硫化铅胶体量子点的溶剂工程及光电器件性能研究

Solvent Engineering of Lead Sulfide Colloidal Quantum Dots for Optoelectronics

量子点光电器件以近红外吸收的硫化铅(PbS)胶体量子点(CQDs)为代表,因其带隙可调、吸收系数高、具备多激子效应和可溶液化加工等优点而受到广泛关注。然而,囿于胶体稳定性,PbS CQDs光电器件大规模制备困难、商业化进度迟缓。为解决该问题,本工作首先通过配体交换制备了溶液稳定性良好的量子点,进而开发了新型正丁胺/氯苯混合溶剂。以正丁胺为溶剂的量子点在空气条件下最多保存3 d,而以正丁胺/氯苯为溶剂的量子点可以保存至少15 d。紫外可见吸收光谱和荧光光谱结果显示混合溶剂中的量子点表现出优异的尺寸均一性。最终,通过该溶剂工程制备的PbS CQDs太阳能电池器件光电转换效率达到了5.18%,光电探测器的响应度和探测率分别为0.18 A·W^(-1)和1.05×10^(12)Jones。

PbS colloidal quantum dots(CQDs)exhibit the peculiar optical properties for optoelectronic devices including their near-infrared absorption,high absorption coefficient,tunable optical bandgaps,multiple exciton generation and solution processability.However,the inherent colloidal stabilities of CQDs hinders their practical applications.Herein,PbS CQDs with good solution stability were prepared by ligand exchanging.Furthermore,n-butylamine/chlorobenzene solvent was employed to enhance solution stability of PbS CQDs which can be stored at low temperature for at least 15 days,while those in n-butylamine solvent cannot be saved for more than 3 days.UV-vis and PL characterization was then employed to compare the optical properties of CQDs in different solvent via complementary analysis and it is found that PbS CQDs in the mixed solvent exhibit excellent size uniformity.Finally,the solar cells based on mixed solvent realize a power conversion efficiency of 5.18%,while the photodetectors also exhibit a higher responsivity of 0.18 A·W^(-1)and detectivity of 1.05×10^(12)Jones.