Photovoltaic Solar Energy Conversion

Abstract

Sunlight consists of electromagnetic radiation in the regions ofultraviolet (UV), visible light, and infrared (IR) radiation. Thesolar spectrum reaching the earth’s surface undergoes variousabsorptions in the air atmosphere, and the average solar energyfalling on the earth’s surface is generally known as air-mass 1.5(AM1.5) irradiation, which is equal to approximately 100 mWcm−2. This quantity is equal to ∼1.0 kW of power falling on every square metre, which humankind has not yet effectively utilised. The shapeof the solar spectrum and the absorption of various wavelengthsunder AM1.5 conditions are shown in Fig. 1.1. Traditionally, thereare two ways of capturing solar energy. One method is to absorbmainly the heat energy (or IR radiation), and this is generally knownas ‘solar thermal technology’. The second method is to convertUV and visible light (photons) directly into electricity (measuredin volts). Since the photons are directly converted into volts, thismethod is known as ‘photovoltaic conversion’ (PV conversion forshort). This book concentrates only on the second method, whichis PV conversion.