High performance ZnO/organic hybrid solar cells consisting of graphene

• Main Authors: Yun-Ming Sung, 宋運明
• Other Authors: Yang-Fang Chen
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/27559068592815923516

碩士 === 國立臺灣大學 === 物理研究所 === 99 === At the time of high speed technology development, energy and environmental crisis, it is urgent to find effective and low-cost energy. Among all the recent researches for alternative energy, solar cell is one of the most noticeable devices. If we classify the type of solar cells, it can be discriminate as silicon solar cell, inorganic solar cell, dye sensitized solar cell and organic solar cell among of all these solar cells, the crystalline based solar cells have the highest efficiency. But, it still cannot become a major energy effectively because of its expensive manufacturing process and lacking economic benefits. In contrast, organic solar cells have a great advantage of low cost. It only needs a spin coater to fabricate the active layer and then annealed with a hotplate. According to its low cost, low temperature manufacturing process and easy thickness control, it would be practical to use them on flexible plastic board to make flexible solar cells. This thesis is mainly focused on the research of inorganic/organic hybrid solar cells. The inorganic/organic hybrid solar cells are made from ZnO rods and polymer P3HT/PCBM. After cleaning the ITO glass, ZnO rods were fabricated by the hydrothermal method, and then uniform P3HT/PCBM was spin coated on ZnO nano-rods. Finally, Ag electrode was evaporated for the measurement of photocurrent. The above-mentioned is called the standard device in this paper. We discover that distributing some graphene flakes on ZnO nanorod by spin coating graphene sol-gel before the fabrication of P3HT/PCBM layer can greatly improve the performance of solar cells by up to 100%. According to our study, the main reasons for the increased efficiency of solar cells can be attributed to large improvement in photocurrent and photovoltage caused by the direct electron path which is caused by functional graphene to form potential well on ZnO nanorod surface. As a result, charges can transfer from polymer blend to ZnO-nanorod more effectively and subsequently travel to electrodes leading to the improved performance in the photovoltaic devices.