tugas nanotechnology

Nanotechnology M. Juliantara

13.01.012.011Teknik MesinTugas Akhir mata kuliah Nanoteknologi

IntroductionThe Nature of Nanotechnology

Definitions of nanotechnology are easy to find, but hard to agree on. Most of literature simply say

that nanotechnology considers materials and architectures on the nanoscale

In some of the definitions it is stated that nanotechnology dealings mainly with structures in the region between 1 and 100 nm.

In any case, the dimension plays the dominant role.

What is Nanotechnology?

“Nanoscience is the study of phenomena and

manipulation of materials at atomic,

molecular and macromolecular scales, where

properties differ significantly from those at a

larger scale. Nanotechnologies are the

design, characterization, production and

application of structures, devices and

systems by controlling shape and size at the

nanometre scale”

the definition given by the “Royal Society

and the Royal Academy of Engineering”

Why 100 Nanometers?The range of 1 to 100 always definition continually in the nanotechnology literature. For example, one of the most popular introductions to nanotechnology defines thatNanoscience as “the study of the fundamental principles of molecules and structures with at least one dimension roughly between 1 and 100 nm.”But just what is so special about 100 nm?Why not 10 nm? Or 1,000 nm?The answer is that under the 100-nm level, engineers begin to deal with

properties of materials that ordinary engineers can quietly forget about.

Most of the currently known nano-effects are still deeply rooted in nanoscience, that is we cannot speak at all of a technology. A careful differentiation will be put forward, not just between science and technology, but also with the usual intermediate step, called (nano)engineering. The development of a technique from a scientific finding never happens in a single step.

From Nanoscience to Nanotechnology

Nanoscience, nanoengineering and nanotechnology are represented by three steps following each other. Each step contains several of very many possible examples, which will help to realize how nanoscience develops into nanotechnology.

Structured Surfaced

It has long been known that structured surfaces change the physical and chemical properties of the corresponding material. Two property changes dominate the interest in structured surfaces are: Change in wettability Change in optical properties

Technologies on the Nanoscales

Sketch of the gas–liquid–solid three-phase system.(a) Water droplet on a smooth surface resulting in small contact

angles y(b) On a nanostructured surface with increased y value(c) On a bimodal micro/nano structured surface with thelargest contact angle.

Since the 1980s a slew of new instruments and manufacturing processes have emerged that enable scientists and engineers to see that is, measure and manipulate at the nanolevel. It is because of these that nanoengineering is emerging as a commercial endeavor.

Nanotool and Nanomanufacturing

Top-down manufacturing processes Products are designed using macrolevel

materials. To put it perhaps a little crudely, one whittles away at the material until nano-level features can be achieved.

While the whittling process is, of course, as old, even perhaps older, as mankind, this process does not inherently produce nanoscale structures.

Its ability to do so depends on the material being used and especially on the tools being used. Much of the commercial nanotechnology today can be traced back to better tools that “sculpt” at the nanoscale.

Bottoms-up approaches products and materials are created one molecule at a

time. Nanotechnologists are practical people and must make

do with the current generation of manufacturing technology, which is not especially bottoms up in nature.

Also, manufacturing one molecule (or atom) at a time can sometimes be as painfully slow as it sounds, yet again another drag on the potential for real business opportunities.

Application of Nanotechnology

Photovoltaic Manufacturing

Nanotech & Energy

Nanotechnology Could make energy supply lean, green and mean

-Headline of the article on azanano.com website-

The energy industry has a crisis all its own, however, often presented as a shortage of energy. The portrayal is based primarily on the theory that much of our energy comes from fossil fuels and that we are quickly running out of those fuels.

Presenting the opportunities for nanotechnology in the energy sector as largely defined by supposedly dwindling petroleum reserves is likely to lead to an underestimation of the opportunities and perhaps to misunderstandings about what those opportunities actually are.

Instead, not so much that nanotechnology can help us provide new and better sources of energy, although, in fact, this is the case, but rather that nanotechnology can provide us with new ways to concentrate energy and deliver it to the places where it is needed are the key word.

Scientific View

Nanotech & Energy

Position of Opurtunity in Value Chain

Likely Contribution of Nanotechnology

Extraction Nano-enabled enhancements can lead to reductions in the cost of extracting fuels from fossil deposits thereby increasing the available reserves.Nanocatalysts and Nano-enhanced drills are two areas where there is some obvious potential.Nanoengineering may also provide better ways of harnessing renewable energy sources, especially better materials for windmills, solar power collectors, etc.

Transformation It is all about generating useful power from raw energy, simply making more efficient/ less polluting hydrocarbon fuels from raw fuels using nanocatalysts, for example.Electricity appears to be the most useful form of power known and it is important to remember that its all about how to generate electricity.

Storage Electricity is stored in batteries and nanotechnology is certainly making contributions to enabling more efficient battery technology.

Nanotech & Energy

Position of Opurtunity in Value Chain

Likely Contribution of Nanotechnology

Distribution Long-haul transport of electricity is not outstandingly efficient and there is much room for improvement.Highly conductive nanomaterials, especially carbon nanotubes, offer hope for the future here.

Usage by Consumer

Nanomaterials can help in a number of ways to reduce the costs of energy at the consumer level.Better insulation using nanomaterials, Additives to fuel oil that make them produce more energy per unit volume or mass, High-efficiency heating systems using nanomaterials is yet another.Nanosensors could also play an important role in conserving energy in buildings, by providing finely tuned power monitoring and control.

Impact Nanotechnology on Energy Sector

Based on the technology directions currently being taken by both R&D efforts and corporate commercialization programs, it seems reasonable to assume that the impact can be categorized into five reasonably well defined headings: The nano-enhanced fossil fuel sector Fuel cells and the nanoengineered hydrogen economy Nanosolar power The nano-enhanced electricity grid of the future Nanopower for the pervasive communications network

Nanosolar PowerLike fuel cells, solar power has been on the verge of solving our energy problems for a long time, but somehow has never managed to actually do so. This is because solar power fact that it based on inexpensive, but low energy density fuels, so by the time it is delivered to the customer they are quite expensive. The promise of nanotechnology in this cases is that it will make solar power much cheaper to do useful work.

Nanosolar PowerThere are actually (at least) Two possible ways in which people have proposed harnessing the power of the sun:

Passive solar Passive solar heating involves two main elements: south facing glass and a

thermal mass to absorb, store, and distribute heat. It seems possible that nanotechnology could make a contribution here with

better materials to improve both aspects of a passive solar power heating system.

Passive solar has proved quite effective, although it is not a system that can be easily retrofitted, because much of its effectiveness lies in the basic design of the home or other building.

Nanosolar Power

Photovoltaic (PV) systems Systems that come in various shapes and sizes that create

electricity through the photovoltaic effect, which is a physical phenomenon in which electrons are freed from materials by bombarding them with photons. In this case the photons are coming from the sun.

Photovoltaic systems have been around for quite some time and have found a number of niche applications, although they never seem to have lived up to the lofty expectations of some of their backers. Several companies are researching how nanoengineeredmaterials can reduce the cost of photovoltaic systems.

Photovoltaic (PV) System

As we have already know, the fuel for PV is free, but the capital costs of the PV system are high and the efficiencies are low, so to obtain large quantities of power a considerable amount of real estate is taken up with solar panels. As a result of these undeniable facts about solar, the prospects for solar energy have often been dismissed by analysts, who also note that the improvements in cost and efficiency of PV have not changed much in 30 years. Nanotechnology, however, may be able to waken PV from its slumber.

The current (at 2006) efficiency

of PV is about 15 percent, but

efficiencies of around 30 percent

have been seen in the lab for a

long time and by exploiting more

wavelengths available from the

sun, it is possible to push this

efficiency up past 60 percent. If

deployed commercially this

means that roughly one third of

the PV cells currently used would

now need to be used for a

particular application.

Photovoltaic (PV) System Mechanism of Generation

The solar cell is composed of a P-type semiconductor and an N-type semiconductor. Solar light hitting the cell produces two types of electrons, negatively and positively charged electrons in the semiconductors. Negatively charged (-) electrons gather around the N-type semiconductor while positively charged (+) electrons gather around the P-type semiconductor. When you connect loads such as a light bulb, electric current flows between the two electrodes.

Photovoltaic (PV) System Mechanism of GenerationVoltage and Current of PV cell ( I-V Curve )

Photovoltaic (PV) System Various Type of PVTypes and Convension Efficiensy of Solar Cell

Photovoltaic (PV) System Various Type of PV

Crystal cell (Single crystal

Poly crystalline Silicon)


Surface of PV cell


Use insolation efficiently and reduce

materials


Buried Contact Solar Cell

Photovoltaic (PV) System Fabrication Methode

How to make PV’s Silicon


Single Crystal Silicon Production Process


Poly Crystalline Silicon Production Process


From Ingot to Module


From Ingot to Module (Continue)


Belt Furnace

Photovoltaic (PV) System Installation

Solar Home System (SHS) as Example

Photovoltaic (PV) System The Characteristics

Adventages Clean

Solar energy is a clean energy. It emits very small

amount of carbon gases or sulfur oxides. Infinite

Solar energy is infinite and permanent.

Disadventages Volatile in output

The amount of sunlight varies according to seasons and weather. Therefore, generating electric power to meet the demand anytime is impossible. Low in power density

Regardless of the vast solar energy coming down to the earth, power density in sunlight can be as low as 1,000 watts/m2. Acquisition of vast amount of energy needs vast surface area of the solar cell.

Photovoltaic (PV) System Future Development

Advance Photon Management

Advances and improvements in efficiency involve materials that are applied externally to the cell, allowing them to be developed independently without impacting cell designs that are highly optimized. This decoupling is important because strategies and materials can be used in different technologies. Specific topics within this area, in order of increasing complexity are as follows.

Antireflection Coatings

Multi-layer or nanostructured antireflection coatings can extend photon collection both across the spectrum and at diffuse angles beyond normal incidence.

Increasing the Path Length through the Absorber.

Texturing, microstructures, or nanostructure-based on plasmonics divert photons coming normal to the surface to more oblique angles, increasing the path lengths of these photons through the absorber and, thus, the probability of absorption.

Optical field enhancement

Plasmonic enhancement of the optical field in the vicinity of a metal nanoparticle is used to increase optical absorption and hence carrier generation.


Downshifting

This is the process of converting high-energy UV and blue photons, and downconverting their energy to the middle of the visible spectrum where quantum efficiency values typically approach 100%.

Downconversion

Often called photon splitting, this is the process of transforming one high energy photon into two photons that still have sufficient energy to create electron-hole pairs.

Upconversion

This is the reverse process whereby two low energy photons are combined to produce one high energy photon that is capable of generating an electron-hole pair

These last two processes are a very long way from being practical, but provide perhaps the best opportunity to truly surpass the S-Q limit by altering the solar spectrum to produce a photon distribution that is more aligned with the requirements of a single junction device.


Can Glass be Replaced?

This is a simple but critical question. A detailed analysis of thin film manufacturing suggested that under optimal conditions manufacturing costs could be reduced. It is not realistic to expect costs to be any lower for any technology that requires the use of glass and a transparent conducting oxide. A low cost, light-weight alternative that provides the same level of transparency, protection, and thermal stability would be nothing short of revolutionary. A positive answer to this question is essential if technologies such as OPV and DSC are to become cost-competitive for principal power generation.