Browsing by Author "Sun, Shih-Sheng"

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Hydrogen Bonding-Induced H-Aggregation for Fluorescence Turn-On of the GFP Chromophore: Supramolecular Structural Rigidity
(1970-01-01)
Tsai, Meng-Shiue
;
Tsai, Sung-Yu
;
Huang, Yi-Fan
;
Wang, Chien-Lung
;
Sun, Shih-Sheng
To turn on the fluorescence of the native green fluorescence protein (GFP) chromophore, 4-hydroxybenzylidene-dimethylimidazolinone (HBDI), in an artificial supramolecular system has been a challenging task, because it requires high local environmental rigidity. This work shows that the formation of H-aggregates of an HBDI-containing organogelator results in two orders of magnitude fluorescence enhancement (phi(f)=2.9 vs. 0.02 %), in which the inter-HBDI OH...OH H-bonds play a crucial role. The aggregation-induced fluorescence enhancement of HBDI has important implications on the origin of the high fluorescence quantum efficiency of HBDI in the GFP beta-barrel and on the supramolecular strategy for a full fluorescence recovery of HBDI. These results reveal a new approach to designing rigid chromophore aggregates for high-performance optoelectronic properties.
New Helicene-Type Hole-Transporting Molecules for High-Performance and Durable Perovskite Solar Cells
(2018-12-05)
Lin, Yeo-Sin
;
Abate, Seid Yimer
;
Lai, Kuan-Wen
;
Chu, Chih-Wei
;
Lin, Yan-Duo
Three azahelicene derivatives with electron-rich bis(4-methoxyphenyl)amino or bis(p-methoxyphenyl)aminophenyl groups at the terminals were deliberately designed, synthesized, and characterized as hole-transporting materials (HTMs) for perovskite solar cells (PSCs). Optical and thermal properties, energy level alignments, film morphologies, hole extraction ability, and hole mobility were studied in detail. PSCs using the newly synthesized molecules as HTMs were fabricated. A maximum power conversion efficiency (PCE) of 17.34% was observed for the bis(p-methoxyphenyl)amino-substituted derivative (SY1) and 16.10% for the bis(p-methoxyphenyeaminophenyl-substituted derivative (SY2). Longer-chain substituent such as hexyloxy group greatly diminishes the efficiency. In addition, the dopant-free devices fabricated with SY1 as the HTM shows an average PCE of 12.13%, which is significantly higher than that of spiro-OMeTAD (7.61%). The ambient long-term stability test revealed that after 500 h, the devices prepared from SY1 and SY2 retained more than 96% of its initial performance, which is much improved than the reference device with standard spiro-OMeTAD as the HTM under the same conditions. Detailed material cost analysis reveals that the material cost for SY1 is less than 8% of that for spiro-OMeTAD. These results provide a useful direction for designing a new class of HTMs to prepare highly efficient and more durable PSCs.