Degradation behaviors and mechanisms of MoS2 crystals relevant to bioabsorbable electronics

Abstract

Monolayer molybdenum disulfide (MoS 2 ) exhibits unique semiconducting and bioresorption properties, giving this material enormous potential for electronic/biomedical applications, such as bioabsorbable electronics. In this regard, understanding the degradation performance of monolayer MoS 2 in biofluids allows modulation of the properties and lifetime of related bioabsorbable devices and systems. Herein, the degradation behaviors and mechanisms of monolayer MoS 2 crystals with different misorientation angles are explored. High-angle grain boundaries (HAGBs) biodegrade faster than low-angle grain boundaries (LAGBs), exhibiting degraded edges with wedge and zigzag shapes, respectively. Triangular pits that formed in the degraded grains have orientations opposite to those of the parent crystals, and these pits grow into larger pits laterally. These behaviors indicate that the degradation is induced and propagated based on intrinsic defects, such as grain boundaries and point defects, because of their high chemical reactivity due to lattice breakage and the formation of dangling bonds. High densities of dislocations and point defects lead to high chemical reactivity and faster degradation. The structural cause of MoS 2 degradation is studied, and a feasible approach to study changes in the properties and lifetime of MoS 2 by controlling the defect type and density is presented. The results can thus be used to promote the widespread use of two-dimensional materials in bioabsorption applications.

Additive‐free Aqueous Dispersions of Two‐Dimensional Materials with Glial Cell Compatibility and Enzymatic Degradability

“…Moreover,i th as been shown that temperature, pH, and the type and concentration of ions could influence the rate of degradation. [28] These resultsconfirm the strong oxidative nature of the intermediates formed during the enzymaticc ycle of hMPO along with hypochloritei ons (HOCl). Moreover,p reviousr eports confirmed that 1T-MoS 2 sheets were much more rapidly degraded or oxidized by hydrogenp eroxidea lone when compared with hMPO/H 2 O 2 treatment, [11] while it took3 0hfor2 H-MoS 2 with hMPO/H 2 O 2 treatment.…”

“…Usually, over two months are needed to completely degrade and absorb a polycrystalline MoS 2 monolayer of approximately 200 nm size in PBS solution at 37 °C. Moreover, it has been shown that temperature, pH, and the type and concentration of ions could influence the rate of degradation [28] . These results confirm the strong oxidative nature of the intermediates formed during the enzymatic cycle of hMPO along with hypochlorite ions (HOCl).…”

Efficient passivation of monolayer MoS2 by epitaxially grown 2D organic crystals

“…3a. While the mobility of the device after passivation reserved $71% of its initial value, the bare MoS 2 device loses most of its mobility (3.8% remained) after exposed to air for 10 d due to the degradation induced by dislocations and point defects in MoS 2 [49,50]. Fig.…”

Theoretical approach to point defects in a single transition metal dichalcogenide monolayer: conductance and force calculations in MoS 2

“…Considering the low electronic density of such materials, such defects will obviously affect their electronic properties, for example by inducing metallic states or modifying the original electronic gap of the material. As a consequence, electronic transport properties or chemical reactivity might be modified [21,22]. On another hand, one can think about exploiting these new induced properties to create new nanoelectronic devices.…”