太阳能电池发展现状与新一代光伏技术-上海交大沈文忠教授

Solar Cell Development Status and New Generation of PV Technology Institute of Solar Energy Shanghai Jiaotong University, Shanghai, China Prof. Shen Wenzhong Silicon solar cell has the highest convert efficiency in solar energy industry and is also with mature technology compare to other solar cell; therefore it plays the leading role in large scale application and mass production. In this paper, solar cell development status and new generation of PV technology will be discussed; at the same time, some bottlenecks and difficulties in silicon wafer R 效率 16-18%未来成本：预测晶硅电池组件可降到 $0.5～ 0.6/Wp; 效率 19-21%。这样可以导致光伏发电成本与常规发电成本相等甚至以下。晶体硅太阳电池十多年来一直是市场的主流 (80%以上 )，未来 10年应该也是！Fuhs et al., in 1974 proposed combining c-Si and hydrogenated amorphous silicon ( a-Si:H) to produce heterojuction (HJ) solar cells.Research groups in Japan innovate the design: inserting a thin intrinsic a-Si:H layer to passivate the defects of the surface of c-Si wafer between c-Si substrate and a-Si:H emitter.Low conversion efficiencyCalled “ HIT”(Heterojunction with Intrinsic Thin layer)HIT — new high efficiency cells双层膜异质结有机薄膜太阳电池1986年美籍华裔科学家邓青云博士率先实现， ~1-2% 的转换效率。先天缺陷：有机半导体介质厚度必须达到 100nm充分吸收太阳光，但这比激子扩散长度长了很多，激子在还没有充分地分离为载流子时，就已经复合了。年美籍华裔科学家邓青云博士率先实现， 的转换效率。先天缺陷：有机半导体介质厚度必须达到 充分吸收太阳光，但这比激子扩散长度长了很多，激子在还没有充分地分离为载流子时，就已经复合了。Appl. Phys. Lett. 48, 183 (1986); Nature 395, 257 (1998)Anisotropic alkaline texturization is a standard process for monocrystallineSi and is widely applied in present solar cell production. However, for polycrystalline Si, this method is not effective because only a fraction of the grains have the [100] crystallographic orientation.Si However, for polycrystalline Si, this method is not effectivePlanar Silicon Nanowire Array Solar CellsCoaxial Silicon Nanowire Solar CellsNature (London) 449, 885 (2007)respectively, by the built-in electric field.The photogenerated electrons and holes are swept into the n-shell and p-core, respectively, by the built-in electric field .Single-crystalline silicon nanowire p-cores were synthesized by means of a nanocluster-catalysedVLS method, and then chemical vapourdeposition was used to deposit i-and n-type nanocrystalline silicon shells.method, and then chemical vapour was used to deposit i-Silicon Nanowire Radial p-n Junction Solar CellsNano Lett. 10, 1082 (2010)This new method dramatically reduces surface roughness and improves control over the nanowire diameter and density, leading to greatly enhanced Voc, FF, and Jscvalues, ultimately yielding 10 times higher efficiencies using thin silicon absorber films.higher efficiencies using thin silicon absorber films.The 4.83% average efficiency for the 8μ m absorber silicon nanowire array solar cells is about 20% higher thanresults on 8μ m thick silicon ribbon solar cells, while the 20μ m absorber silicon nanowire cell average efficiency of 5.30%.μμsolar cells, while the 20μ等离子体陷光效应优点对快速发展的国际光伏市场非常重要，尤其是近年热门的 CdTe和 CIGS薄膜太阳电池，根据目前的发展情况到 2020年 Te和 In 的年需求量会超过现在的世界年产量，尤其是 In可能甚至会接近地球上目前探明的 In贮量。1. 等离子体光吸收增强方式有效减少光伏吸收层厚度 10-100倍，减少材料用量。对快速发展的国际光伏市场非常重要，尤其是近年热门的 和 薄膜太阳电池，根据目前的发展情况到 年 和 的年需求量会超过现在的世界年产量，尤其是 In可能甚至会接近地球上目前探明的 In 贮量。减少电池厚度可降低暗电流，使开路电路增加，从而使效率随厚度降低对数式升高，直到受制于表面复合。降低半导体吸收层厚度可以使载流子仅仅需要迁移较短距离而被捕获，从而可以使用少数载流子扩散长度较短的低质量多晶硅、量子点及有机半导体材料。2. 等离子体陷光效应可以提高太阳电池电学性能。减少电池厚度可降低暗电流，使开路电路增加，从而使效率随厚度降低对数式升高，直到受制于表面复合。3. 等离子体陷光效应降低材料质量的要求。降低半导体吸收层厚度可以使载流子仅仅需要迁移较短距离而被捕获，从而可以使用少数载流子扩散长度较短的低质量多晶硅、量子点及有机半导体材料。