報告書番号

Q06010

タイトル（和文）

色素増感太陽電池の電流-電圧特性のシミュレーションモデルの開発

タイトル（英文）

Computer Simulation of Current-Voltage Characteristics in Dye-Sensitized Solar Cells

概要 （図表や脚注は「報告書全文」に掲載しております）

色素増感太陽電池の電流-電圧特性のためのシミュレーションモデルを開発した。最近、酸化チタン微結晶の格子欠陥等を介した電子拡散が、電池の主要な動作の律速過程であることが報告されている。これらを考慮して色素酸化体と電子の再結合等を新たに定式化して基礎方程式を拡張し、色素増感太陽電池の主要な電子移動を全て含んだモデルを開発した。さらに、新たに導出したモデルを用いて各種再結合が電流-電圧特性に与える影響を分析した。

概要 （英文）

A theoretical model of the charge transport and recombination in dye-sensitized solar cells was developed for computer simulations of current-voltage curves. In the model, we highlight dispersive electron transport involving trapping/detrapping in the nanocrystalline TiO2 photoelectrde; the rate-limiting process of recombination was assumed to be the dispersive electron transport, rather than electron transfer reactions at the TiO2 surfaces. We classify the electron recombination into three paths: two terms relevant to oxidized electrolytic species, REL and REH,for low and high light intensities, respectively, and one term, RD, of dye cations. The difference between REL and REH is a reaction which provides oxidized electrolytic radicals. We checked a typical I-V curve was consistent with an experimental I-V curve. A remarkable result of the modeling is less significance of the current equation of oxidized electrolytic species. In usual cases, assuming a homogeneous concentration for oxidized electrolytic species, numerical errors of solar cell output is very small, typically smaller than 1%; this suggests computational task may be significantly reduced, neglecting the current equation of the redox species. Changes in I-V curves with increasing REH and RD have similar trends in regions of small and moderate recombination: relatively small recombination decreases only photovoltage, and both photocurrent and photovoltage deteriorate in moderate recombination. In relatively large recombination of RD, an inflection point in I-V curves is observed, leaving only photovolatge relatively high values; this anomalous I-V curve was also reported in literature. Differences of the modeling compared with conventional simulation models are also discussed.

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