| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 100 === In this work, we demonstrated the self-assembled monolayers (SAMs) assisted improvement of the efficiency of a dye-sensitized solar cell (DSSC). SAMs with different functional group were modified in between the TiO2/Electrolyte and FTO/TiO2 junction inside the work electrode. The work function of TiO2 working electrode were alter by the fabrication of SAMs, the lower work function can lead to higher energy barrier when injecting the electron, prompting the increase of Voc .furthermore, positive dipole moment on TiO2 working electrode surface by SAMs modified can attract electrons to the electrode direction forward, increase the speed of electron hole filling, result in higher Jsc.And for the optimized results, 3CN SAM modified cell can lead to higher conversion efficiency because of lower work function, positive dipole moment on TiO2 and its surface, and sustain amount of dye adsorption, from ~7.6% to ~8%
For the FTO/TiO2 junction, the SAMs were passivated on FTO electrode prior to the TiO2 absorption layer was doctor- bladed on it and sintered at 500oC. Charge mobility through FTO/TiO2 with SAMs-assisted fabrication process were proven to be improved comparing to the pristine device interface without SAMs-assisted process. Minute investigation indicated that the extreme hydrophilic nature of SAMs fabricated on the FTO, helped the TiO2 initial layer to be more compact in nature, resulting a decrease of impedance in FTO/TiO2 junction, which facilitated higher electron mobility and helped to improve the light conversion efficiency.The highest improvement of the cell conversion efficiency was from ~7.7% to ~8.6% under AM1.5G (1 sun), which was 13% of enhancement.
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