Wei Junfeng, Shao Zhipeng, Pan Bin, Chen Shuanghong, Hu Linhua, Dai Songyuan
Key Laboratory of Photovoltaic and Energy Conservation Materials, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China.
Beijing Key Laboratory of Novel Thin-Film Solar Cells, Beijing Key Laboratory of Energy Safety and Clean Utilization, North China Electric Power University, Beijing 102206, China.
Materials (Basel). 2020 Jun 30;13(13):2936. doi: 10.3390/ma13132936.
The tandem pn-type dye-sensitized solar cells (pn-DSCs) have received much attention in the field of photovoltaic technologies because of their great potential to overcome the Shockley-Queisser efficiency limitation that applies to single junction photovoltaic devices. However, factors governing the short-circuit current densities () of pn-DSC remain unclear. It is typically believed that of the pn-DSC is limited to the highest one that the two independent photoelectrodes can achieve. In this paper, however, we found that the available of pn-DSC is always determined by the larger that the photoanode can achieve but not by the smaller one in the photocathode. Such experimental findings were verified by a simplified series circuit model, which shows that a breakdown will occur on the photocathode when the photocurrent goes considerably beyond its threshold voltage, thus leading to an abrupt increase in of the circuit. The simulation results also suggest that a higher photoconversion efficiency of the pn-DSCs can be only achieved when an almost equivalent photocurrent is achieved for the two photoelectrodes.
串联式pn型染料敏化太阳能电池（pn-DSCs）在光伏技术领域备受关注，因为它们极有可能克服适用于单结光伏器件的肖克利-奎塞尔效率限制。然而，影响pn-DSC短路电流密度（）的因素仍不明确。通常认为，pn-DSC的 受限于两个独立光电极所能达到的最高值。然而在本文中，我们发现pn-DSC的可用 总是由光阳极所能达到的较大 值决定，而不是由光阴极中的较小值决定。这样的实验结果通过一个简化的串联电路模型得到了验证，该模型表明，当光电流大幅超过其阈值电压时，光阴极会发生击穿，从而导致电路的 突然增加。模拟结果还表明，只有当两个光电极实现几乎相等的光电流时，pn-DSCs才能实现更高的光电转换效率。
