Graphene Oxide as an Additive in Liquid and Printable Electrolyte for Dye-sensitized Solar Cell Applications

Abstract

Graphene oxide (GO) was firstly synthesized from graphite via modified Hummers method Then it was exfoliated in distilled water and freeze-dried to obtain graphene oxide sponge (GOS) The obtained GOS has spongy foamy and porous structure compared to sheet-like GO The GOS was then applied as additive in liquid and quasi-solid electrolyte for dye-sensitized solar cell (DSSC) application The GOS-liquid electrolyte was then injected to DSSC devices meanwhile the GOS-quasi-solid electrolyte was printed onto photoelectrode active area by doctor blading The measurement of DSSC devices were performed under one sun illumination (AM 1 5G) For liquid electrolyte system devices containing 0 6 wt% GOS showed improved cell performance from 8 84% to 9 22% While for quasi-solid electrolyte system devices containing 1 5 wt% GOS showed improved cell performance from 8 12% to 8 78% The improvement of power conversion efficiency for both kind devices was mainly attributed to higher open circuit voltage (Voc) and fill factor (FF) Electrochemical impedance spectroscopy (EIS) analysis was carried out and it elucidated that GOS decreased the electron recombination rate leading to increased Voc The dark current also confirmed the decreased of dark current indicating that GOS suppressed the electron recombination As the DSSCs containing quasi-solid electrolyte were subjected for 500 h stability test at 60oC under dark both without and with additive maintained 79% and 84% of its initial efficiency while the DSSC with liquid electrolyte maintained only 42% of its initial efficiency

Date of Award	2017 Jan 23
Original language	English
Supervisor	Yuh-Lang Lee (Supervisor)