| Summary: | 碩士 === 龍華科技大學 === 機械工程系碩士班 === 102 === In this study, atmospheric chemical vapor deposition (APCVD) is employed to grow zinc oxide materials, for the purpose as electrodes in DSSC. Experimental results show that zinc oxide can be successfully deposited at temperature below 400℃, which is 200℃ lower, as compared with the deposition temperature needed in our LPCVD system, 600℃. It was suggested that at 1 atm, the collision frequency of reactants in gas phase is much higher, therby reduce the reaction barrier, and the deposition temperature. Several other parameters such as precursor sublimation temperature, dosage weight % of iron acetylacetonate, and chamber oxygen concentration have been examined, and used to evaluate the performance of CVD ZnO electrodes. As compared with other substrates like Si(100), or zinc oxide buffer layers, aluminum metal works better.According to SEM observations, most APCVD ZnO deposits are granular, rather than thin nanowires. It seems that the growth of ZnO follows Volmer Weber, or Island mode, which suggested that the contact angle is large. However, DSSC used CVD ZnO on aluminum as electrodes give the highest efficiency (η). In addition to this, APCVD ZnO performed at low oxygen concentration, [O2(g)] < 20%, and intermixed with 10 wt % iron acetylacetonate, will make the DSSC efficiency increase further.Acquired deposition results indicate that, if ZnO CVD was performed at process condition as: zinc acetylacetonate mixed with 10 wt% iron acetylacetonate, oxygen and helium flow rates at 10, and 50 sccm, respectively, a sublimation temoerature at 120℃, and deposition temperature at 350oC, the resulted DSSC may owns a current density of 0.19 mA/cm2, and energy conversion efficiency of 1.42%.X-Ray diffraction patterns imply that APCVD grown ZnO substances are polycrystals, with crystal orientations of ZnO(110), (002), (101), (102), and (110) been identified. Some have preferential orientations at (100), and (101).
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