1

Functional Inorganic Materials

Prof. Dr.-Ing. habil. Mady Elbahri

Functional Inorganic Materials

CHEM-E4215 (5 cr)

Lectures (12 x): Monday 12.15 – 14.00

Thursday 14.15 – 16.00

Lecture Hall B 202b

Lecturers: Mady Elbahri (4 Lec.)

Antti Karttunen (4 Lec.)

Maarit Karppinen (4 Lec.)

MARKING

Exam 40 points: min. 15 p

Lecture Exercises 24 points:12 x 2 p; min. 15 p

Learning Diary 36 points:12 x 3 p; min. 20 p

The course provides/covers/focuses:

insights into various important/new functional inorganic

material families

applications related to e.g. new sustainable energy

technologies, optics, spintronics & other emerging fields

e.g. Low emissive coating, solar absorber,

superconductive, magnetic, ferroelectric, thermoelectric,

Li-ion and oxide-ion conductive & photoactive materials

physical phenomena behind the targeted material

functions

Lectures: 12 x ca. 2.5 h

Home problem solving 40 h

Independent homework 60 h

Exam 3 h

Learning Diary

Main purpose of the learning diary is to help you to deepen your understanding of

the subject and become more reflective of your own learning process

Do not try to re-write the lecture, or use the learning diary as a notebook

Write a short one page summary of the lecture topic and try to answer the

following questions:

- What was known and familiar to you beforehand ?

- What did you learn ?

- What remained unclear ?

Total length of the learning diary for the whole course should be appr. 20 pages

An important part of the learning diary is the last paragraph, where you should reflect

on the whole course, and especially on your own learning process!

- How well did you learn the topics ?

- Did your learning process change during the course ?

- Did your expectations of the subject matter change during the course ?

- What grade would you give yourself ?

Also remember that your learning diary provides a large part of the basis for grading

the course, so you should compile it carefully so that the teacher can assess your

learning process from it

Functional Inorganic MaterialsFall 2017

4

# Date Who Topic

1 30.10. Mady Metal-based energy-saving applications

2 2.11. Mady Metal-based energy-efficient windows and solar absorbers

3 6.11. Mady Metal oxides for energy-saving applications: Past and new trends

4 9.11. Mady Materials design and new perspectives

5 13.11. Antti Thermal conductivity

6 16.11. Antti Thermoelectricity

7 20.11. Antti Ferro-, pyro-, and piezoelectricity

8 23.11. Antti Magnetic and multiferroic oxides

9 27.11. Maarit Superconducting oxides

10 30.11. Maarit Ion conductivity: Oxygen

11 4.12. Maarit Ion conductivity: Lithium

12 7.12. Maarit Hybrid materials

Mondays: 12.15 - 14.00Thursdays: 14.15 - 16.00Lecture Room: B202b

Overview of lectures 1-4

5

# Date Who Topic and keywords

1 30.10. Mady Metal-based energy-saving applicationsKeywords: Concept/Terminologies, Energy-efficient Windows (Low e coating)

2 2.11. Mady Metal-based energy-saving applicationsNew prespectives & Nanocomposites

3 6.11. Mady Metal oxides for energy-saving applications: Past and new trendsOverview in Glazing, Functional Materials

4 9.11. Mady Materials design for Solar absorberTradtional design and new prespectives.

http://multimedia.3m.com 6

Energy Saving Solar Materials

Materials Design > Highly Transparent low-e Coating or Highly Absorber Films to

Enable Low-Energy Cost.

7

Darmstadt University of Technology in Germany won the 2007 Solar Decathlon in Washington, D.C. with this passive house.

Passive houseControlling the Solar-Matter Interactions

http://inhabitat.com/how-to-find-the-right-window-treatments-to-save-energy-and-money/

Energy Saving House

8

Total solar transmittance ( Tsol , expressed as a percent or a number between 0 and 1)

is the ratio of the total solar energy in the solar spectrum (wavelength 300–3000 nm of the

solar spectrum) that is allowed to pass through a (glazing) system, to the amount of total

solar energy falling on it.

Total solar reflectance (Rsol , expressed usually as a percent or a number between 0

and 1) is the ratio of the total solar energy that is reflected outward by the system to the

amount of total solar energy falling on it.

Total solar absorption or absorptance (Asol, expressed usually as a percent or a number

between 0 and 1) is the ratio of the total solar energy absorbed by a system to the amount

of total solar energy falling on it.

Solar-Matter Interactions

Energy Conservation

9

The solar irradiation consists of two components:

Direct irradiation is the solar radiation coming

directly from the sun to the point of observation

without scattering or absorption from the

molecules and particles of the atmosphere.

Diffuse irradiation is the irradiation received after

it has been scattered by these molecules

and particles (e.g. cloudy day, winter).

Solar Irradiation

10

Solar irradiance is the power per unit area received from the Sun in the form of

electromagnetic radiation in the wavelength range of the measuring instrument.

Solar radiation is peaked at visible.

https://en.wikipedia.org/wiki/Solar_irradiance

11

Luminous

f(λ) being the relative sensitivity of the human eye in the photopic state,T(λ) the transmittance spectrum of a system.

Similarly, we can also define the luminous reflectance and luminous absorption .

Luminous transmittance ( Tlum) is in effect the visible transmittance weighed

by the human eye sensitivity.

12

It describes the average spectral sensitivity of human visual perception of brightness.

Photopic : everyday light level luminosity functions

Scotopic : low light level luminosity functions

Luminosity Function

PhotopicScotopic

Mesopic vision is a combination of photopic vision and scotopic vision in low but not

quite dark lighting situations.

Photopic vision facilitates excellent color discrimination ability, whereas colors are indiscriminable under scotopic vision.

Use low-e coatings; heat is reflected back into the room during the

Use low-e coatings; heat is reflected back to the outside during the

Energy-efficient Windows

Double glazing units filled with inert argon.

14

Energy Saving House

ObjectiveSelectivity /Visible

Controlled Emmissivity / NIR

Switchability

http://inhabitat.com/how-to-find-the-right-window-treatments-to-save-energy-and-money/

15Brian A. Korgel, Nature 500, 278–279 (2013)

Which type of solar irradiation should comes into your house?

we can have huge thermal losses through them in cold climates (winter case) and undesired heat gains in hot

climates, especially if they receive direct solar radiation (summer case).

Smart Windows

16

Spectrally selective coatings are optically designed to reflect particular wavelengths, but

remain transparent to others. Such coatings are commonly used to reflect the infrared (heat)

portion of the solar spectrum while admitting more visible light.

Spectrally Selective Coatings

Note that for windows with different films on the two sides the reflectance will

depend on the side of the window surface exposed to the sun.

The term 'albedo' describes the proportion

of incident radiation reflected by a system.

A perfect reflector would have an albedo of 1,

whereas a perfect absorber would have an

albedo of 0.

17

Low-e (emissive) coatings are thin films that

exhibit spectral selectivity: they are highly

transparent in the visible (VIS) part of the

electromagnetic spectrum (from 0.4 to 0.7 μm),

highly reflective in the IR (for wavelengths higher

than 0.7 μm), and absorbing in the UV (e.g.,

below 0.4 μm).

Low-e (emissive) coatings

18

Visible transmittance (VT) is a fraction of the visible

spectrum of sunlight (380 to 720 nanometers), weighted

by the sensitivity of the human eye.

U-factor is the rate at which a window

conducts non-solar heat flow.

Solar heat gain (SHG) in general refers to the

heat increase of a structure (or object) in a space

that results from absorbed solar radiation.

Light-to-solar gain (LSG) It provides a gauge of

the relative efficiency of different glass or

glazing types in transmitting daylight

while blocking heat gains.

http://buildingcapacity.typepad.com/blog/2011/09/window-retrofit-dilemma-low-e-or-no-low-e-alistair-jackson-csba-leed-for-homes-ap-responds.html

Common Terminologies in the low-e Field

19

Type of Solar Gain & Low e

http://www.commercialwindows.org/lowe.php

20

During the winter, heat (long wave radiation) in the room naturally wants to

escape through the glass, but low-E glass reflects it back into the room keeping it

warm. If you touch a standard pane of glass in the winter it feels very cold, even

if the room itself is hot. If you touch the inner pane of Low-E glass, it feels

much much warmer.

During the summer months it is hot outside, but the low-E glass does not let

the infrared thermal radiation (long wave) pass through it reducing the overall

solar heat gain of the building. http://www.reuk.co.uk/wordpress/energy-efficiency/low-e-double-glazing/

How Does Low-e Glass Work

21

There are two types of Low-E Glass – Hard Coat and Soft Coat.

How is Low-E Glass Manufactured

Hard Coat Low-E glass (Pyrolytic)

has a thin layer of molten tin poured over it while

the glass is still slightly molten. The tin welds to

the glass making the coating very strong and

difficult to scratch or remove.

Soft Coat Low-E glass ( Sputtering)

has silver, zinc, or tin applied to it in a vacuum

chamber filled with an electrically charged inert

gas. Atoms of the coating metal are sputtered

onto the surface of the glass where they stick.

Soft Coat Low-E glass has better insulating qualities than Hard Coat Low-

E glass. In double glazing units filled with inert argon, the R value (measure of resistance to heat loss) is 4.35 for soft coat, and

2.75 for hard coat. A single pane of regular glass would have an R

value of below 1.

22

Sputtering is a technique used to deposit thin films of a material onto a surface ("substrate").

1) creating a gaseous plasma (forth state of matter)

and then accelerating the ions from this

plasma into some source material (a.k.a. "target")

2) the source material is eroded by the arriving

ions via energy transfer and is ejected in the form

of neutral particles - either individual atoms,

clusters of atoms or molecules.

3) As these neutral particles are ejected they will travel

in a straight line unless they come into contact with

something - other particles or a nearby surface.

4) If a "substrate" such as a Si wafer is placed in the path

of these ejected particles it will be coated by a

thin film of the source material.

23

Adsorption Process

24

Basic modes of thin film growth:

(a) island in the Volmer-Weber mode, 3D Volmer-Weber mode: separated islands form on the surface of substrates,

in which the interaction between atoms of film is greater than that between a

substrate and the adjacent atoms of film.

(b) layer by layer in the two-dimensional Frank-

van der Merwe mode, 2D Frank-van der Merwe mode: layer-by-layer growth, in which the

interaction between substrate and atoms of film is greater than that between

adjacent atoms of film.

(c) layer plus island in the Stranski-Krastanov

mode. layer plus island, in which one or two monolayers form first and then grow

individually.By Phuoc Huu Le and Chih Wei Luo DOI: 10.5772/65898

Thin Film Growth

25

Typical transparent low-E coating materials

26

There is a relationship between emissivity e and conductivity s at frequency

The higher conductivity, the lower the emissivity

There is an estimation relationship between emissivity e and sheet resistance R

There are two type of materials for transparent low emissivity coating

Semiconductive coating, i.e. ITO, FTO

the extinction coefficient k is very small such as 0.01 at 550nm, so that typical thickness is

Micrometer with acceptable absorptions

Metallic coating, i.e. Ag and Au

the extinction coefficient k is very high such as 3.5 at 550nm, so that typical thickness is below

20nm for acceptable absorptions

Type of Low e Materials

27

28

Reflectivity as function of wavelength

Metal is a perfect reflector BUT how it can be used as a Transparent Low e

Coating?

29

Transparent Gold

30

Lecture assignment

What does spectrally selective coating means and

what it is impact on the Solar Heat Gain

Coefficient (SHGC)?

Describes the following terms:

a) Total solar reflectance b) 'albedo'

Best regards,

Mady