Reducing Nonradiative Recombination Losses in Tin-Based Perovskite LEDs Utilizing a Self-Assembled Monolayer

Tin-based perovskites are emerging as less-toxic alternatives to their lead-based counterparts for optoelectronic devices, such as solar cells and light-emitting diodes (LEDs). However, despite their great potential, the efficiency of pure red tin-based perovskite LEDs (Sn-LEDs) still lags behind that of lead-based perovskite LEDs (Pb-LEDs), partly due to the poor electron blocking at the PEDOT:PSS/perovskite interface. This leads to detrimental nonradiative recombination pathways that limit the performance of the LEDs. In this study, we replaced the conventional PEDOT:PSS layer with the self-assembled monolayer (SAM) EADR03, presenting, to the best of our knowledge, the first report of a SAM employed as a hole-selective layer in Sn-LEDs. EADR03 simultaneously acted as an efficient electron-blocking and hole-injecting layer, thereby reducing interfacial recombination losses and enhancing the LEDs' performance. As a result, we achieved a 3-fold enhancement in external quantum efficiency, propelling the advancement of more efficient tin-based perovskite LEDs.