This course introduces solar cell and other technologies for low-carbon energy systems. It starts with a review of semiconductors, with a focus on the fundamentals for solar cell development. The content covers such as electron and hole, Fermi energy, generation and recombination, p-n junction, and the optical and optoelectronic properties. The course then elaborates the solar cell technology in-depth – covering (i) the basic principles of photovoltaic devices, including absorption, photo-electric conversion, conversion efficiency, loss mechanism, carrier collection and device characterization; (ii) the four generations of solar cell technology, e.g., monocrystalline solar cells, thin-film solar cells, dye-sensitized solar cells, organic solar cells; and (iii) other related engineering topics such as concentrated solar power, management techniques, manufacturing systems, reliability, life-cycle analysis, markets and policies. Beyond the solar cell technology, the course continues with discussions on other low-carbon energy technologies, for instance, thin-film transistors, ultralow-power flexible electronics, light-emitting diodes, and nanoenergy harvesting technologies. In the end, the course concludes with fabrication towards large-scale, low-cost and green manufacturing, including the key considerations in developing large-scale, flexible devices and the emerging printing techniques.
Review of Semiconductors:
- Basics: Semiconductor crystals, two types of current carriers in semiconductors: intrinsic and doped semiconductors, electron and hole generation and recombination in thermal equilibrium; modelling the diffusion: diffusion-current equation, continuity equation, and doping profiles; drift current.
- Carrier mobility: Effective mass, thermal velocity and drift velocity; mobility; scattering: dependence of mobility on temperature and doping concentration; mobility versus diffusion coefficient: Haynes-Shockley experiment and Einstein relationship.
- Energy-Band model: Energy bands – quantum mechanics background; the population of energy bands: Fermi-Dirac distribution and Fermi level; energy bands with the applied electric field. Solar cell technologies:
- Introduction to solar irradiation; basic principles of photovoltaics, theoretical efficiency limit, and light management; crystalline solar cells, thin-film solar cells, organic and nanostructure-based solar cells, material factors, device design and fabrication methods. Module design and manufacturing, solar panels, system components and building (or grid) integration, scaling, life cycle assessment, and cost. Low-carbon energy technologies beyond solar cells
- Technologies beyond solar cells, including thin-film transistors, flexible and wearable electronics, light-emitting diodes, and nanoenergy harvesting;
- Manufacturing: Materials and the fabrication considerations and methods for large-scale, low-cost and green manufacturing;
- Printed electronics: Printable electronic materials, inks and formulations, printing technologies, and printable applications.
By the end of the course, students should be able to
- Gain the fundamental knowledge and skills in understanding the operation principles of solar cells and other related low-carbon energy technologies,and note the scope and limitation of the solar cells and beyond technologies.
- Apply the learned knowledge and skills in solid state devices for analysis in various types of solar cells and devices and their basic functionalities, basic device characterization techniques, and advanced device fabrication methods.
- Understand the technological impact of low-carbon energy technologies to the society.
- Understand the basic physical principles and the engineering know-how of low-carbon energy technologies for further specialization in areas related to display technology, solid state lighting technology, photovoltaic technology.