Factors controlling charge recombination under dark and light conditions in dye sensitised solar cells.
Factors controlling charge recombination under dark and light conditions in dye sensitised solar cells.
复制标题
DOI：
10.1039/c0cp01855d
复制
发表时间：
2011-02
期刊：
影响因子：
--
通讯作者：
Piers R. F. Barnes;Assaf Y Anderson;Mindaugas Juozapavicius;Lingxuan Liu;Xiaoe Li;E. Palomares;Amparo Fo
中科院分区：
文献类型：
--
作者：
Piers R. F. Barnes;Assaf Y Anderson;Mindaugas Juozapavicius;Lingxuan Liu;Xiaoe Li;E. Palomares;Amparo Fo
本文提出了一种简单而有效的方法来评估染料敏化太阳能电池（DSSC）中复合损失随TiO（2）电子浓度（n）变化的电流电压曲线（j-V）。与电解质中的碘物质和氧化的染料分子复合的电子的总通量可以被认为是复合电流密度，定义为j（rec）= j（inj）-j，其中j（inj）是从光激发染料态注入的电子的电流，j是在电池电压（V）下收集的电流密度。在任何给定的操作条件下的电子浓度由电荷提取确定。这允许在匹配的n下比较影响电子复合率的因素。我们表明，j（rec）通常是2-3倍高1太阳等效照明（j（inj）> 0）相对于黑暗（j（inj）= 0）的条件。增加光照强度、电解质碘浓度和电解质溶剂粘度会增加这种差异。增加电解质碘化物浓度和提高温度可以减小这种差异。这些结果使我们能够验证完整操作单元的数值模型（巴恩斯等人，物理化学化学物理，DOI：10.1039/c 0 cp 01554 g），并将j（rec）的差异与器械中的物理过程联系起来。亮和暗中的j（rec）之间的差异可以通过两个因素来解释：（1）相对于电流在相反方向上流动的暗条件，当电流在照明下流动时电子受体物质（I（3）㈠和/或I（2））的浓度增加，以及（2）在光条件下电子复合对氧化染料分子的重要贡献。更一般地，该技术有助于将观察到的DSSC的组分、处理和性能之间的关系分配给更基本的物理过程。
A simple and powerful approach for assessing the recombination losses in dye sensitised solar cells (DSSCs) across the current voltage curve (j-V) as a function of TiO(2) electron concentration (n) is demonstrated. The total flux of electrons recombining with iodine species in the electrolyte and oxidised dye molecules can be thought of as a recombination current density, defined as j(rec) = j(inj)-j where j(inj) is the current of electrons injected from optically excited dye states and j is the current density collected at cell voltage (V). The electron concentration at any given operating conditions is determined by charge extraction. This allows comparison of factors influencing electron recombination rates at matched n. We show that j(rec) is typically 2-3 times higher under 1 sun equivalent illumination (j(inj) > 0) relative to dark (j(inj) = 0) conditions. This difference was increased by increasing light intensity, electrolyte iodine concentration and electrolyte solvent viscosity. The difference was reduced by increasing the electrolyte iodide concentration and increasing the temperature. These results allowed us to verify a numerical model of complete operational cells (Barnes et al., Phys. Chem. Chem. Phys., DOI: 10.1039/c0cp01554g) and to relate the differences in j(rec) to physical processes in the devices. The difference between j(rec) in the light and dark can be explained by two factors: (1) an increase in the concentration of electron acceptor species (I(3)(-) and/or I(2)) when current is flowing under illumination relative to dark conditions where the current is flowing in the opposite direction, and (2) a non-trivial contribution from electron recombination to oxidised dye molecules under light conditions. More generally, the technique helps to assign the observed relationship between the components, processing and performance of DSSCs to more fundamental physical processes.