Preface

This edited volume is a collection of reviewed and relevant research chapters concerning developments within luminescence technology and applications. It includes contributions by various authors and is edited by a group of experts in organic light-emitting diode (OLED) technology.

The book includes the following chapters:

Chapter 1: Luminescent Materials in Lighting, Display, Solar Cell, Sensing, and Biomedical Applications

Chapter 2: Triboluminescence: Materials, Properties, and Applications

Chapter 3: Mechanism of Photoluminescence in Erbium-Doped Chalcogenide

Chapter 4: Optically Clear Adhesives for OLED

Chapter 5: Picture Quality and Sound Quality of OLED TVs

Chapter 6: TADF Technology for Efficient Blue OLEDs: Status and Challenges from an Industrial Point of View

The target audience comprises scholars and specialists in the field.

**IntechOpen**

**1**

**Chapter 1**

**Abstract**

and biological applications.

**1. Introduction**

LEDs, solar cell, biological and clinical

**1.1 Luminescence in rare earth ions**

Luminescent Materials in Lighting,

Display, Solar Cell, Sensing, and

This chapter comprises a broader extent of the luminescence phenomenon with the mechanism involved therein as well as applications. Typically, the up and down conversion and downshifting behavior of the optical materials have been elucidated in brief. The fundamental understanding of these optical materials has been described by using schematic representations. It is well documented that the rare earth-based optical materials are known for their luminescent enrichment due to availability of the ladder-like energy levels. These energy levels can be utilized for the excitation of the luminescent materials by using a suitable excitation source. In the process of development of luminescent materials, choice of host matrices and dopant ions is very crucial. Strong correlation of these optical materials has been shown with the current scenario of our society and daily life. In view of the ongoing research, nanophosphor, glasses, and quantum dots with size- and shape-dependent optical behavior have been given in detail. The involved mechanism and the energy transfer phenomenon have been well elucidated by schematic and figures for the evident explanation to the readers. Our emphasis is to elucidate these optical materials in the development of innovative multifunctional applications such as lighting, display, sensing, LEDs, solar cell,

**Keywords:** light conversion, phosphor, quantum dots, optical temperature sensing,

In 1888, German physicist Wiedemann for the very first time employed the term "luminescenz." Luminescence promotes emission of light from a material at a certain excitation wavelength. It can be categorized into diverse kinds depending upon the various involved processes of excitation. It is classified as photoluminescence, thermoluminescence, electroluminescence, and chemiluminescence. Photoluminescence is a process in which the emission of light (photon) can be obtained from the object upon excitation. It is subgrouped into fluorescence and phosphorescence. In the thermoluminescence phenomenon, emission of light from a solid material occurs upon heating. Electroluminescence arises from gases under applied electrical potentials, while chemiluminescence may prevail during

Biomedical Applications

*Abhishek Kumar Soni and Bheeshma Pratap Singh*

## **Chapter 1**
