Over the past decades, a new branch of plasma research, the nanomaterial (NM) synthesis by plasma-liquid interactions (PLIs), is rapidly rising, mainly due to the recently developed various plasma sources operated from low to atmospheric pressures. The PLIs provide novel plasma-liquid interfaces where many physical and chemical processes take place. By exploiting these physical and chemical processes, various NMs ranging from noble metal nanoparticles to graphene nanosheets can be easily synthesized. The currently rapid development and increasingly wide utilization of the PLI method naturally lead to an urgent requirement for presenting a general review. This paper reviews the current status of research on plasma-liquid 2 interactions for nanomaterial syntheses. Focus is on the comprehensive understanding of the synthesis process and perceptive opinions on the present issues and future challenges in this subject.

In this letter, Si thin film (800 nm thick) with nanopillar array decorated surface is studied via simulation for its solar energy absorption characteristics. It is found that the light absorption is significantly enhanced due to the adding of the Si nanopillar (SiNP) array to the Si thin film. The absorption characteristics of the SiNP structure would be approximately optimum (especially at ∼2.5 eV, the high energy density region in the solar spectrum) when the periodicity of SiNP array is set as ∼500 nm, which can be explained when comparing the incident light wavelength with the periodicity of SiNP array.

In this letter, optimum periodic Si nanowire (SiNW) arrays are designed via simulation for solar cell application, in terms of the structural parameters, e.g., the array periodicity (P) and SiNW diameter (D). It is found that the more efficient light absorption compared to that of the Si thin film with the same thickness could be realized when P is between 250 and 1200 nm. Further, the ratio of D to P should be >0.5 (or more specifically ∼0.8) for the optimized solar energy harvesting. The underlying physics is also discussed in this work.