Smock Sara R, Williams Travis J, Brutchey Richard L
Department of Chemistry, University of Southern California, Los Angeles, CA, 90089, USA.
Loker Hydrocarbon Institute, University of Southern California, Los Angeles, CA, 90089, USA.
Angew Chem Int Ed Engl. 2018 Sep 3;57(36):11711-11715. doi: 10.1002/anie.201806916. Epub 2018 Aug 7.
Cesium lead halide perovskites are an emerging class of quantum dots (QDs) that have shown promise in a variety of applications; however, their properties are highly dependent on their surface chemistry. To this point, the thermodynamics of ligand binding remain unstudied. Herein, H NMR methods were used to quantify the thermodynamics of ligand exchange on CsPbBr QDs. Both oleic acid and oleylamine native ligands dynamically interact with the CsPbBr QD surface, having individual surface densities of 1.2-1.7 nm . 10-Undecenoic acid undergoes an exergonic exchange equilibrium with bound oleate (K =1.97) at 25 °C while 10-undecenylphosphonic acid undergoes irreversible ligand exchange. Undec-10-en-1-amine exergonically exchanges with oleylamine (K =2.52) at 25 °C. Exchange occurs with carboxylic acids, phosphonic acids, and amines on CsPbBr QDs without etching of the nanocrystal surface; increases in the steady-state PL intensities correlate with more strongly bound conjugate base ligands.
卤化铯铅钙钛矿是一类新兴的量子点，已在多种应用中展现出前景；然而，它们的性质高度依赖于其表面化学。至此，配体结合的热力学仍未得到研究。在此，利用核磁共振方法对CsPbBr量子点上配体交换的热力学进行了量化。油酸和油胺天然配体均与CsPbBr量子点表面动态相互作用，各自的表面密度为1.2 - 1.7 nm 。10 - 十一碳烯酸在25℃下与结合的油酸根发生放能交换平衡（K = 1.97），而10 - 十一碳烯基膦酸发生不可逆的配体交换。10 - 十一碳烯 - 1 - 胺在25℃下与油胺进行放能交换（K = 2.52）。CsPbBr量子点上的羧酸、膦酸和胺发生交换时，纳米晶体表面未被蚀刻；稳态PL强度的增加与结合更强的共轭碱配体相关。
