Summary

Compared to traditional electrical filaments, arc lamps, and fluorescent lamps, solid-state lighting offers higher efficiency, reliability, and environmentally friendly technology. LED / solid-state lighting is poised to take over conventional lighting due to cost savings—there is pretty much no debate about this. In response to the recent activity in this field, Fundamentals of Solid-State Lighting: LEDs, OLEDs, and Their Applications in Illumination and Displays covers a range of solid-state devices, technologies, and materials used for lighting and displays. It also examines auxiliary but critical requirements of efficient applications, such as modeling, thermal management, reliability, and smart lighting.

The book discusses performance metrics of LEDs such as efficiency, efficacy, current–voltage characteristics, optical parameters like spectral distribution, color temperature, and beam angle before moving on to luminescence theory, injection luminescence, radiative and non-radiative recombination mechanisms, recombination rates, carrier lifetimes, and related topics. This lays down the groundwork for understanding LED operation. The book then discusses energy gaps, light emission, semiconductor material, special equipment, and laboratory facilities. It also covers production and applications of high-brightness LEDs (HBLEDs) and organic LEDs (OLEDs).

LEDs represent the landmark development in lighting since the invention of electric lighting, allowing us to create unique, low-energy lighting solutions, not to talk about their minor maintenance expenses. The rapid strides of LED lighting technology over the last few years have changed the dynamics of the global lighting market, and LEDs are expected to be the mainstream light source in the near future. In a nutshell, the book traces the advances in LEDs, OLEDs, and their applications, and presents an up-to-date and analytical perspective of the scenario for audiences of different backgrounds and interests.

Table of Contents

History and Basics of Lighting
Chronological History of Lighting
Learning Objectives
How Early Man Looked at the "Sun"
The Need for Artificial Light Sources
First Steps in the Evolution of Artificial Lighting
The First Solid-State Lighting Device
The First Practical Electrical Lighting Device
The Incandescent Filament Lamp
Mercury and Sodium Vapor Lamps
The Fluorescent Lamp
The Compact Fluorescent Lamp
Revolution in the World of Lighting: Advent of Light-Emitting Diodes
Birth of the First LED and the Initial Stages of LED Development
The Father of the LED: Holonyak Jr.
The Post-1962 Developments
Haitz’s Law
AlGaAs LEDs Grown on GaAs Substrates
AlGaInP LEDs on GaAs Substrates
Acquisition of Generated Light
The AlInGaN Material System: Blue and White LEDs
High-Power LEDs
LEDs and Materials Science
The Omnipresent Elements: Ga, N, and As
Further Refinements
Discussion and Conclusions
References
Review Exercises

Nature and Quality of Lighting
Learning Objectives
What is Light?
Vision
Opaqueness, Color, and Transparency of Materials to Light
Photometry
Colorimetry, Radiometry, and Photometry
Upcoming Colorimetric Metrics for Solid-State Lighting
Discussion and Conclusions
References
Review Exercises

Conventional Light Sources
Learning Objectives
Competing Light Sources
Incandescent Filament Bulb
Tungsten Halogen Lamp
High-Pressure Mercury Vapor Lamp
Metal Halide Lamp
Low-Pressure Sodium and High-Pressure Sodium Vapor Lamps
Fluorescent Tube and Compact Fluorescent Lamp
Performance Comparison of Different Traditional Light Sources
Discussion and Conclusions
References
Review Exercises

LED-Based Solid-State Lighting
Learning Objectives
LED Diode Family
LED Construction
Quasi-Monochromatic Nature of Emission
Red LED
White LED
Indicator- and Illuminator-Type LEDs
Preliminary Ideas of SSL
Why Solid-State Lighting?
Drawbacks of SSL
Potential and Promises of SSL
Discussion and Conclusions
References
Review Exercises

Inorganic LEDs
Physical Principles of Inorganic LEDs
Learning Objectives
Understanding Lighting Processes from Luminescence Theory
Injection Luminescence: The Most Efficient Electroluminescence
Mechanisms of Electron and Hole Recombination in Semiconductors
Recombination Rates of Excess Carriers and Excess-Carrier Lifetimes
Discussion and Conclusions
References
Review Exercises

Homojunction LEDs
Learning Objectives
Homojunction in Equilibrium
Reverse-Biased Homojunction
Forward-Biased Homojunction
Injection Efficiency of Homojunction LEDs
Discussion and Conclusions
References
Review Exercises

Heterojunction LEDs
Learning Objectives
Increasing Injection Efficiency in LEDs
Isotype and Anisotype Heterojunctions: Notational Conventions and Band Diagrams
Energy Band Offsets in Semiconductors
Advantages of Heterojunctions
Current Injection Ratio Estimation
Single Heterojunction LED
Double Heterojunction LED
Quantum Well Heterostructure LED
Comparison of Homo- and Heterojunction LEDs
Discussion and Conclusions
References
Review Exercises

Surface- and Edge-Emitting LEDs
Learning Objectives
LED Designs Based on Direction of Light Emission
Surface-Emitting LED
Edge-Emitting LED
Superluminescent LED
Discussion and Conclusions
References
Review Exercises

Light Extraction from LEDs
Learning Objectives
Total Internal Reflection of Light and the Escape Cone Concept
Techniques of Improving Light Extraction
Extraction Efficiency Formula for a Single-Escape Cone LED
Efficiency Enhancement by Making Nonplanar, Nonrectangular LEDs
Discussion and Conclusions
References
Review Exercises

Semiconductor Materials for Inorganic LEDs
Learning Objectives
Material Requirements for LED Fabrication
Common LED Materials
Discussion and Conclusions
References
Review Exercises

Fabrication of Inorganic LEDs
Learning Objectives
Heterostructure Growth Methods: LPE and MOCVD
LED Substrates
GaN Diode Processing Steps
Representative Process Sequences of GaN LED Fabrication
Discussion and Conclusions
References
Review Exercises

Packaging of LEDs
Learning Objectives
Through-Hole Packaging
SMT-Based Packaging
COB LED Packaging
Silicon LED Packaging
Heat Produced during LED Operation, and Reliability of LED Plastic Packages
Discussion and Conclusions
References
Review Exercises

LED Performance Parameters
Learning Objectives
Characteristic Parameters of LEDs
Current–Voltage Characteristics of LEDs
Current-Controlled Behavior of LEDs
Forward Voltage Drop (VF) across an LED
Reverse Breakdown Voltage (VR) of an LED
Efficacy of an LED, and the Difference between Efficacy and Efficiency
Optical Parameters of the LED
Discussion and Conclusions
References
Review Exercises

Thermal Management of LEDs
Learning Objectives
Short-Term Effects of Temperature on LED Performance
LED Lifetime Concept
Long-Term Influence of Temperature on Different Parts of the LED
Effect of Thermal Cycling on LED Performance
Correlation of LED Lifetime with Thermally Related Parameters
Maximizing Heat Loss from LED
Discussion and Conclusions
References
Review Exercises

White Inorganic LEDs
Learning Objectives
Primary, Secondary, and Complementary Colors
Wavelength Conversion and Color Mixing Techniques
Wavelength Conversion Examples
Color Mixing Examples
Relative Advantages and Disadvantages of White Light Realization Methods
Quality of White LED Emission
Discussion and Conclusions
References
Review Exercises

Phosphor Materials for LEDs
Learning Objectives
Nonusability of Traditional Phosphors in LEDs
Desirable Requirements for White LED Phosphors
Opportunities for LED Phosphors
Phosphor Location in LEDs
Phosphor Constitution
Phosphor Preparation
Types of Phosphors
Oxide Phosphors
Oxynitride Phosphors
Nitride Phosphors
Oxyhalides and Halide Phosphors
Sulfide Phosphors 288
Inorganic–Organic Hybrid Semiconductors as Phosphors
Organically Capped CdSe Quantum Dots and Sr3SiO5:Ce3+, Li+ Phosphors
Discussion and Conclusions
References
Review Exercises

High-Brightness LEDs
Learning Objectives
Defining High-Brightness LEDs
Necessity of High-Brightness LEDs
Number of Converters Required for Low- and High-Brightness LEDs
Lateral Structures of High-Brightness LEDs
Vertical Architecture of High-Brightness LEDs
Laser Lift-Off Process for Sapphire Substrate Removal
Heat Removal and Protection against Failure Modes
Colors of High-Brightness LEDs
Photonic Crystal LEDs
Encapsulant Materials for High-Brightness LEDs
Applications of High-Brightness LEDs
Discussion and Conclusions
References
Review Exercises

Organic LEDs
Organic Semiconductors and Small-Molecule LEDs
Learning Objectives
Organic Materials and Semiconductors
Electroluminescent Materials for OLEDs
Types of Organic Semiconductors
Early Organic Optoelectronic Materials and the First Organic LED
Energy Band Diagram of OLED
High-Efficiency OLED
Discussion and Conclusions
References
Review Exercises

Polymer LEDs
Learning Objectives
Moving to Polymers
Polymer LED Operation
Internal Quantum Efficiency of Polymer LED
Energy Band Diagrams of Different Polymer LED Structures
Fabrication of Polymer LED
Differences between Small-Molecule and Polymer LEDs
Organic LEDs, Inorganic LEDs, and LCDs
Discussion and Conclusions
References
Review Exercises

White Organic LEDs
Learning Objectives
Obtaining White Electroluminescence
Single Emitter-Based WOLED Schemes
Multiple Emitter-Based WOLEDs
Discussion and Conclusions
References
Review Exercises

LED Driving Circuits
DC Driving Circuits for LEDs
Learning Objectives
Features of DC Sources
Cell and Battery
Battery and Capacitor
Linear Transistor Regulator
Switch-Mode Power Supply
Buck Converter
Boost Converter
Buck–Boost Converter
LED Dimming
Lifetime of the Driving Circuit
Series and Parallel Strings of LEDs
Discussion and Conclusions
References
Review Exercises

AC Driving Circuits for LEDs
Learning Objectives
AC Mains Line
Rectification
Digital Methods of LED Driving
Analog Methods of LED Driving
Power Quality of AC-Driven LED Lighting
Power Factor of LED Circuits
Total Harmonic Distortion in LED Circuits
Resistor-Type and Buck Convertor LED Circuits
AC LEDs
Applications Requiring DC or AC LEDs
Capacitive Current Control LEDs
Discussion and Conclusions
References
Review Exercises

Applications of LEDs
LEDs in General Illumination
Learning Objectives
LED-Based Illumination
Retrofit LED Lamps
LED Bulbs
LED Tube Lights
LED Street Lights
LED Light Bars
Discussion and Conclusions
References
Review Exercises

Large-Area OLED Lighting
Learning Objectives
Paradigm Shift in Lighting Industry
OLED Tiles and Panels
Challenges of Large-Area Mass Manufacturing OLED Technology
Discussion and Conclusions
References
Review Exercises

Inorganic LED Displays
Learning Objectives
Definitions
Main Components of an LED Display
Types of LED Displays
Seven-Segment LED Displays
Resolution of LED Video Image
Virtual Pixel Method to Enhance Image Quality
Types of Virtual Pixels
Building Larger LED Screens by Assembly of Elementary Modules
Gamma Correction
Examples of LED Screens
LED Television (LED-Backlit LCD Television)
Flexible Inorganic LED Displays
Discussion and Conclusions
References
Review Exercises

Organic LED Displays
Learning Objectives
Evolution of Displays
Passive Matrix Organic LED Display
Active Matrix Organic LED Display
TFT Backplane Technologies
OLED Mobile Phone, TV, and Computer Displays
Discussion and Conclusions
References
Review Exercises

Miscellaneous Applications of Solid-State Lighting
Learning Objectives
Power Signage
Fiber Optic Communication Using LEDs
Wireless Communication with Infrared and Visible Light Using LEDs
Medical Applications of LEDs
LEDs in Horticulture
Discussion and Conclusions
References
Review Exercises

Smart Lighting
Learning Objectives
Infusing Intelligence or Smartness in Lighting Buildings
At the Planning Stage of a Building
Five Steps after the Building is Constructed
Aims and Scope of Smart Lighting Technology
Computer Networking
Programming Needs
Emergency Lighting
Smart Lighting Control System
Occupancy Sensing Devices
Daylight-Sensing Devices
Design Aspects
Night-Time Exterior Lighting
Discussion and Conclusions
References
Review Exercises

Future of Lighting
Opportunities and Challenges of Solid-State Lighting
Learning Objectives
Prospective Growth in Solid-State Lighting
Haitz and Tsao Predictions for the Years "2010–2020"
Research Areas and Technical Challenges
Moving beyond 2020
Discussion and Conclusions
References
Review Exercises

Laser Diode and Laser Diode-Based Lighting
Learning Objectives
Light-Emitting and Laser Diodes
Homojunction Laser Diode
Heterojunction Laser Diode
Carrier Confinement
Theory of Laser Diode
From LED to Laser Diode-Based Lighting
Discussion and Conclusions
References
Review Exercises
Index