Photovoltaic Cells PDF

PHOTOVOLTAIC CELLS INTRODUCTION Photovoltaic Cell is an electronic device that captures solar energy and transforms it into electrical energy. It is made up of a semiconductor layer. The term "photovoltaic" originates from the combination of two words: "photo," which comes from the Greek word "phos,...

PHOTOVOLTAIC CELLS INTRODUCTION Photovoltaic Cell is an electronic device that captures solar energy and transforms it into electrical energy. It is made up of a semiconductor layer. The term "photovoltaic" originates from the combination of two words: "photo," which comes from the Greek word "phos," meaning light, and "voltaic," which is derived from the name of Alessandro Volta. A photovoltaic (PV) cell, commonly known as a solar cell, is a device that directly converts light energy into electrical energy through the photovoltaic effect. These cells usually operate in a reverse bias environment.  Groups of Photovoltaic cells are electrically configured into module,panel and arrays.  CONSTRUCTION OF PHOTOVOLTAIC CELLS The diagram above is a cross-section of a photovoltaic cell taken from a solar panel which is also a type of photovoltaic cell.  The cell consists of each a P-type and an N-type material and a PN junction diode sandwiched in between. This layer is responsible for trapping solar energy which converts into electricity. The N-type layer is also known as the first layer or the emitter layer. The P-type layer is the base layer and the intermediate layer between the two is the PN junction diode. The surface of the cell is covered by an anti-reflective material which traps the light energy and avoids any loss of energy. The bottom layer, the last one may completely be covered by the material in which the conductor is made up of. WORKING OF PV CELLS A photovoltaic cell works on the same principle as that of the diode, which is to allow the flow of electric current to flow in a single direction and resist the reversal of the same current, i.e, causing only forward bias current. When light is incident on the surface of a cell, it consists of photons which are absorbed by the semiconductor and electron-hole pairs are liberated to produce an external DC supply. In a solar cell, the junction area is much bigger than the photovoltaic cell because its main interest is the generation of power but for a photovoltaic cell the main purpose is the generation of electricity. If the incident energy (hv) is greater than the energy gap of that semiconductor material, these electron-hole pairs are generated at the depletion region of a diode. When this photon from external radiation hits the diode, these electron-hole pairs disrupt the neutrality of the conductor. If an external current path has been provided then the electrons flowing through the P-side travel towards the N- side,eventually generating a DC current and the magnitude of this electromotive force generated is directly proportional to the intensity of the incident radiation.  This is the working of a photovoltaic cell.  APPLICATIONS OF PV CELLS Photovoltaic cells can be used in numerous applications which are mentioned below Residential Solar Power: Photovoltaic cells are commonly used in residential buildings to generate electricity from sunlight. Solar panels installed on rooftops or in backyard arrays capture sunlight used to power household appliances and lightning Solar Power Plants: Photovoltaic cells are used in utility-scale solar power plants to generate large amounts of electricity for distribution to the grid. These solar farms consist of thousands of solar panels arranged over vast areas of land, providing clean and renewable energy Solar Water Pumping: Photovoltaic cells in power solar water pumping systems used for irrigation, livestock watering, and drinking water supply in rural and off-grid locations. Solar-Powered Transportation: Photovoltaic cells are utilized in solar-powered vehicles, including solar cars, bicycles, boats, and aircraft. Solar panels mounted on the vehicle’s surface capture sunlight and convert it into electricity to supplement or replace traditional fuel sources. Space Applications: Photovoltaic cells are extensively used in space exploration and satellite missions to generate electrical power for spacecraft and space stations. Portable Electronics and Charging Stations: Photovoltaic cells are integrated into portable electronic devices such as solar-powered chargers, backpacks, and lanterns. Portable Electronics and Charging Stations: Photovoltaic cells are integrated into portable electronic devices such as solar-powered chargers, backpacks, and lanterns.  ADVANTAGES OF PV CELLS They are environmentally sustainable and produce clean energy. They have minimal upkeep expenses. It is a readily accessible and renewable energy source. They can be utilized for longer periods of time and are less DISADVANTAGES OF PV CELLS The production is low during winters and on cloudy days. Installation and the initial cost of the materials are expensive. Space consumption is more.