Template method for fabricating interdigitate p-n heterojunction for organic solar cell
- PDF / 359,080 Bytes
- 5 Pages / 595.28 x 793.7 pts Page_size
- 82 Downloads / 145 Views
NANO EXPRESS
Open Access
Template method for fabricating interdigitate p-n heterojunction for organic solar cell Jianchen Hu1,2, Yasuhiro Shirai1,3, Liyuan Han3 and Yutaka Wakayama1,2*
Abstract Anodic aluminum oxide (AAO) templates are used to fabricate arrays of poly(3-hexylthiophene) (P3HT) pillars. This technique makes it possible to control the dimensions of the pillars, namely their diameters, intervals, and heights, on a tens-of-nanometer scale. These features are essential for enhancing carrier processes such as carrier generation, exciton diffusion, and carrier dissociation and transport. An interdigitated p-n junction between P3HT pillars and fullerene (C60) exhibits a photovoltaic effect. Although the device properties are still preliminary, the experimental results indicate that an AAO template is an effective tool with which to develop organic solar cells because highly regulated nanostructures can be produced on large areas exceeding 100 mm2. Keywords: Anodic aluminum oxide, P3TH pillars, P-n junction, Photovoltaic effect
Background Bulk heterojunction (BHJ) solar cells [1,2] are superior to single- [3] and double-layer cells [4]. The BHJ structure can be formed simply by mixing a donor and acceptor solution. This straightforward technique is advantageous in terms of increasing the donor/acceptor (D/A) interface, which provides the exciton dissociation sites. Meanwhile, a weak point as regards BHJs is that the pathways of the generated carriers are not ensured because of the random phase separation of the respective materials. To ensure exciton dissociation and carrier collection, continuous percolation pathways are required. An ideal structure would be an interdigitated interface, where the donor and acceptor phases are separate. The diameter and interspatial distance of the pillars should preferably be comparable to the diffusion length of the excitons, which is of the order of 10 nm. Then, the excitons can diffuse to the D/A interface during their lifetime [5]. Furthermore, the interdigitated structure must be aligned perpendicularly to connect with the electrodes so as to provide direct pathways for efficient charge transportation [6,7]. Meanwhile, the film thicknesses should be around 100 to 200 nm to absorb the incident * Correspondence: [email protected]. 1 International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan 2 Department of Chemistry and Biochemistry, Faculty of Engineering, Kyushu University, 1-1 Namiki, Tsukuba 305-0044, Japan Full list of author information is available at the end of the article
light and to confine the series resistance [8,9]. For these reasons, the dimensions of the interdigitated structures should be carefully designed to enhance photovoltaic effects. Interdigitated structures have been obtained using different techniques including self-organization and nanoimprinting [10,11]. However, there is still room for further optimization of the dimensions [12]. In this study,
Data Loading...
