Ambient Degradation of ZnO Powders: Does Surface Polarity Matter?

Abstract

Comparing different synthesis methods to investigate ambient degradation differences among ZnO crystals with different crystal habits, we examined the effects of particle size, surface area, shape (surface polarity), and zeta (surface) potential. Neither surface polarity nor surface area, on their own, can account for the differences in the surface carbonation among differently synthesized ZnO samples. Our results demonstrate that surface dissolution and carbonation tendencies must be considered together, in the context of surface polarity, to explain different propensities toward degradation in ZnO powders.

Frequency-Dependent Impedance Responses of ZnO Using UV Light

“…Although f cr oss is very consistent for a given ZnO film (typically within 10%), experimentally derived values of f cr oss for prepared under similar conditions can vary from 500 Hz -10 kHz. Preliminary experiments using other methods of producing ZnO (such as molten salt or solvothermal syntheses 14 ) also yields f cr oss values within this range, but the situation can be more complicated if the impedance response is not accurately described by a single parallel RC circuit. These variances from film to film are not surprising given that resistance is affected by variations in film thickness, as well as environmental factors such as humidity.…”

Effect of hydrogen carbonate and chloride on zinc corrosion investigated by a scanning flow cell system

“…7). In a recent publication a dissolution and carbonation sequence was reported under similar conditions, which converts ZnO into Zn 5 (OH) 6 (CO 3 ) 2 [43]. As a result, solution E destroys the initial native oxide very rapidly, reaching a high reactivity already after $300 s and the lowest OCP of -865 mV after $500 s. This is followed by a strong increase of the OCP and the polarization resistance in solution E, indicating that the anodic process is decreasing (case 4).…”

Solution derived p-ZnO/n-Si nanowire heterojunctions for photodetection

“…The next strongest peaks at (103) and (101) correspond to the incompletely grown nanowire faces. [36] These correspond to the pyramidal faces in the inset of Figure 2a, which manifest during growth before the nanowire's equilibrium surfaces fully develop. There is always some irregularity during nanowire growth, but based on its relative intensity compared to the (002) peak, and the SEM image, this effect is minimal.…”