Seokwoo Jeon

Homogeneous distribution of graphene flakes in a polymer matrix, still preserving intrinsic material properties, is key to successful composite applications. A novel approach is presented to disperse non-oxidized graphene flakes with non-covalent functionalization of 1-pyrenebutyric acid and to fabricate nanocomposites with outstanding thermal conductivity (∼1.53 W/mK) and mechanical properties (∼1.03 GPa).

High-resolution, conformable phase masks provide a means to fabricate, in an experimentally simple manner, classes of 3D nanostructures that are technologically important but difficult to generate in other ways. In this approach, light passing through a phase mask that has features of relief comparable in dimension to the wavelength generates a 3D distribution of intensity that exposes a photopolymer film throughout its thickness. Developing this polymer yields a structure in the geometry of the

Two-dimensional (2D) transitional metal oxides (TMOs) are an attractive class of materials due to the combined advantages of high active surface area, enhanced electrochemical properties, and stability. Among the 2D TMOs, 2D tungsten oxide (WO₃) nanosheets possess great potential in electrochemical applications, particularly in electrochromic (EC) devices. However, feasible production of 2D WO₃ nanosheets is challenging due to the innate 3D crystallographic structure of WO<

Here we report the synthesis and characterization of a stable suspension of fluorescent erbium-doped titania nanoparticles and their assembly into thin films and photonic crystals. The nanoparticles were synthesized through a sol−gel process followed by peptization with tetramethylammonium hydroxide and hydrothermal treatment. As expected, following the hydrothermal treatment, X-ray diffraction shows the particles to be exclusively anatase. The nanoparticles form a stable suspension in water and

Long-lived afterglow emissions, such as room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF), are beneficial in the fields of displays, bioimaging, and data security. However, it is challenging to realize a single material that simultaneously exhibits both RTP and TADF properties with their relative strengths varied in a controlled manner. Herein, a new design approach is reported to control singlet-triplet energy splitting (∆E_ST ) in graphene qua

TiO2-based photocatalysis has been considered to be one of the most promising avenues for environmental remediation including water purification. However, several technical issues such as the limited surface area of bulk TiO2, the large band gap of TiO2, and rapid charge recombination still limit the practical application of TiO2 photocatalysts. Therefore, here we focus on two structural design strategies: (i) monolithic three-dimensional (3D) nanostructuring, and (ii) heterostructuring with gra

Abstract This article briefly describes two recently developed soft‐lithographic techniques that can be used to fabricate complex, well‐defined three‐dimensional (3D) nanostructures. The first relies on the single or multilayer transfer of thin solid ‘ink' coatings from high‐resolution rubber stamps. The second uses these stamps as conformable phase masks for proximity field nanopatterning of thin layers of transparent photopolymers. Although both techniques use the same pattern‐transfer element

Conformable phase masks, transparent photopolymers and two photon effects provide the basis for a simple, parallel lithographic technique that can form complex, but well defined three-dimensional (3D) nanostructures in a single exposure step. This paper describes the method, presents examples of its ability to form 3D nanostructures (including freestanding particles with controlled shapes) and comprehensive modeling of the associated optics. Single step, large area 3D pattern definition, subwave

Abstract Z‐scheme‐inspired tandem photoelectrochemical (PEC) cells have received attention as a sustainable platform for solar‐driven CO 2 reduction. Here, continuously 3D‐structured, electrically conductive titanium nitride nanoshells (3D TiN) for biocatalytic CO 2 ‐to‐formate conversion in a bias‐free tandem PEC system are reported. The 3D TiN exhibits a periodically porous network with high porosity (92.1%) and conductivity (6.72 × 10 4 S m −1 ), which allows for high enzyme loading and direc

A novel multidimensional strain sensor mimicking human skin is developed. In-plane and pressure subsensors are integrated into a sensor with exceptional sensitivity and selectivity capable of detecting stimuli from 3D directions.

Thermoelectric materials have attracted increased research attention as the implementation of various nanostructures has potential to improve both their performance and applicability. A traditional limitation of thermoelectric performance in bulk materials is the interconnected nature of the individual parameters (for example, it is difficult to decrease thermal conductivity while maintaining electrical conductivity), but through the rational design of nanoscale structures, it is possible to dec

MoO3 has potential advantages in price and weight over more widely studied WO3 for electrochromic devices, but it typically suffers from inferior electrochromic performance. Here, it is demonstrated that 2D MoO3 nanosheets can be formed by intercalation and exfoliation of MoS2 to form partially oxidized MoSxOy, followed by complete oxidation using a solution-phase nitric acid treatment. These fully oxidized MoO3 nanosheets retain the 2D nature of exfoliated MoS2 (70% of nanosheets are less than