Words: 2500 and above excluding referencesShould cover: (i) introduction about the targeted materials (highly their key features/properties); (ii) brief discussion on how the target materials are...

Keywords:
metallic nanocrystals, Metal nanoparticles, solar energy conversion, Photocatalysis, Schottky
junction, direct electron transfer, Hot electron injection, semiconductor, noble metals,
nanostructures.
Introduction
Metallic nanocrystals are a type of nanomaterial that has garnered significant attention in recent
years for their potential use in solar energy conversion. These materials, which are typically
composed of metals such as gold, silver, or copper, have unique optical and electrical properties
that make them well-suited for use in photovoltaic cells and other solar energy technologies.
One of the key features of metallic nanocrystals is their small size, which allows them to interact
with light in unique ways. When light hits a metallic nanocrystal, it is absorbed and re-emitted at
a different energy level, a process known as plasmonic resonances. This property allows metallic
nanocrystals to convert light into electrical energy more efficiently than larger, bulk materials.
Another important property of metallic nanocrystals is their tunability. Because their size and
shape can be precisely controlled, it is possible to tailor the optical and electrical properties of
these materials to suit specific applications. This allows researchers to optimize metallic
nanocrystals for use in a wide range of solar energy technologies, from photovoltaic cells to solar
water-splitting systems.
In addition to their optical and electrical properties, metallic nanocrystals also exhibit high
chemical stability and thermal stability. This makes them resistant to degradation over time and
allows them to operate effectively at high temperatures. This is a significant advantage over
other materials used in solar energy conversion, which often suffer from degradation and
instability under similar conditions.
One potential drawback of metallic nanocrystals is their cost. The synthesis of these materials
can be complex and time-consuming, which can make them expensive to produce on a large
scale. However, researchers are currently working on ways to improve the efficiency and cost-
effectiveness of their synthesis, with the goal of making metallic nanocrystals more widely
accessible for use in solar energy technologies.
Overall, metallic nanocrystals are a promising material for use in solar energy conversion. Their
unique optical and electrical properties, high stability, and tunability make them well-suited for
use in a range of solar energy technologies. While their cost remains a challenge, ongoing
research is aimed at finding ways to make these materials more affordable and accessible for use
in solar energy applications.
One key advantage of metallic nanocrystals is their high surface-to-volume ratio. This means that
they have a large amount of surface area per unit volume, which can facilitate chemical reactions
and make them more effective at absorbing light. Additionally, metallic nanocrystals can exhibit
strong absorption of light in the visible and near-infrared spectrum, which is the part of the
spectrum that is most important for solar energy conversion.
Another important property of metallic nanocrystals is their ability to conduct electricity. This
makes them well-suited for use in solar energy technologies, where they can be used to convert
light energy into electrical energy. Additionally, the conductive properties of metallic
nanocrystals can be exploited in other ways, such as for the generation of heat or for the catalytic
conversion of chemical reactions.
While metallic nanocrystals have shown great promise for use in solar energy applications, their
use is still in the early stages of development. Ongoing research is focused on improving the
efficiency and cost-effectiveness of their synthesis, as well as developing new applications for
these materials in solar energy technologies. Some of the challenges that need to be overcome
include the need for more efficient and scalable synthesis methods, as well as the development of
new materials and designs that can further improve the performance of metallic nanocrystals in
solar energy applications.
Despite these challenges, the unique properties of metallic nanocrystals make them a promising
material for use in solar energy conversion. Their high surface-to-volume ratio and strong light
absorption, combined with their ability to conduct electricity, make them well-suited for use in a
variety of solar energy technologies. As research continues to advance in this area, it is likely
that metallic nanocrystals will play an increasingly important role in the development of efficient
and cost-effective solar energy technologies.
Figure 1: The figures show schematics of SPPs and LSPRs, respectively. illustrates plasmon resonances in
various nanostructures.
Brief discussion on how the target materials is made
The specific method used to make metallic nanocrystals will depend on the material being used.
However, some common techniques for synthesizing metallic nanocrystals include chemical
reduction, electrochemical reduction, and laser ablation. In chemical reduction, metal ions are
reduced to metal atoms by a reducing agent, resulting in the formation of metal nanoparticles. In
electrochemical reduction, metal ions are reduced to metal atoms at the surface of an electrode,
and the resulting nanoparticles are deposited on the electrode. Laser ablation involves using a
laser to vaporize a bulk piece of metal, which then condenses to form nanocrystalline particles.
Metallic nanocrystals are extremely small particles of pure metal that are typically only a few
nanometers in size. They are typically synthesized using a process called hot-injection synthesis,
which involves mixing a solution of metal salts with a reducing agent and heating the mixture to
a high temperature. The heat causes the metal ions in the solution to react with the reducing
agent, which results in the formation of metallic nanocrystals.
One of the key advantages of hot-injection synthesis is that it allows to produce highly pure
metallic nanocrystals. This is because the reducing agent used in the process is typically a pure
metal or a metal compound, which means that the resulting nanocrystals are also pure. In
contrast, other methods of synthesizing metallic nanocrystals often result in the formation of...