Lead-free double perovskite Rb+, Sb3+-codoped Cs2NaInCl6 nanocrystals with highly efficient and tunable photoluminescence

Lead-free double perovskite nanocrystals (LFDP NCs) are promising materials for illumination and display applications because of their potential to overcome the toxicity and instability of lead-based counterparts. Despite the success in the synthesis of LFDP NCs, tunable control over the photoluminescence (PL) of LFDP NCs is still challenging. Herein, brightly emissive and stable Rb+, Sb3+-codoped Cs2NaInCl6 NCs are synthesized while fulfilling tunable self-trapped exciton (STE) emission in the blue region through the A, B-site codoping strategy. Sb3+ is introduced into the B-site of Cs2NaInCl6 NCs to break the parity-forbidden transition and boost the emission efficiency. By further altering the amount of A-site doped Rb+, the emission peak of the NCs is tunable from 447 to 528 nm, because Rb+ enlarges the electron-phonon coupling energy, which leads to larger Stokes shifts and therefore the continuous red-shift of PL emission. The Rb+, Sb3+-codoped Cs2NaInCl6 NCs exhibit robust PL and phase stability against moisture after one year of storage. A series of LFDP NCs with tunable emission are synthesized according to the codoping strategy and further employed as the color conversion materials for fabricating light-emitting diodes.