Enhancing the performance of perovskite light-emitting diodes via the insertion of NaCl

Abstract

All-inorganic perovskite light-emitting diodes (PeLEDs) have the advantage of narrow band emission, superior thermal stability and high chemical stability. However, CsPbBr3 PeLEDs usually suffered from huge current leakage and low device efficiency due to the poor surface coverage of CsPbBr3 on the hole transport layer (HTL). Thus, improving the morphology of CsPbBr3 layer is an effective strategy to enhance the performance of PeLEDs. In this report, NaCl was introduced on the surface of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) to assist the crystal growth of CsPbBr3. Experimental results show that CsPbBr3 film with less pinholes and lower trap density was obtained, resulting in an enhancement of photoluminescent (PL) intensity. The luminous current efficiency (LE) of PeLED increased from 7.4 cd/A to 12.8 cd/A. The work mechanism of the introduction of NaCl was discussed. This work provides an effective and convenient method to improve the efficiency of all-inorganic PeLEDs.