500 likes | 1.1k Views
Semiconductor (Quantum dots) sensitized solar cells . DSSC 的缺點. 染料 : dye 只能吸收一部分的太陽光譜 (dye:350-750 nm, 太陽光 350-2500 nm). 電解液 : 碘離子具腐蝕性 電解液 液體 怕漏 光電子會 recombination ,降低電池之電流及效率。. 染料為有機物 (organic) ,遇高溫會破壞 有機物長時間穩定性較差,壽命問題. Semiconductor 為無機物,熔點高,長期穩定 無機物比較不怕電解液腐蝕
E N D
DSSC 的缺點 • 染料: dye 只能吸收一部分的太陽光譜 (dye:350-750 nm, 太陽光350-2500 nm). • 電解液: 碘離子具腐蝕性 • 電解液液體怕漏 • 光電子會recombination,降低電池之電流及效率。
染料為有機物(organic) ,遇高溫會破壞 有機物長時間穩定性較差,壽命問題
Semiconductor 為無機物,熔點高,長期穩定 無機物比較不怕電解液腐蝕 可用的semiconductor 選擇多,發展空間大 Semiconductor sensitizers
Extremely thin absorber semiconductor sensitized solar cells (極薄層半導體敏化太陽電池-solid state)
Semiconductor absorber materials: PbS, CdSe, CdS, In2S3, Sb2S3, Cu2-xS • Ternary semiconductors: CuInSe, AgSbS, AgBiS,…. • electron conductor:TiO2 • hole conductor: CuSCN, PEDOT, spiro-ometad • Thickness of semiconductor absorber: ~ several nm or 10 nm. • A solid-state solar cell. • Efficiency 11%
Quantum-dot sensitized solar cells • What is a quantum dot: a nanoparticle of diameter several nm to a few hundred nm. • When diameter ~ 10-20 nm, quantum effect occurs. • Quantum dot semiconductor materials: CdS, CdSe, CdTe, PbS, PbSe, InP, InAs, Ag2S, Ag2Se, CuXS etc.
Advantages of QD-DSCs • 吸收能帶可調整 (tunable absorption bands)—quantum size effect • 高吸收係數 (high extinction coefficients)—吸光能力較染料高 • 多電子電洞對生成(multiple electron-hole pair generation)-一個入射光子可產生數e-h對,量子效率大於100% 。 • 可以液態或固態
Quantum size effect –QD radius decrease, energy gap increase
semiconductor quantum dots製造方法 CBD: chemical bath deposition SILAR (successive ionic layer adsorption and reaction) Hydrothermal (水熱法)
Chemical bath depostion將 Cd+2與S-2離子容易混在一起,形成ion-by-ion 生長
SILAR growth 原理 (陽離子與陰離子分批長在基板)
例子: CdS quantum dots合成 ethanol ethanol
Dependence of I-V curves on radiation power for Ag2S solar cells
Table 1.Photoelectrochemical performance of Ag2Se-QD sensitized solar cells with different SILAR cycles
SILAR SILAR 自動化生產設備