MATERIALS FOR ABSORPTION OF LIGHT AND

CONVERSION INTO HEAT OR ELECTRICAL

ENERGY

Zoran Karastojković1, Milesa Srećković2, Nikola Bajić3,

Zoran Janjušević4

Technical college, 11070 Novi Beograd, Blvd. Dr Zorana Đinđića152a, Serbia

Faculty of electrical engineering, 11000 Belgrade, blvd. KraljaAleksandra 73, Serbia

IHIS Technoexperts 11080 Belgrade, Batajnički put 23, Serbia,

Institute for technology of nuclear and other mineral raw materials, 11000 Belgrade, Franchѐt d'Esperey 86, Serbia,

Повод (spiritus movens) за овај рад

је посета Америци, тадашњег (пот)председника (?) Владе

Србије Ивице Дачића, у циљу производње чипова код

нас. Спомињале су се милијарде долара...

Споменути је завршио Факултет политичких наука, а ја

нисам регистровао да је неко са техничких факултета

или института реаговао на то.

Испада, па шта ће нам техника!

Па стварно, колико би уштедели ако би укинули техничке

факултете и остали само правни, економски и слични

менаџерски факултети?

SOME FACTS ABOUT ABSORPTION

Absorption represents one of the fundamental

properties related to the light beam. We used to speak

about absorption but we still dont know is it

absoprtion or adsorption; or about physical/chemical

nature of these processes.

Only if absorption is satisfied than conversion of light

beam energy, i.e. solar energy conversion, further may

take place.

Anyway, the absorption of light in a semiconductor

material represents a complex interaction of light with

the semiconductor atomic structure.

Analyticall expression of absorption intensity

of out coming beam as a function of distance (or thick x) is

defined by relatively simply relation:

I=I0 exp(-αx),

in which meanI0 – intensity of incident light beam, α – is linear

coefficient of absorption, characteristic for each material.

This general law does not represents a

concrete solution about describing the problem

of physical-chemical behavior between surface

of target material and light beam.

Reflection as a property has an opposite

meaning according to the absorption:

if reflection is high than absorption is small,

and vice versa.

So, the reflection may be considered as an

undesired property in usage of light energy

in power systems.

But, reflection could not be considered as an

undesired property in all cases, because there

are situations where the reflection is pre-

requisite for successful absorption, next figure:

in the cosmos, (also in our solar system)

principally are present: solid bodies,vacuum

and electromagnetic radiation

ALBERT EINSTAIN USED TO SAY: COSMOS HAS NO

BOUNDARIES, HUMAN STUPID TOO.Photons are essential for light, etc... A few people,

in some relation to Novi Sad, gave their contribution

to the understanding of photons, etc.

Many religions accepted that God

has created the Earth planet.

OK.

It seems that all other things

were

MADE IN CHINA.

The absorption of light (sunny) beam in

solar cell and its conversion in another

type of energy could be considered in two

main directions:

conversion in heat energy or

conversion in electric current.

In absorption, generally, the chemical bonds of the target material, play the vital role.

An array of solar cells converts the solar energy into a usable amount of direct current (DC) electricity, which further may be converted into alternating current (AC).

HOME SYSTEM FOR ABSORPTION

of sun light is used for sanitary water and floor

heating, when money is saving...

ONE PRACTICAL SOLUTION FOR ABSORPTION

OF LIGHT BEAMS for water heating by using sunlaight

is known from the stone age.

УВЕК ЈЕ БИЛО: КО ИМА ПАРА КУПА СЕ У МОРУ, А КО НЕМА

КУЋИ У ЛАВОРУ!

For absorption of sunlight beam energy usualy are

used pipes. Through the pipes (shown below) may

flow different materials such as: water, air, molten

salts, versatile (eutectic) alloys...

SYSTEMS FOR CONVERSION OF LIGHT BEAMS

INTO ELECTRIC CURRENT

Effect of sun beams on vegetable a) and how cell works b)

Solar cells can be made as one single layer

(single-junction) or multi-junctions. Many solar

cells make a photovoltaic (PV) system, Fig.6b).

Solar panels mounted on house roofs c)

and solar cells in space sattelite d)

MATERIALS FOR CONVERSION OF SUN

RADIATION INTO HEAT

Common materials as steel, copper and others, used for

direct heating up at the sun radiation, show pretty low

efficiency.

More effective materials for absorption, i.e. collecting

and conversion into heat energy, were on: graphite

base, TiC, TiO2, WO2, black chrome, even plastics,

Al-AlN cermet, CuO nanofluid, etc.

MATERIALS FOR CONVERSION OF SUN RADIATION

INTO ELECTRIC CURRENT

four generation are differentiated:

First generation

Monocrystals of silicon (c-Si)

Second generation

Amorphous silicon (a-Si)

Polycrystal silicon (poly-Si)

Cadmiumtelurid (CdTe)

CopperIndiumGaliumdiSelenid (CuInGaSe2) alloy (CIGS)

Third generation

Nanocrystal solar cells

Photoelectrochemical cells (PEC)

Gräetzel cells

Polymer solar cells

Solar cells on dye base (DSSC)

Fourth generation

Hybrids: anorganic crystals in polymer matrix

Silicon

Silicon as a semiconductor is one from the first

material used for conversion of solar energy.

Silicon is appearing in various forms, from first and

second generation, as: Crystalline silicon (c-Si),

Monocrystalline silicon, Epitaxial silicon, Polycrystalline

silicon, Ribon silicon, Mono-like-multi-silicon and in a

form of Thin film.

Some examples from second generation

The most known compounds from second generation

are: GaAs single crystal, GaAlAs/GaAs tandem, InP,

etc. Inermetallic compounds on the copper base

belong to systems: CuInSe2, CuGaSe, CuInS2, Cu(In1-x,

Gax)Se2 et al, as material with satisfied efficiency.

БАШ МЕ ЖИВО ИНТЕРЕСУЈЕ КОЈЕ

ИНТЕРМЕТАЛНО ЈЕДИЊЕЊЕ ЈЕ

ПРЕФЕРИРАО ДАЧИЋ?

One solar cell made from intermetallic

compounds CdTe and CdS, in cross section is

shown in Fig. 7.

Solar cells with copper, indium, galium and selen

have profile as shown in Fig. 8a). Elementary cell

from one crystal which is composed from cheap

elements Cu, Sn, Zn and S is shown in Fig. 8b).

а) b)

c)

Some examples from third generation

It is now possible to replace the classical

solid-state junction device by the

contacting phase to the semiconductor by

an electrolyte, liquid, gel or solid, thereby

forming a photo-electrochemical cell.

Тhese offer very low cost fabrication.

Light-absorbing dye (није у питању фарбање!)

Charge separation takes place at the

interface via photo-induced electron

injection from the dye into the conduction

band of the solid.

Carriers are transported in the conduction

band of the semiconductor to the charge

collector, as first was explained by

Gräetzel, Fig. 9a).

After Gräetzel cell many forms were

advanced, with metalic or non-metalic

base-material.

One of the typical Dye-sensitized solar cell (DSSC) is on

ruthenium-metalorganic dye, Fig. 9b), but other metals as Co

may be found as a monolayer of light absorbing material.

a)

b)

Optical sensitizer molecule in TiO2 and

triiodide c) and DSSC with graphene d)

Special case represents a solar cell able

to work at day but at night, Fig. 10.

Organic solar cell and polymer solar cell(These cells also are consist from one electron donor and

one electron acceptor)

Organic solar cells and polymer solar cells are

built from thin films (typically 100nm) made from

an organic semiconductors, including polymers

such as polyphenylene vinylene and small-

molecule compounds like copper phthalocyanine

(a blue or green organic pigment) and carbon

fasteners and fullerene derivates.

Such cells could be beneficial for some applications

where mechanical flexibility, Fig. 11a), is important.

Some examples from fourth generation

Hybrid colar cells consist of anorganic crystal in polymer

matrix, one example is shown in Fig. 12.

Solar cells on basis of carbon nano-

particles/tubes

It seems that carbon nanotubes (CNT) is preferential to

particles. CNT may be used as either photo-induced excitation

carrier transport medium impurity within polymer-based

photovoltaic layer or as the photoactive (photon-electron

conversion) layer.

Solar cells made from hybrids or nanoparticles/tubes are

cheap material but exibit priperties inferior to those of bulk

silicon semiconductors.

Ultra thin layer of carbon nanotubes is shown

in Fig. 13a), in blue color, and more detailed

arrangement in Fig. 13b).

ABSORPTION COEFFICIENTS The absorption coefficient determines how far a light of a

particular wavelength can penetrate into a material before is

absorbed.

Како то раде други:

(па и ови не праве оклагије!)

ЗАХВАЛНОСТ

Само сунцу и Богу могу да захвалим на

изради овог рада, као и нашој глупости

- да довољно нисмо развијали ову

област.

Хвала!

THANKS!

e-mail: zoran.karastojkovic@gmail.com