LIGHT HARVESTING APPLICATIONS

Graphene Based Composites For Light Harvesting Applications

Table of Contents

INTRODUCTION3

1.1 Introduction to carbon allotropes:3

1.2 Introduction Of Graphene And Its Electronic Structure And Electronic Properties:6

1.3 Graphene (And Graphene Oxide) Preparation Methods:8

1.4 Graphene Oxide Surface Functionalisation Methods:10

1.5 Preparation Of Organic Or Inorganic Graphene Composites14

1.6 Light harvesting applications17

1.7 Graphene Interactions With Excited State Semiconductors19

1.8 Photocurrent And Photocatalytic Applications Of Graphene Composites22

1.9 Non-Volatile Memory Device And Application Of Graphene Composites25

1.10 Aims of the Thesis28

1.11 References:30

Chapter 1

Introduction

1.1 Introduction to carbon allotropes:

The allotropes of carbon are the different molecular configurations (allotropes) that pure carbon can take.

1.1.1 Diamond

Diamond is one of the best known allotropes of carbon, whose hardness and high dispersion of light make it useful for industrial applications and jewelry. Diamond is the hardest known natural mineral, making it an excellent abrasive and also means a diamond holds its polish extremely well and retains luster.

The market for industrial-grade diamonds operates much differently from its gem-grade counterpart. Industrial diamonds are valued mostly for their hardness and heat conductivity, making many of the gemological characteristics of diamond, including clarity and color, mostly irrelevant. This helps explain why 80% of mined diamonds (equal to about 100 million carats or 20,000 kg annually), unsuitable for use as gemstones and known as bort, are destined for industrial use. In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s; another 400 million carats (80,000 kg) of synthetic diamonds are produced annually for industrial use—nearly four times the mass of natural diamonds mined over the same period.

The dominant industrial use of diamond is in cutting, drilling, grinding, and polishing. Most uses of diamonds in these technologies do not require large diamonds; in fact, most diamonds that are gem-quality except for their small size, can find an industrial use. Diamonds are embedded in drill tips or saw blades, or ground into a powder for use in grinding and polishing applications. Specialized applications include use in laboratories as containment for high pressure experiments (see diamond anvil), high-performance bearings, and limited use in specialized windows.

With the continuing advances being made in the production of synthetic diamond, future applications are beginning to become feasible. Garnering much excitement is the possible use of diamond as a semiconductor suitable to build microchips from, or the use of diamond as a heat sink in electronics. Significant research efforts in Japan, Europe, and the United States are under way to capitalize on the potential offered by diamond's unique material properties, combined with increased quality and quantity of supply starting to become available from synthetic diamond manufacturers.

Each carbon atom in diamond is covalently bonded to four other carbons in a tetrahedron. These tetrahedrons together form a 3-dimensional network of puckered six-membered rings of atoms. This stable network of covalent bonds and the three dimensional arrangement of bonds that diamond is so strong.

1.1.2 Graphite

Graphite (named by Abraham Gottlob Werner in 1789, from the Greek ??afe??: "to draw/write", for its use in pencils) is one of the most common allotropes of ...