Boosting Electronic Properties of CsPbBr<sub>3</sub> Nanocrystals via Lithium‐Ion Doping and Surface Passivation for Enhanced Electrical Conductivity and Efficient White Light‐Emitting Diodes
Zhongsheng Ge, Siyuan Wan, Muhammad Moin, Sk Abdul Moyez, Lizhuang Dong, Hamood ur Rehman Haris, Marek Piotrowski, Zhiming Wang, Tim Leydecker, Udayabhaskararao Thumu
Abstract
Abstract Lithium's interaction with CsPbBr 3 nanocrystals (NCs), can enhancing its intrinsic electrical conductivity (σ) for high‐performance device applications. Herein, two distinctly different modes of Li⁺ interaction with CsPbBr 3 NCs: minor lattice insertion (0.07% relative to Cs) and predominant surface passivation is reported through Li m Pb n alloy formation. In contrast, Li⁺ exhibits significantly reduced interaction with Cs 4 PbBr 6 NCs, which could be due to the persence of lower amount of Pb 2+ on the surface of these structures. The σ of CsPbBr 3 : x Li + NCs through bottom‐contact devices exhibited a gradual increase from 2.1 × 10 −7 to as high as 2.5 × 10 −6 S m −1 , which is a 50‐fold improvement compared to CsPbBr 3 NCs. The enhanced σ is attributed to the presence of Li + doping and surface passivation of CsPbBr 3 by the Li m Pb n ligated complexes. DFT calculations revealed electron movement from the valence and to conduction band and a reduced bandgap further supporting the inferences from experimental studies. The unique feature of the increased luminescence and σ of CsPbBr 3 :Li + NCs is explored for fabricating white light emitting diodes. The luminescence efficacy of the device is in the range of 88.5 to 112.5 lm W −1 which is higher compared to pure CsPbBr 3 NCs (96.5 lm W −1 ), offering a pathway for advanced optoelectronic applications.