| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 106 === Organic solar cells (OSCs) have been developed for several years due to clean energy source, low-cost manufacturing, and roll-to-roll solution production. In this thesis, we fabricated mechanically robust, stretchable OSCs by buckle-on-elastomer strategy and prepared stretchable electron selective layer (ESL) and non-fullerene photoactive layer to realize intrinsically stretchable organic photovoltaic devices.
Mechanically robust stretchable inverted organic solar cells via buckle-on-elastomer strategy (chapter 2): We fabricated an efficient, stretchable inverted organic solar cells by adopting a buckle-on-elastomer strategy, for which an ultrathin poly(ethylene naphthalate) (PEN) substrates coupled with a pre-strained (100 %) 3M elastomeric VHB 4905 tape was employed as the device substrate. Once the pre-strain was released, the formation of wrinkles accommodated further strain, which can afford the derived OSC with a much improved mechanically robustness and stretchability. As a result, we demonstrated a pristine OSC with the PCE of 5.61% using this method. The effects of mechanical deformation and durability on electrical performance were investigated. Compare to the pristine device, the PCE can remain its 74% efficiency under 30 % compression, and furthermore, can still retain its 64.3% efficiency after 50-cycle compression and stretching testing from 0 % to 30 % compression. This work proves that utilizing buckle-on-elastomer strategy can realize the stretchable organic photovoltaics with reasonably good mechanical duribility, which can become a potential for an ultrathin and lightweight power source.
Realization of intrinsically stretchable organic solar cells enabled by charge-selective layer and photoactive material engineering (chapter 3): We first fabricated a blend of PFN and NBR (Nipole®1072) as stretchable electron-selective layer. This PFN/NBR layer exhibited a much lower Derjaguin-Muller-Toporov (DMT) modulus (0.45 GPa) than the value (1.25 GPa) of the pristine PFN and could withstand a high strain (60% strain) without showing any cracks. Moreover, besides enriching the stretchability of PFN, the terminal carboxyl groups of NBR can ionize PFN to promote its solution processability in polar solvent and to ensure the interfacial dipole formation at the corresponding interface in the device, as evidenced by the FT-IR and UPS analyses. By further coupling the replacement of PCBM with non-fullerene acceptors owning better mechanical stretchability in the photoactive layer, OSCs with improved intrinsically stretchability and performance were demonstrated. An all-polymer OSC exhibited a PCE of 2.22% after 10% stretching, surpassing the PCBM-based device that can only withstand 5% strain. This work provides a universal strategy for the development of intrinsically stretchable organic photovoltaics.
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