Aromatic Carboxylic Acid Ligand Management for CsPbBr3 Quantum Dot Light-Emitting Solar Cells

The commonly used long-chain ligands in CsPbBr3 quantum dots (QDs) hinder the electronic coupling and charge transport in optoelectronic devices; therefore, surface ligand management is crucial to optimize device performance. In this report, we demonstrate a simple and feasible aromatic carboxylic acid ligand management to obtain high-efficiency CsPbBr3 QD light-emitting solar cells (LESCs). Benzoic acid (BA) is used to replace the excess insulating ligands so that the charge transport of QD films is greatly improved, and the trap-assisted nonradiative recombination is also effectively inhibited. Consequently, the CsPbBr3 QD LESCs yield an enhanced power conversion efficiency (PCE) of 5.46% for the champion device and function as green light-emitting diodes (LEDs) with a maximum brightness of 584 cd/m2. This work sheds light on the ligand management in perovskite QDs and provides a new avenue to realize high-performance multifunctional optoelectronic devices based on perovskite QDs.