a few advantages over inorganic materials in the case of solar cells. Organic semiconductors exhibit a high absorbance coefficient, which allows the photons to be absorbed within a thin layer of the solar cells. This marginally decreases the cost of solar cell production. Additionally, organic materials have shown to be more efficient with increasing temperature, whereas inorganic materials have exhibited a loss of efficiency when the temperature increases. Even though the use of CNTs in polymer‐based solar cells have very limited efficiency, for commercial use, it is more desirable due to its low cost and various applications [110].
Nanotechnology is utilized in unconventional methods of energy production in many ways. In the case of windmills, nanotechnology can be used to enhance the operation and efficiency of it. The use of CNTs in making rotor blades results in higher fatigue resistance, shear strength, and fracture toughness [111]. Nanocomposites can also be used to coat the blade to prevent it from damage from the weather and other environmental factors. For example, super‐hydrophobic nanocomposites containing titanium power have been shown to reduce water adhesion strength, which means in extremely cold temperatures the water will not stick to the rotor blades and possibly damage them [112]. Nanocoatings and nanocomposites can also be used for corrosion protection in hydropower systems and for drilling equipment of geothermal, oil, and gas systems [113].
1.4.3.3 Energy Storage
Sustainability of energy includes more than just safe production and conversion; being able to store it for later use is quite important. Nanotechnology’s influence in energy storage can make it a safe and cost‐effective process in addition to sustainability. The simplest form of energy storage and one that most people are familiar with are batteries [114]. Most of the electronic devices that are used today are portable, which has increased the demand for an energy storage unit that is high density yet lightweight. This can be done by using nanocrystalline separator plates in batteries, which not only allow more storage of energy than conventional methods but also make the battery lightweight due to their foam‐like structure [115].
A safer alternative to fossil fuel‐generated energy is using hydrogen as an energy carrier. Hydrogen has shown the potential to hold a tremendous amount of energy and can be converted into other energy forms without releasing any harmful emissions. Various nanomaterials, especially carbon based, are good candidates for hydrogen storage due to their high absorbency, high specific area, pores, and low‐mass density [116]. Combination of single‐walled CNTs and BH₃ may work as a reversible hydrogen storage system and allow storage and release of hydrogen. This makes it optimal for hydrogen‐based fuel cells that could be used in vehicles.
1.5 Industry
Most applications of nanotechnology highlighted in this chapter are somewhat directly related to the health and sustainability of the human body. Industries can contribute to the deteriorating condition of the environment by emitting harmful gasses. It can also have a negative influence on the health of living beings through the emission of harmful gases and particles. Nanotechnology, however, is not limited to just those applications. The use of nanomaterials in various industries can produce safe materials and minimize their negative consequences. It can also increase the cost‐efficiency of the materials and make the industry economically sufficient.
1.5.1 Automotive
The data on the ownership of automobiles continues to climb as the influence of industrialization continues to spread. Along with the increase in the automotive industry comes an increase in fuel consumption, greenhouse gases, and resource usage. This in return increases the demand and cost of fuel and resources. Even though car manufacturers do put in the effort to minimize the negative consequences of automobiles and increase its efficiency, measures to achieve sustainability are rarely implemented [117]. With the introduction of nanotechnology, new opportunities to make the industry safe and sustainable have arisen. The combination of car engineering and nanotechnology has influenced change in each part of the car. For instance, the improvisation of nanomaterials such as carbon black and silica in car tires results in lower rolling resistance, abrasion resistance, friction, and extended tire life and safety; decrease in weight; and overall a superior performance. In addition, brominated isobutylene‐co‐para‐methyl styrene elastomer‐based nanoclay has proved to increase the air retention of tires by 50% in comparison with halobutyl rubbers. CNTs have also been used to enhance the tensile strength and tear strength of the tires [118]. In terms of thermal performance, nanofluids have the potential to improve the cooling rates of the engine by increasing efficiency, decreasing the weight, and making the thermal management systems more simple. They can also be added to fuel additives, coolants, engine oils and greases, and brake fluids [119–121].
1.5.2 Construction
The construction industry is a significant contributor to the world’s economy. According to the Global Construction Perspectives and Oxford Economics, China, United States, and India will experience an 85% growth in construction by 2030 [122]. It is important to consider enhancing the materials and functional properties of the construction [123]. Concrete, a predominantly used material in construction, is composed of several ingredients that have their own disadvantages. Nanomaterials can be used to alter and improve the properties of concrete. For example, adding nanosilica to concrete can improve its resistance to segregation, increases its strength of hardening, prevents calcium leaching, and decreases the ability to absorb water. In addition, using fiber sheets containing nanosilica particles and hardeners can increase the strength and durability of existing structures [124]. Some of the already mentioned nanomaterials, such as CNTs, can also be used to improve the mechanical properties of concrete [125]. During concrete production, the soil is endangered due to the carbon emission caused by the process. To prevent this, nano‐aggregate, such as C–S–H gel, can be added to concrete. This gel is able to breathe carbon dioxide into carbon and oxygen and decrease the amount of carbon emission [126]. Steel is another vital component of the construction industry due to its properties such as strength, corrosion resistance, welding ability, and low cost. The American Iron Steel Institute and the US Navy have developed steel with higher strength than usual by adding nanomaterials such as carbon nanoparticles and CNTs. This also makes the steel more cost‐effective [127].
1.6 Further Training
Although nanotechnology has various applications in the path to global sustainability, it has its risks and limitations that would need to be sorted out before any further development. The enhancement of agricultural methods with the help of nanomaterials has been discussed earlier, but its contribution to the food sector also generates some major risk factors. For one, the toxicology assessments for nanomaterials may not be sufficient enough. The current data from traditional assessments rely on mortality and sublethal endpoints. These tests are also time consuming, costly, and do not relay the data regarding delayed toxicity. The data from one of these assessments may generate a result of low toxicity, but how is that affecting the human body and the environment, in the long run, is not predictable from current methods of testing. Some have suggested using genomic and proteomic techniques for a faster and cost‐effective assessment of long‐term toxicity. However, these techniques do require the state‐of‐the‐art instrumentation [128]. When it comes to nanomaterials, the simple concentration and exposure time are not the only factors that determine its toxicity [129]. The unique properties of nanoparticles, such as size, morphology, and chemistry, could affect their toxicity. In addition, the functional groups and other contaminants present on the surface of these materials can also induce significantly greater toxicity effects than pure nanomaterials alone. These factors contribute to the necessity of redefining the risk assessments for any further nanotechnological developments [130].
1.7 Conclusion
The development of sustainability‐focused nanotechnology plays a major role in enhancing and improving the current
