| Summary: | 博士 === 國立臺灣大學 === 物理研究所 === 102 === Abstract
Recently, with the shortage of nature fossil, both scientific and industrial communities have devoted their efforts in developing renewable energy. Among the renewable resources, solar cells have been intensively studied nowadays. In this thesis, we report the improved efficiency of organic-inorganic hybrid solar cells, Si solar cells, and halide perovskite solar cells. With the organic-inorganic interface modification and using magnetic NWs as additive, we are able to improve organic matter arrangement, and thus enhance the efficiency of the devices. On the other hand, we use eco-friendly chlorophyll A to improve the efficiency of silicon based solar cells. Finally, a series of organic-inorganic halide perovskite solar cells with addition of spherical, rod Au nanostructures to the electron-transporting compact layer have been investigated. The highlight of our scientific achievement is briefly described as follows.
1. Effects of metal-free conjugated oligomer as a surface modifier in hybrid polymer/ZnO solar cells
The interface property has been one of the critical issues in developing hybrid polymer/metal oxide solar cells. We synthesize a conjugated oligomer, an amine-and bromine-terminated 3-hexyl thiophene (O3HT-(Br)NH2), to modify the ZnO-nanorod (ZnO-NR) surface in hybrid polymer/ZnO-NR photovoltaic cells. This oligomer is of the same repeat unit structure as and ~1/12 the contour length of the light-harvesting polymer. In addition to passivate the NR surface, the presence of this conjugated oligomer enhances the electron mobility, and drives larger hole density toward the anodic surface for collection. The improved charge transport property of the hybrid is presumably a result of modulating the nano morphology of the bi-carrier transport network induced by the conjugated oligomer. As a result, there is a large enhancement in photocurrent and photovoltage leading to an improved device performance of ~ 35%.
2. Magnetic-Field Annealing of Inverted Polymer:fullerene Hybrid Solar Cells with FePt Nanowires as Additive
We demonstrate a novel annealing method to improve the polymer chain ordering of poly(3-hexythiophene):(6,6)-phenyl C61 butyric acid methyl ester (P3HT:PCBM) blend triggered by a small amount of FePt nanowires (NWs). By applying a magnetic field (B-field) perpendicular to the substrate during the solvent drying process, the resulting P3HT:PCBM:FePt NWs film exhibits a relatively lower reflectance intensity in both in-plane and out-of-plane directions and becomes highly optical anisotropy with a preferential out-of-plane orientation. The improved polymer chain ordering revealed by the optical anisotropic measurements leads to more than 57% increment in the power conversion efficiency (PCE) of the devices. The method of magnetic-field assisted annealing is simple and can be applied to a wide variety of polymer blend systems. Additionally, it can be easily integrated into low-temperature and cost-effective fabrication processes, providing a new route for advancing flexible polymer solar cell development.
3. Improved light harvesting of surface textured Si solar cells using diatom extract
We demonstrate an effective approach to improve the light harvesting of silicon solar cells by incorporating the diatom extract as an antireflection coating. The diatom extract layer can suppress the overall light reflection up to 7% over spectrum regions of 350 – 1100 nm. Additionally, it also shows a strong photon downconversion effect within visible light regime. With both optical characteristics, the short circuit current is largely enhanced and hence the cell efficiency. The presented approach is simple, doable, suitable for large area application, and more importantly, it is eco-friendly.
4. Power conversion efficiency enhancement of organic-inorganic halide perovskite solar cells by addition of Au nanospheres and nanorods
We demonstrate a novel method to improve the organic-inorganic halide perovskite solar cells blend triggered by different morphologies amount of Au nanostructures. Addition of Au nanostructures with various morphologies into electron-transporting-layer of organic-inorganic halide perovskite solar cell increase the PCE as compared to the cell constructed without the addition of Au nanostructures. The increment is around 10% in the power conversion efficiency (PCE) of the devices. The method of fabricating organic-inorganic halide perovskite solar cells by sequential deposition and process of ZnO compact layer with low temperature is simple. Additionally, it can be easily integrated into low-temperature and cost-effective fabrication processes, providing a new route for advancing flexible organic-inorganic halide perovskite solar cell development.
|
|---|
