Fully Solution‐Processed Conductive Films Based on Colloidal Copper Selenide Nanosheets for Flexible Electronics

Abstract

A novel colloidal synthesis of copper selenide nanosheets (NSs) with lateral dimensions of up to 3 μm is developed. This material is used for the fabrication of flexible conductive films prepared via simple drop‐casting of the NS dispersions without any additional treatment. The electrical performance of these coatings is benchmarked against copper selenide spherical nanocrystals (SNCs) in order to demonstrate the advantage of 2D morphology of the NSs for flexible electronics. In this contest, Cu2−xSe SNC films exhibit higher conductivity but lower reproducibility due to the formation of cracks leading to discontinuous films. Furthermore, the electrical properties of the films deposited on different flexible substrates following their bending, stretching and folding are studied. A comparison of Cu2−xSe SNC and CuSe NS films reveals an increased stability of the CuSe NS films under mechanical stress applied to the samples and their improved long‐term stability in air.

Plasmonic doped semiconductor nanocrystals: Properties, fabrication, applications and perspectives

“…For example, how does the carrier damping change when moving from the copper vacant copper chalcogenides (Cu 2-x E, with E=S, Se, Te) to the limit case of CuE composition? Initial works attested a purely metallic character to CuE , while the copper vacant one appears to suffer from additional damping or carrier localization due to vacancy formation [156,184,305]. The resulting dielectric functions obtained by band structure calculations of covellite CuS shows remarkable agreement with the experimental optical spectra [358].…”

“…Films of 2D nanosheets of copper selenide outperform films of spherical NCs of the same materials under mechanical stress. For example copper selenide nanosheets with lateral dimensions of up to 3 μm were used to prepare flexible conductive films by simple drop-casting:[305] the electrical conductivity of the films was almost fully recovered after bending, compared to a much severe drop in conductivity from films made of spherical NCs.This makes nanosheets better suited than spheres in flexible electronics applications [305]. The dynamic control of the LSPR of degenerately doped semiconductor NCs presents an exceptional opportunity to develop tunable optoelectronic devices.…”

Copper sulfide nanosheets with shape-tunable plasmonic properties in the NIR region

“…Its application in the field of photovoltaics was hindered through the relatively high degradation rate of the Cu x S/CdS interface (CdS served as a window layer for the p-n junction) and the Cu x S absorber [5]. However, during the last decade the attractiveness of the family of copper chalcogenides as cheap low-toxic materials gained attention after several protocols were published for nanostuctured copper chalcogenide synthesis by wet chemical methods [6][7][8][9][10][11][12][13] as promising fabrication method for solution-processable devices like flexible conductive films [11], sensors, solar cells [10,14,15], electrodes for the Li-ion batteries [16] or even moieties for cancer photothermal therapy (CuSe [17]).…”

Structural and Optoelectronic Properties of MoO3/CuSe Interfaces

“…As a result of changing the substrate, the maximum peak shifts toward lower angle indicating the presence of deformation in CuSe. The deformation may be attributed to the morphology that consists of overlapping between well oriented crystallites of CuSe and random ones of MoO 3 at the MoO 3 /CuSe interface . The calculated structural parameters presented by the crystallite size ( D ), microstrain (), and dislocation density () using the previously published equations are also shown in Table .…”