Effects Of Amount And Wavelength Of Light On A Solar Cell

ABSTRACT

Solar cells, also called photovoltaic or PV cells, change sunlight directly to electricity. When sunlight strikes the solar cell, electrons are knocked loose. They move toward the treated front surface.

Solar cells generate an electrical current when light hits their surface. White light that we see from the Sun includes all colors of the visible spectrum and ranges in wavelength from about 400 nanometers (nm) to about 780 nm. Solar cells vary in their response to different wavelengths, or color, of light.

The objective of this work is to demonstrate how a solar cell responds differently to different wavelengths of light. You will develop this idea by covering the solar cell with color light filters and observing any changes in solar cell amperage output.

CHAPTER ONE

1.0                                                        INTRODUCTION

Photovoltaic materials have become a vital source of research and renewable energy in recent years as demand for energy increases.   Photovoltaic material may provide the solution to needs for energy as it may provide substantial amounts of renewable energy.  Photovoltaic materials were first discovered by a French physicist Edmond Becquerel around 1839, who was able to use sunlight to produce an electric current in a solid material.  Scientists began to truly understand this process in more than another century when they discovered that the photovoltaic effect caused certain materials to convert light energy into electrical energy at the atomic level.  Now, simple photovoltaic systems provide power in every day devices such as calculators and wristwatches.

One of the main factors that affect the efficiency of PV cells is the wavelength of light.  Light is composed of photons which range in wavelength.  As the light hits the surface of the PV cell, certain photons are reflected as opposed to being absorbed.

Traditional photovoltaic cells turn a relatively small part of the sun’s light spectrum into electricity, limiting their efficiency and power output. The cell’s silicon material responds to a limited range of light wavelengths, ignoring those that are longer and shorter. As the wavelength varies from short to long, the cell’s output rises and falls in a jagged curve. Newer photovoltaic cell designs achieve higher efficiency by converting more wavelengths into useful energy.

1.1                                     AIM AND OBJECTIVE OF THE STUDY

The objective is:

1. to develop a more efficient method of using light for solar energy, that is, to determine the effect of light wavelength on the electrical output of photovoltaic cells with the goal of improving the efficiency of solar panels.
2. To demonstrate how a solar cells responds differently to different wavelengths of light. You will develop this idea by covering the solar cell with color light filters and observing any changes in solar cell amperage output.

1.2                                           SIGNIFICANCE OF THE STUDY

Solar cells, also called photovoltaic or PV cells, change sunlight directly to electricity. When sunlight strikes the solar cell, electrons are knocked loose. They move toward the treated front surface. An electron imbalance is created between the front and back. When the two surfaces are joined a current of electricity travels between the negative and positive sides.

This study seeks to determine if exposure to specific light wavelength can improve the efficiency of photovoltaic cells.

1.3                                                 SCOPE OF THE PROJECT

The use of solar power as part of a portfolio of renewable energy technologies is a promising response to the world’s pressing energy challenges.  In this work, the effect of the color of light and load resistance on a solar PV panel and the wavelength of light received by the panel, as well as the electrical load present on the system were determined.  The voltage and current across the power load were measured in addition to the wavelength of the colors.

1.4              DEFINITION OF SOME TERMINOLOGIES USED IN THE STUDY

PHOTOVOLTAIC CELL (SOLAR PANEL):  A photovoltaic cell (PV cell) is a specialized semiconductor diode that converts visible light into direct current (DC). Some PV cells can also convert infrared (IR) or ultraviolet (UV) radiation into DC electricity.

WAVELENGTH:  Wavelength is the distance between identical points in the adjacent cycles of a waveform signal propogated in space or along a wire

PHOTOELECTRIC EFFECT: The photoelectric effect is the basic physical process by which a PV cell converts sunlight into electricity. When light shines on a PV cell, it may be reflected, absorbed, or pass right through. But only the absorbed light generates electricity.