Facile and Green Synthesis of Graphene-Based Conductive Adhesives via Liquid Exfoliation Process

Graphene to Advanced MoS2: A Review of Structure, Synthesis, and Optoelectronic Device Application

In contrast to zero-dimensional (0D), one-dimensional (1D), and even their bulk equivalents, in two-dimensional (2D) layered materials, charge carriers are confined across thickness and are empowered to move across the planes. The features of 2D structures, such as quantum confinement, high absorption coefficient, high surface-to-volume ratio, and tunable bandgap, make them an encouraging contestant in various fields such as electronics, energy storage, catalysis, etc. In this review, we provide a gentle introduction to the 2D family, then a brief description of transition metal dichalcogenides (TMDCs), mainly focusing on MoS2, followed by the crystal structure and synthesis of MoS2, and finally wet chemistry methods. Later on, applications of MoS2 in dye-sensitized, organic, and perovskite solar cells are discussed. MoS2 has impressive optoelectronic properties; due to the fact of its tunable work function, it can be used as a transport layer, buffer layer, and as an absorber layer in heterojunction solar cells. A power conversion efficiency (PCE) of 8.40% as an absorber and 13.3% as carrier transfer layer have been reported for MoS2-based organic and perovskite solar cells, respectively. Moreover, MoS2 is a potential replacement for the platinum counter electrode in dye-sensitized solar cells with a PCE of 7.50%. This review also highlights the incorporation of MoS2 in silicon-based heterostructures where graphene/MoS2/n-Si-based heterojunction solar cell devices exhibit a PCE of 11.1%.

A Novel Preparation Method of Electrically Conductive Adhesives by Powder Spraying Process

In a conventional electrically conductive adhesive (ECA) preparation process, typical ECAs are made by adding an appropriate amount of electrically conductive fillers, such as silver, into a polymer matrix, such as epoxy resin, to form a uniformly dispersed mixture by mixing and stirring operations. However, during the preparation process, secondary pollution and mass loss are caused by the vigorous mixture process. At the same time, the stirring operation introduces many small and stable bubbles, which affect the electrical conductivity of the ECAs. In light of these problems with the conventional preparation of ECAs, we developed a novel ECA preparation method that employs a powder spraying process: silver flakes are sprayed into the epoxy resin with a certain mass fraction to form formulated pastes. The as-prepared ECAs exhibited excellent properties compared with those prepared by the conventional process. This proves that the powder spraying process is feasible and superior to the conventional process.