| Summary: | 碩士 === 南台科技大學 === 光電工程系 === 101 === Organic solar cell (OSC) has been a highly potential solar cell technology due to their low cost, flexibility and scalability. In order to improve the power conversion efficiency (PCE) of OSCs, this study employs Rib-type surface textures on the front ITO electrode. This is to increase the light absorption area and enhance the light-trapping efficiency.
The Rib-type surface textures were fabricated by photolithography method . The Rib structure is in conical column pattern. The diameter and pitch of the Rib was changed. to qenerate pattern areas of 12.6%, 19.6%, 25.6% and 34.9%. The height of Rib texture varies from 0 to 4 μm. On top of the Rib textures, an ITO eayer as an anode was deposited by sputtering. This is followed by oxygen plasma treatment for ITO surface. Resistive thermal evaporations of 10 nm CuPc donor layer, 20 nm C60 acceptor layer and 15 nm BCP layer were then conducted. A 5 Å LiF buffer layer and a 150 nm Al cathode layer were finally coated. The complete OSC device has a structure of Glass ITO/Rib/ITO/CuPc/C60/BCP/LiF/Al. Results showed that the planar OSC has an optimal PCE when the a hole thickness of organic layers was increased by 10%. The PCE reaches 0.26% with Voc=0.45 V, Jsc=0.22 mA/cm2, FF=0.42. OSC devices with 90% Rib surface area were found to have larger Jsc than those with 65% area. This demonstrated that Rib textures could increase surface area and lead to an enhanced absorption efficiency. Howerer, PCE of OSCs with Rib textures is lower than that of planar devices. The main reason could be the deteriorated conductance of the sputtered ITO on Ribs.
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