Room Temperature Processed Amorphous Sn‐Excess‐ITO Electrodes for High Performance Perovskite Light‐Emitting Diodes

Achieving high efficiency perovskite light‐emitting diodes (PeLEDs) requires transparent electrodes that combine low sheet resistance, high optical transmittance, and atomically smooth morphology. Conventional crystalline indium tin oxide (ITO) electrodes, however, necessitate high‐temperature deposition above 300°C or post‐annealing, resulting in grain boundaries and rough surfaces that are incompatible with flexible substrates and low‐temperature device architecture. Here, we report room‐temperature processed, grain boundary‐free Sn excess doped indium tin oxide (SE‐ITO) electrodes fabricated via RF‐RF co‐sputtering of In 2 O 3 and SnO 2 . Through the heavy incorporation Sn 4+ dopants (19 wt.%) and optimized oxygen‐vacancy engineering, the amorphous SE‐ITO achieves an exceptional combination of low sheet resistance (10 Ω sq −1 ) and high visible transmittance (85%), comparable to thermally annealed crystalline ITO. When implemented as the transparent anodes in green PeLEDs, the amorphous SE‐ITO films enable a peak external quantum efficiency of 17.5% and a maximum luminance of 1860 cd m −2 , outperforming devices using commercial crystalline ITO (16.3%, 1690 cd m −2 ). These results establish fully amorphous, room‐temperature SE‐ITO electrodes as a viable alternative to crystalline counterparts, offering a new pathway toward flexible, high‐efficiency, and thermally compatible PeLED technologies.