Applied Physics of solar energy conversion（太阳能能量转换的应用物理）.pdfVIP

Applied Physics of solar energy conversion • Conventional solar cells, and how lazy thinking can slow you down • Some new ideas *************************************************************** • Our work on semiconductor quantum dots 1 The big picture • ~ 13x 1012 W (TW) energy production rate is currently used in the world. • ~ 3 TW energy production rate is currently needed to maintain our quality of life in the US. • Potential sources: fossil fuel, nuclear, geothermal, hydro, solar. • Issues – hydro: we’re using it all now – fossil fuel: CO2 release, limited supply, politics – nuclear: limited uranium, safety, waste, thermal pollution – geothermal: not enough energy – solar: new technologies needed, distributed source (large areas needed) • thermal, biomass, electric 2 How much solar energy is there? • In the US: 13 3 2 – ~10 m² x 10 W/m x2.4hrs/24hrs=1000TW average – US highway area is almost 0.2% of the total land area – covering 0.2% of the US land area with 50% cells yields 1 TW • higher efficiency is important – to produce this area over a period of 20 years, we must 2 manufacture 2000 km /year. – That’s a lot of stuff 3 3 -5 8 2 2 • PVC plastic wrap = 10 m /10 m=10 m =100km /year 3 Constraints on novel solar cells/panels 1) Due to the cost of the balance of systems, a solar cell of zero cost must exhibit efficiency greater than about 15% to be f