A Study on the Fabrication and Thin Film Encapsulation of Polymer-Based Photovoltaic Cells
Date Issued
2007
Date
2007
Author(s)
Hsu, Szu-Yuan
DOI
en-US
Abstract
This study aims to develop thin-film encapsulation using atomic layer deposition (ALD) for polymer solar cells to improve their lifetime while minimizing encapsulation-induced deterioration. For polymer solar cells the lifetime is most often defined as the time it takes for the efficiency to reach half its initial or maximum value.4
To obtain reliable vehicles with which to study encapsulation, a fabrication process for P3HT/ PCBM bulk-heterojunction solar cells was established through optimizing the cell layout and the concentration of the P3HT/PCBM solution. The optimized process yielded reproducible cells with power conversion efficiency up to 3.74 %. Encapsulation-induced deterioration of the cells was eliminated by (1) minimizing the ALD process time by modifying the deposition conditions, (2) using a P3HT/PCBM ratio of 1:0.8 instead of 1:1, and (3) setting the ALD process temperature at an optimized value of 180ºC. The lifetime of the cells was improved from ~ 7 to ~ 76 hr by encapsulation with a 600Å-thick ALD Al2O3, which was further improved 255 hr by adding a layer of a UV-curable adhesive on top of the Al2O3 layer. Although the ALD encapsulation significantly improved the cell lifetime, it was inferior to the reference encapsulation method using a glass cover slide attached by the UV adhesive, which achieved a lifetime of about 895 hr. The ALD encapsulation will be improved in the following work by (1) using plasma etching to thoroughly remove the active materials outside the cell area to minimize residues-induced defects in the ALD films, (2) fine-tuning the ALD process to improve the quality of the films, and (3) stacking the ALD films and the adhesive into multilayer encapsulation, e.g., ALD/adhesive/ ALD.
Subjects
元件製備與薄膜封裝
atomic layer deposition
SDGs
Type
thesis
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