and also shows a fine edge sharpness by the virtue of low thermal conductivity of Ag NP ink. Furthermore, 10 × 10 star-shaped micropattern arrays are fabricated through a step-and-repeat scheme to ensure the potential of this process for the large-area metal pattern fabrication.

Fabricating an electron extraction layer (EEL) with a metal doping transition metal oxide (TMO) in inorganic–organic hybrid perovskite solar cells (PeSCs) and organic solar cells (OSCs) is a simple and efficient process for enhancing photovoltaic properties. Here, the universal benefits and common factors that influence both PeSCs and OSCs as a result of changes in Al‐doped TiO2 properties are investigated. These common factors are identified in two separate mechanisms. The first involves surface smoothing of TiO2 films, which affects the formation of a high crystalline active layer and reduces recombination between the electron extraction and active layers. The second involves bandgap widening of TiO2, which reduces the activation energy and enhances the quenching efficiency of devices. These factors are demonstrated in various measurements. The results will help in understanding the fundamental benefits of Al‐doped TiO2 in solution‐processed thin‐film solar cells.

We demonstrate ZnO nanowire based UV sensor by laser-induced hydrothermal growth of ZnO nanowire. By inducing a localized temperature rise using focused laser, ZnO nanowire array at~15 μm size consists of individual nanowires with~8 μm length and 200~400 nm diameter is readily synthesized on gold electrode within 30 min at the desired position. The laser-induced growth process is consecutively applied on two different points to bridge the micron gap between the electrodes. The resultant photoconductive ZnO NW interconnections display 2~3 orders increase in the current upon the UV exposure at a fixed voltage bias. It is also confirmed that the amount of photocurrent can be easily adjusted by changing the number of ZnO NW array junctions. The device exhibits clear response to the repeated UV illumination, suggesting that this process can be usefully applied for the facile fabrication of low-cost UV sensor array.

In recent past, for next-generation device opportunities such as sub-10 nm channel field-effect transistors (FETs), tunneling FETs, and high-end display backplanes, tremendous research on multilayered molybdenum disulfide (MoS 2 ) among transition metal dichalcogenides has been actively performed. However, nonavailability on a matured threshold voltage control scheme, like a substitutional doping in Si technology, has been plagued for the prosperity of 2D materials in electronics. Herein, an adjustment scheme for threshold voltage of MoS 2 FETs by using self-assembled monolayer treatment via octadecyltrichlorosilane is proposed and demonstrated to show MoS 2 FETs in an enhancement mode with preservation of electrical para meters such as field-effect mobility, subthreshold swing, and current on-off ratio. Furthermore, the mechanisms for threshold voltage adjustment are systematically studied by using atomic force microscopy, Raman, temperature-dependent electrical characterization, etc. For validation of effects of threshold voltage engineering on MoS 2 FETs, full swing inverters, comprising enhancement mode drivers and depletion mode loads are perfectly demonstrated with a maximum gain of 18.2 and a noise margin of ≈45% of 1/2 V DD . More impressively, quantum dot light-emitting diodes, driven by enhancement mode MoS 2 FETs, stably demonstrate 120 cd m −2 at the gateto-source voltage of 5 V, exhibiting promising opportunities for future display application. Field-Effect Transistors