本論文主要研究利用超音波噴霧法製備低電阻率、高穿透度的FTO (氟摻雜的氧化錫)薄膜及探討不同霧度FTO膜對染料敏化太陽能電池(DSSC)效率表現影響。首先我們使用超音波噴霧熱解法來鍍FTO薄膜在玻璃基材上，並控制以下變因:(1)氟和錫的莫耳比 (2)溶液濃度 (3)鍍膜溫度 (4)間歇性鍍膜 (5)雙離子摻雜效應 (6)溶劑影響 (7)攜帶氣體。將所得到的FTO膜測定電性、光性、薄膜結構與表面形貌特性，得到以下結論。 FTO薄膜電阻率隨著摻雜氟濃度從0到0.4M的增加而從1.1x10-2 Ω cm減少到3.7x10-4 Ω cm，薄膜穿透度在摻雜氟濃度0.25 M之前隨著氟濃度增加而從46 % 降到43 % (500 nm)，然後隨摻雜氟濃度增加而增加。薄膜的載子濃度隨著氟濃度增加而從1.95 x1020增加到5.62 x1020 cm-3，而載子遷移率隨著氟濃度增加從3.83到29.10 cm2 V-1s-1。另一方面，由於FTO結晶經粒隨著鍍膜溫度的增加而變大，當鍍膜溫度增加從350 oC到450 oC，薄膜電阻率從4.5x10-3降低到5.8x10-4 Ωcm，而可見光穿透度則從66 % 略為到62 % (500nm)，同時薄膜的霧度隨著鍍膜溫度增加而增加。載子濃度隨著鍍膜溫度增加而減少從10.13 x1020到5.931 x1020 cm-3且遷移率隨著鍍膜溫度增加而增加從1.373到21.07 cm2V-1s-1。 在雙離子摻雜探討部分，薄膜電阻率隨著鋰濃度增加從0到0.07 M稍微從4.4x10-4增加到7.8x10-4 Ωcm，可見光穿透度則從62%到67% (500nm)。薄膜因鋰離子的摻雜降低了結晶粒徑因此霧度則隨著鋰濃度增加而降低。載子濃度與鋰濃度沒有明顯變化且載子遷移率則隨著鋰濃度增加而從29.63減少到24.23 cm2 V-1s-1。在攜帶氣體的影響方面，我們發現以氮氣作為攜帶氣體所製備之FTO電阻率為用空氣所製備的薄膜高出103倍，以氧氣為攜帶氣體則為空氣102倍，以空氣為攜帶氣體所製備的FTO薄膜其載子濃度和載子遷移率最高。最後我們控制FTO的製備步驟，調控出穿透度與面電阻值相近但霧度不同的FTO薄膜，以此FTO基板製備DSSC並比較其對元件效率的影響。結果發現使用較高霧度的FTO薄膜所製備的電池有較高的光電流與轉換效率。 In this study, it is focus on how to fabricate low resistivity and high transmittance FTO (fluorine doped tin oxide) thin films and study the effect of the haze of FTO on DSSC performance. At first, we deposit FTO thin films on the glass substrate by spray pyrolysis deposition method and control variables: (1) molar ratio of F/Sn (2) concentration of solute (3) deposition temperature (4) deposition steps (5) dual ion doping effect (6) solvent effect and (7) carrier gas. The optical, electrical, grain structural and surface morphological of FTO films are evaluated and we get some conclusions as below. The resistivity of FTO decreases from 1.1x10-2 to 3.7x10-4 Ωcm when fluorine concentration increases from 0 to 0.4 M. The transmittance decreases from 46% to 43% (500nm) when fluorine concentration reaches to 0.25 M. The carrier concentration increases from 1.95 x1020 to 5.62 x1020 cm-3 and the mobility increases from 3.83 to 29.10 cm2 V-1s-1 with fluorine concentration increase. As to the deposition temperature, the resistivity of FTO film decreases from 4.5x10-3 to 5.8x10-4 Ωcm and the visible transmittance decreases from 66% to 62% (500nm) when deposition temperature increases from 350 oC to 450 oC. The carrier concentration decreases from 10.13 x1020 to 5.93 x1020 cm-3 and the mobility increases from 1.37 to 21.07 cm2 V-1s-1 with the increase of deposition temperature. As to the dual ion doping effect (Li+ and F-), the resistivity of FTO film slightly increases from 4.4x10-4 to 7.8x10-4 Ωcm and the transmittance and haze of FTO film increase from 62% to 67% (500nm) with the increase of Li concentration from 0 to 0.07 M. It is due to the grain size of FTO decrease when the Li+ doping increase in the film. As to the effect of carrier gas, the resistivity of FTO film using N?2 and O2 as carrier gas has 3 orders of magnitude and 2 orders of magnitude higher, respectively, than that using air as carrier gas. The carrier concentration and the mobility of the FTO film using air as carrier gas shows the highest value. Finally, we fabricate dye-sensitized solar cell with FTO substrates having similar sheet resistances but different hazes. It is found that the performance of DSSC with FTO film having higher haze shows better photocurrent and solar cell conversion efficiency.
