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Wednesday 7 December 2016

Solar Energy Conversion Techniques//http://khawaja92.blogspot.com

Solar Energy Conversion Techniques
Photovoltaic
Overview of world energy, Options for harnessing solar energy  and their respective current and projected costs/potential, compared to traditional sources. Fundamentals of photoelectric conversion: charge excitation, conduction, separation, and collection. Commercial and emerging photovoltaic (PV) technologies. Cross-cutting themes in PV: conversion efficiencies, loss mechanisms, characterization, manufacturing, systems, reliability, life-cycle analysis, risk analysis. Photovoltaic technology evolution in the context of markets, policies, society, and environment.

Charge excitation and conduction
How light is converted to electricity. Direct and indirect semiconductor bandgaps. Optical properties of semiconductors. Introduction to intrinsic, doped semiconductors, conjugated polymers. Minority carrier mobility, lifetime, diffusion length. Charge excitation in non-semiconducting materials. Conduction, dispersive hopping. 

Charge separation
How voltage, current are formed. Minority-carrier devices: semiconductor pn-junctions. IV curves. Majority-carrier devices (organics). Quantum-size effects of charge separation.

Charge collection, and the solar cell device
Metallization. Solar cell device architectures. Common limitations of efficiency, short-circuit current, fill factor, open-circuit voltage.

Commercial technologies-I
Crystalline silicon solar cells, Crystal growth: ingot silicon, ribbon and sheet silicon. Wafering. Cell fabrication: methods, architectures, concepts. History, state-of-the-art. Emerging trends, cutting-edge technology. Role of innovation. 

Commercial technologies-II
Thin Films: thin film silicon (incl. amorphous, SiGe, micromorph, tandem cells), cadmium telluride, copper indium gallium diselenide. Precursors. Deposition processes and technologies. Other technologies: concentrator devices and materials, heterojunction devices, photovoltaic thermal.
emperature at surface the sun is about 6000K. 

Power density 5.961 × 107 W.m−2 at its surface the sun
Power density 1353 W.m−2 in Earth orbit, at distance of 150 × 106km 
Power density 1000 W.m−2 at the Earth’s surface. 

The exact figure for the solar power density depends on 
latitude, 
season, 
climatic conditions
and albedo of the surroundings. 

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