In Situ Ligand Bonding Management of CsPbI₃ Perovskite Quantum Dots Enables High‐Performance Photovoltaics and Red Light‐Emitting Diodes

Abstract

To fine-tune surface ligands towards high-performance devices,wedeveloped an in situ passivation process for all-inorganic cesium lead iodide (CsPbI 3)perovskite quantum dots (QDs) by using ab ifunctional ligand, L-phenylalanine (L-PHE). Through the addition of this ligand into the precursor solution during synthesis,t he in situ treated CsPbI 3 QDs displays ignificantly reduced surface states,i ncreased vacancy formation energy,higher photoluminescence quantum yields,and muchimproved stability.Consequently,the L-PHE passivated CsPbI 3 QDs enabled the realization of QD solar cells with an optimal efficiency of 14.62 %a nd red lightemitting diodes (LEDs) with ah ighest external quantum efficiency (EQE) of 10.21 %, respectively,d emonstrating the great potential of ligand bonding management in improving the optoelectronic properties of solution-processed perovskite QDs.

Flexible and efficient perovskite quantum dot solar cells via hybrid interfacial architecture

“…Colloidal quantum dots (QDs) have remarkably tunable properties such as size-dependent absorption and emission wavelengths and energy levels, exhibit efficient multiple exciton effects, and compared to other solution-processed materials show decent stability 1 – 8 . These unique features facilitate their wide applications in optoelectronic devices such as photodetectors 9 – 12 , light-emitting diodes 13 , 14 , and photovoltaics 15 – 17 . The best PbS QD solar cell has achieved a power conversion efficiency (PCE) of 13.8% due to improvements in surface passivation and device structure 18 .…”

The role of sodium in stabilizing tin–lead (Sn–Pb) alloyed perovskite quantum dots

“…95,96 The usage of slab models to investigate the properties of perovskite QDs has also led to many successes in previous works. 63,66,97,98 To understand the surface ligand effect to the QDs, the slab model used above were passivated by oleylammonium (C 18 H 35 NH 3 + : OLA) or oleate (C 18 H 34 O 2 -: OA) on CsI or MI 2 termination, respectively. To validate our ligand slab model, we also calculated the ligand density and compared it with experiment data (Table S1).…”

“…For Sn-contained QDs, the stronger interaction between ligands and the surface has been proven with a stabilization effect. [63][64][65][66] Overall, the prerequisite of retrieving near-infrared emission for these Sn-contained QDs is to enhance the bonding strength between the Sn 2+ and Iions and passivation effect of surface ligands.…”

Anchorable Perylene Diimides as Chemically Inert Electron Transport Layer for Efficient and Stable Perovskite Solar Cells with High Reproducibility

“…In this context, organic n‐type semiconductors are superior as they possess definite molecular structures, which ensure controllable surface compositions and even molecular packing in the ETL. [ 15–17 ] Furthermore, the optoelectronic properties of organic semiconductors are broadly tunable via molecular engineering, and organic ETLs can be fabricated at milder conditions than those of inorganic oxide semiconductors. [ 18–21 ] However, the relatively low electron mobility and weak adhesion of molecular semiconductors to the transparent conducting substrate largely restrict their application in n–i–p‐structured PSCs.…”