Yang Yang, Pham Ngoc Duy, Yao Disheng, Fan Lijuan, Hoang Minh Tam, Tiong Vincent Tiing, Wang Zhaoxiang, Zhu Huaiyong, Wang Hongxia
School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty , Queensland University of Technology , Brisbane 4001 , Australia.
Key Laboratory for Renewable Energy, Institute of Physics , Chinese Academy of Sciences , P.O. Box 603, Beijing 100190 , China.
ACS Appl Mater Interfaces. 2019 Aug 7;11(31):28431-28441. doi: 10.1021/acsami.9b07318. Epub 2019 Jul 30.
A carbon electrode with low cost and high stability exhibited competitiveness for its practical application in organic-inorganic hybrid perovskite solar cells (PSCs). Nonetheless, issues such as poor interface contact with an adjacent perovskite layer and obvious hysteresis phenomenon are bottlenecks that need to be overcome to make carbon-based PSCs (C-PSCs) more attractive in practice. Herein, we report an effective method to enhance the interfacial charge transport of C-PSCs by introducing the CuSCN material into the device. Two types of CuSCN-assisted devices were studied in this work. One was based on the deposition of an ultrathin CuSCN layer between the perovskite absorber layer and the carbon cathode (PSK/CuSCN/C), and the other was by infiltrating CuSCN solution into the carbon film (PSK/C-CuSCN) by taking advantage of the macroporous structure of the carbon. We have found that the CuSCN incorporation by both methods can effectively address the hysteretic feature in planar C-PSCs. The origin for the hysteresis evolution was unraveled by the investigation of the energy alignment and the kinetics of interfacial charge transfer and hole trap-state density. The results have shown that both types of CuSCN-containing devices showed improved interfacial charge carrier extraction, suppressed carrier recombination, reduced trap-state density, and enhanced charge transport, leading to negligible hysteresis. Furthermore, the CuSCN-incorporated C-PSCs demonstrated enhanced device stability. The power conversion efficiency remained 98 and 91% of the initial performance (13.6 and 13.4%) for PSK/CuSCN/C and PSK/C-CuSCN, respectively, after being stored under a high humidity (75-85%) environment for 10 days. The devices also demonstrated extraordinary long-term stability with a negligible performance drop after being stored in air (relative humidity: 33-35%) for 90 days.
一种低成本且高稳定性的碳电极在有机-无机杂化钙钛矿太阳能电池（PSC）的实际应用中展现出竞争力。然而，诸如与相邻钙钛矿层界面接触不良以及明显的滞后现象等问题，是制约碳基PSC（C-PSC）在实际应用中更具吸引力的瓶颈。在此，我们报道一种通过将CuSCN材料引入器件来增强C-PSC界面电荷传输的有效方法。本工作研究了两种类型的CuSCN辅助器件。一种是在钙钛矿吸收层和碳阴极之间沉积超薄CuSCN层（PSK/CuSCN/C），另一种是利用碳的大孔结构将CuSCN溶液渗透到碳膜中（PSK/C-CuSCN）。我们发现，通过这两种方法引入CuSCN都能有效解决平面C-PSC中的滞后特性。通过对能量排列、界面电荷转移动力学和空穴陷阱态密度的研究，揭示了滞后演变的根源。结果表明，两种含CuSCN的器件均表现出改善的界面电荷载流子提取、抑制的载流子复合、降低的陷阱态密度以及增强的电荷传输，从而使滞后现象可忽略不计。此外，引入CuSCN的C-PSC表现出增强的器件稳定性。在高湿度（75 - 85%）环境下储存10天后，PSK/CuSCN/C和PSK/C-CuSCN的功率转换效率分别保持初始性能（13.6%和13.4%）的98%和91%。这些器件在空气中（相对湿度：33 - 35%）储存90天后也表现出非凡的长期稳定性，性能下降可忽略不计。
