Department of Materials Science and Engineering and California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.
National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
Adv Mater. 2019 Sep;31(37):e1900111. doi: 10.1002/adma.201900111. Epub 2019 Jul 25.
Halide perovskite colloidal quantum dots (CQDs) have recently emerged as a promising candidate for CQD photovoltaics due to their superior optoelectronic properties to conventional chalcogenides CQDs. However, the low charge separation efficiency due to quantum confinement still remains a critical obstacle toward higher-performance perovskite CQD photovoltaics. Available strategies employed in the conventional CQD devices to enhance the carrier separation, such as the design of type-Ⅱ core-shell structure and versatile surface modification to tune the electronic properties, are still not applicable to the perovskite CQD system owing to the difficulty in modulating surface ligands and structural integrity. Herein, a facile strategy that takes advantage of conjugated small molecules that provide an additional driving force for effective charge separation in perovskite CQD solar cells is developed. The resulting perovskite CQD solar cell shows a power conversion efficiency approaching 13% with an open-circuit voltage of 1.10 V, short-circuit current density of 15.4 mA cm , and fill factor of 74.8%, demonstrating the strong potential of this strategy toward achieving high-performance perovskite CQD solar cells.
卤化物钙钛矿胶体量子点 (CQD) 由于其光电性能优于传统的硫属化物 CQD，因此最近成为 CQD 光伏领域的热门研究课题。然而，由于量子限制导致的电荷分离效率低仍然是高性能钙钛矿 CQD 光伏的一个关键障碍。在传统 CQD 器件中采用的提高载流子分离的策略，如设计 II 型核壳结构和多功能表面修饰来调节电子性能，由于难以调节表面配体和结构完整性，仍然不适用于钙钛矿 CQD 体系。本文提出了一种简便的策略，利用共轭小分子为钙钛矿 CQD 太阳能电池提供额外的驱动力，从而有效实现电荷分离。所得的钙钛矿 CQD 太阳能电池的功率转换效率接近 13%，开路电压为 1.10V，短路电流密度为 15.4mA/cm2，填充因子为 74.8%，证明了该策略在实现高性能钙钛矿 CQD 太阳能电池方面具有很大的潜力。
