SREELAKSHMI S S3 EC ROLL NO:55 QUANTUM DOTS SREELAKSHMI S S3 EC ROLL NO:55 QUANTUM DOTS

INTRODUCTION Quantum Dot (QD) is a nano crystal made of semiconductor materials that are small enough to exhibit quantum mechanical properties . Researchers have studied applications for QD in Transistors, Solar Cells, LEDs, and diode lasers . QUANTUM DOTS

WHAT ARE QUANTUM DOTS ...? QD was invented in 1983 by Brus as some small semiconductor spherical particle in colloidal suspension. QDs are semiconductor nanocrystals. They are made of the same ordinary semiconductor materials(combination of transition metals or metalloids). Unlike ordinary semiconductors, QDs are extremely small (usually 2-10nms).

COLOUR EMISSION BY QD

SYNTHESIS OF QD CHEMICAL SYNTHESIS The most accessible technique is colloidal synthesis - that is, chemically producing quantum dots suspended in solution. One method for producing CdSe is shown in Fig, but a variety of chemical synthesis routes are possible for each semiconductor material.

APPLICATIONS OF QD Medical Imaging and Diagnosis QDs can be useful for monitoring cancerous cells and providing a means to better understand its evolution. It can be used in tumour fighting toxic therapies. QDs are much more resistant to degradation than other optical imaging probes.

Quantum Dot LEDs Gives high peak brightness in LED TV. Gives better colour accuracy and colour saturation.

Solar cell and photovoltaic cell

ADVANTAGES OF QD They are water soluble substance. QDs as pH probes was found to be more convenient, rapid and specific method for kinetic studies.

DISADVANTAGES OF QD QD maybe toxic according to its composition which includes some heavy metals , and also the degradation of QDs is still unknown specifically inside the living organism

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