Department of Bionanotechnology and ‡Department of Chemistry and Applied Chemistry, Hanyang University , 55 Hanyangdaehak-ro, Sangnok-gu, Ansan, Kyeonggi-do 426-791, Republic of Korea.
ACS Appl Mater Interfaces. 2014 Feb 26;6(4):2335-43. doi: 10.1021/am404355m. Epub 2014 Feb 11.
The development of a Pt-free, highly active electrocatalyst for a counter electrode (CE) is vital to the construction of highly efficient quantum dot-sensitized solar cells (QDSSCs). As an alternative to Pt, the use of various metal sulfides, such as Cu2S, CoS, and PbS, has been successfully demonstrated; however, the studies on the utilization of non-sulfide materials have been scarcely reported. In this regard, we examined eight different types of binary metal selenides as new candidate materials, and found that the electrocatalytic activity of Cu1.8Se and PbSe toward polysulfide reduction was superior to that of Pt. In depth investigation into these two materials further revealed that, while the electrocatalytic activity of both metal selenides surpasses that of Pt, the long-term utilization of the PbSe CE is hindered by the formation of PbO on the surface of PbSe, which is attributed to the instability of PbSe under air. Unlike PbSe, Cu1.8Se was found to be chemically stable with a polysulfide electrolyte and was even better than Cu2S, a commonly used CE material for QDSSCs. Using the Cu1.8Se CE, we obtained a power conversion efficiency of 5.0% for CdS/CdSe-sensitized solar cells, which was an efficiency almost twice that obtained from Pt CE. This work provides a new application for metal selenides, which have been traditionally utilized as sensitizers for QDSSCs.
对于构建高效量子点敏化太阳能电池（QDSSCs）而言，开发一种无铂、高效的对电极（CE）电催化剂至关重要。作为 Pt 的替代品，已成功证明了各种金属硫化物（如 Cu2S、CoS 和 PbS）的使用；然而，关于利用非硫化物材料的研究却鲜有报道。在这方面，我们研究了八种不同类型的二元金属硒化物作为新型候选材料，并发现 Cu1.8Se 和 PbSe 对多硫化物还原的电催化活性优于 Pt。对这两种材料的深入研究进一步表明，虽然这两种金属硒化物的电催化活性均优于 Pt，但 PbSe CE 的长期使用受到 PbSe 表面形成 PbO 的阻碍，这归因于 PbSe 在空气中的不稳定性。与 PbSe 不同，Cu1.8Se 被发现与多硫化物电解质具有化学稳定性，甚至优于 CdS/CdSe 敏化太阳能电池中常用的 CE 材料 Cu2S。使用 Cu1.8Se CE，我们获得了 CdS/CdSe 敏化太阳能电池的 5.0%功率转换效率，这一效率几乎是 Pt CE 的两倍。这项工作为金属硒化物提供了一种新的应用，金属硒化物传统上被用作 QDSSCs 的敏化剂。
