Materials for Solar Energy: Solar Cells

MATERIALS FOR SOLAR

ENERGY: SOLAR CELLS

ROBERTO MENDONÇA FARIA PRESIDENT OF Brazil-MRS (SBPMat)

Materials for Solar Energy: Solar Cells

Materials for Solar Energy: Solar Cells

The concentration of CO2 in Earth’s atmosphere (2011) is approximately 392 ppm

(parts per million) by volume, and rose by 2.0 ppm/yr during 2000–2009.

Materials for Solar Energy: Solar Cells

In 2008, 8.67 gigatonnes of carbon (31.8 gigatonnes

of CO2) were released from fossil fuels worldwide,

compared to 6.14 gigatonnes in 1990.

Materials for Solar Energy: Solar Cells

The Planet Today

Materials for Solar Energy: Solar Cells

Today, the scientific evidence indicates that GHGs emissions from burning

fossil fuels and other sources are causing rising Global Warming.

To worsen this scenario, the world population growth and the continuous

expansion of the individual energy consumption directly increase the amount

of GHGs emission.

Therefore, to maintain and to increase the access to energy services and to

satisfy crucial needs required from the modern society, it is urgent the

development of a sustainable global energy system to replace that of high

GHGs emissions and unhealthy air pollutants.

Solar energy generation is a renewable energy source that can play an

important role in the future to reduce the amount of CO2 emissions.

Why Solar Energy?

Materials for Solar Energy: Solar Cells

Environmental Advantages. Solar power production generates electricity

with a limited impact on the environment as compared to other forms of

electricity production.

Matching Peak Time Output with Peak Time Demand. Solar energy

can effectively supplement electricity supply from an electricity

transmission grid, such as when electricity demand peaks in the summer.

Modularity and Scalability. As the size and generating capacity of a

solar system are a function of the number of solar modules installed,

applications of solar technology are readily scalable and versatile.

Flexible Locations. Solar power production facilities can be installed at

the customer site which reduces required investments in production and

transportation infrastructure.

Why Solar Energy?

Materials for Solar Energy: Solar Cells

Solar Spectral Irradiance

Two standard terrestrial spectral distributions (ASTM G173-03): the direct spectrum and the global.

Materials for Solar Energy: Solar Cells

The total irradiance just above the Earth’s

atmosphere is estimated to be approximately

174,000 TW.

This is an amount of energy eight thousand

more than the entire global consumption of

energy in 2007.

(average energy consumption was 15 TW)

Materials for Solar Energy: Solar Cells

Average Daily Solar Radiation at the Earth’s Surface

Materials for Solar Energy: Solar Cells

How Does Solar Energy Create Electricity?

Photovoltaic Device (or Solar Cell) can be an intelligent response.

Materials for Solar Energy: Solar Cells

Equivalent circuit for a Solar Cell

I = Iph - ID

Materials for Solar Energy: Solar Cells

Current-Voltage characteristic of a solar cell

Materials for Solar Energy: Solar Cells

Photovoltaic Device or Solar Cell Operation Principle - pn junction

Materials for Solar Energy: Solar Cells

First generation Solar Cells: Homojunction (Crystalline Silicon, Amorphous Silicon, and GaAs)

Materials for Solar Energy: Solar Cells

Second generation Solar Cells: Heterojunction (CdTe, CIGS, and thin films of amorphous silicon)

CdTe – Cadmium telluride

CIGS - Copper indium gallium selenide

Materials for Solar Energy: Solar Cells

Third generation Solar Cells: Tandem Solar Cell

Materials for Solar Energy: Solar Cells

Third generation Solar Cells: Bulk-heterojunction (Organic semiconductors – very thin films)

P3HT – Poly(3-hexylthiophene)

PCBM - [6,6]-phenyl-C61-butyric acid methyl ester

P3HT PCBM

Materials for Solar Energy: Solar Cells

Third generation Solar Cells: Dye-sensitized cells

Materials for Solar Energy: Solar Cells

Third generation Solar Cells: Quantum dots

InAs quantum dots

Materials for Solar Energy: Solar Cells

SC Generations max Lifetime Costs per Wh Market

First generation 30 % Decades $ 1 - $2 Commercial

Second generation 20 % Decades $ 1 - $2 Near commercial

Third generation 8 % 20,000 hours ? In research

Materials for Solar Energy: Solar Cells

Cost efficiency analysis for first-, second-, and third-generation solar cell technologies.

Materials for Solar Energy: Solar Cells

PV efficiencies obtained for various materials and technologies

Materials for Solar Energy: Solar Cells

Current uses of PV solar panels

Materials for Solar Energy: Solar Cells

Solar-Photovoltaic Panels connected to the electricity grid

Residential

PV installations in houses and on buildings connected to the

electricity grid has grown in recent years. Some government, as

Germany and Japan, has subsidy programs to stimulate the use of

solar energy.

Materials for Solar Energy: Solar Cells

Industrial Solar energy can be an adequate solution for industrial applications, especially where power is required at remote locations. Because solar systems are highly reliable and require little maintenance, they are also ideal in distant or isolated places.

Solar-Photovoltaic Panels connected to the electricity grid

Materials for Solar Energy: Solar Cells

The concept of BIPV means more than just solar panels mounted on a roof. It is

about creating inherent element of the shell structure of the building which

works with general design concept whilst increases efficiency of the whole

structure. BIPV adds value not only to economic model of the building but also

to its architectural image.

Building-integrated photovoltaics (BIPV)

Materials for Solar Energy: Solar Cells

Solar Power Plants - Photovoltaics

There are several photovoltaic solar plants installed in different countries (50-200 MWp). In

2009, the global production reached more than 10 gigawatts (GW), but it represents a very

small fraction of the world total energy consumption (less than 0.1 %).

Materials for Solar Energy: Solar Cells

Photovoltaic Market

Materials for Solar Energy: Solar Cells

Challenges for Giga and Terawatts scale •Cost: prices must approach the cost of 4-12 cents per kWh; •Efficiency: combined with the fabrication and maintenance costs, the efficiency must be improved; •Lifetime: PV-produced electricity depends on how long the system continues to produce power at its rated level. The lifetime required to reach a cost equivalent to conventional electric power could be in the range 5-30 years; •Scalability: This has to do with elemental abundance as well as the ability to process the materials quickly.

• Energy storage

Materials for Solar Energy: Solar Cells

THANK YOU