Browsing by Author "Zhao, Ni"

Now showing 1 - 2 of 2

High efficiency ternary organic solar cell with morphology-compatible polymers
(2017-06-21)
Mai, Jiangquan
;
Lu, Haipeng
;
Lau, Tsz-Ki
;
Peng, Shih-Hao
;
Hsu, Chain-Shu
Ternary organic solar cell is a promising strategy for improving the power conversion efficiency (PCE) of single-junction organic solar cells by broadening the light absorption spectrum with the incorporation of two electron donors and one acceptor or one donor and two acceptors. However, in many cases the optimized loading of the third component is so small that its contribution to the light absorption is limited. Following our previously proposed selection rule for the two polymers capable of comparable loadings, we report in this work a ternary system composed of two morphologically compatible polymers with distinct chemical structures that can achieve a high PCE of 9.0% with a mass ratio of 1:1. Besides the expected improvement in short circuit current due to the broadening of the absorption spectrum, the fill factor of the ternary device is improved significantly. We attribute it to the balanced electron and hole mobility and reduced recombination benefiting from the high morphology compatibility of the system.
Understanding Morphology Compatibility for High-Performance Ternary Organic Solar Cells
(2016-09-13)
Mai, Jiangquan
;
Lau, Tsz-Ki
;
Li, Jun
;
Peng, Shih-Hao
;
Hsu, Chain-Shu
Ternary organic solar cells are emerging as a promising strategy to enhance device power conversion efficiency by broadening the range of light absorption via the incorporation of additional light-absorbing components. However, how to find compatible materials that allow comparable loadings of each component remains a challenge. In this article, we focus on studying the donor polymer compatibilities in ternary systems from a morphological point of view. Four typical donor polymers with different chemical structures and absorption ranges were mutually combined to form six distinct ternary systems with fullerene derivative acceptors. Two compatible ternary systems were identified as showing significant improvements of efficiency from both binary control devices. Ternary morphologies were characterized by grazing incident X-ray scattering and correlated with device performance. We find that polymers that have strong lamellar interactions and relatively similar phase separation behaviors with the fullerene derivative are more likely to be compatible in ternary systems. This result provides guidance for polymer selection for future ternary organic solar cell research while relaxing the limitation of chemical structure similarity and greatly extends the donor candidate pool.