Study on photocurrent properties of organic hybrid solar cell based on poly(3-hexylthiophene) and TiO2 nanorods
Date Issued
2007
Date
2007
Author(s)
Lo, Hsi-Hsing
DOI
zh-TW
Abstract
Polymer-based solar cell has been fabricated by blending the conjugated polymer, poly (3-hexylthiophene) (P3HT) with TiO2 nanorods. Polythiophene and titania are frequently used as good electron donor and electron acceptor in organic solar cells, respectively, due to their good chemical stability, thermal stability and excellent charge transport properties. In our study, we tried to improve the power conversion efficiency of P3HT/TiO2 nanorods hybrid organic solar cell. Because device’s efficiency is determined by light harvesting, exciton dissociation and charge transport, so we tried to improve the efficiency of exciton dissociation and charge transport by studying the fundamental properties of active layer made from a solution consisted of conducting polymer and inorganic nanocrystal hybrid material. The effect of material properties on the photocurrent include hybrid composition, film thickness, polymer molecular weight, solvent type and ligand type.
For the influence of hybrid composition and active layer thickness on the device efficiency, the results showed that the device has better performance at 53 % by weight of TiO2 nanorods and at about 125 nm film thickness. For the effect of polymer molecular weight and solvent type in the hybrid on the device efficiency, we have found a high molecular weight polymer (~66 kD) and a medium volatile solvent of chlorobenzene provide best materials for high efficiency cell. The efficiency of exciton dissociation and charge transport in the device also can improve by surface modification of inorganic nanocrystal. We used pyridine, thienyl phosphonic acid and thienyl carboxylic acid to exchange oleic acid that capped on the surface of TiO2 nanorods. The results show the hybrid materials made of surface modified TiO2 nanorods exhibit better performance as compared to that of end-capped by oleic acid due to the improved surface interaction between polymer and nanocrystals.
The best performance devices was fabricated from a blend ratio of 47 to 53 by weight in P3HT to TiO2 nanorods, a film thickness of about 125 nm, chlorobenzene as a solvent, a P3HT molecular weight of 66kD, pyridine as a surfactant. The device exhibits power conversion efficiency, 0.7% under air mass 1.5 simulated solar illumination (100 mW/cm2).
Subjects
聚三己基噻
吩
二氧化鈦奈米桿
混掺
比例
膜厚
溶劑
界面活性劑
有機太陽能電池
poly (3-hexylthiophene)
TiO2 nanorods
hybrid ratio
active layer
thickness
solvent
molecular weight
ligand
organic solar cell
Type
thesis
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