0, 1, 2, and 3-Dimensional zinc oxides enabling high-efficiency OLEDs

In the pursuit of high-efficiency organic light-emitting diodes (OLEDs), this paper unveils the potential of zinc oxide (ZnO) nanostructures of various dimensions (0,1,2, and 3D), doped in hole injection layer (PEDOT:PSS). Unique enhancements were demonstrated in forms from nanoparticles (0D) to nanowires (1D), nanosheets (2D), and nanoflowers (3D), revolutionizing OLED performance. Specifically, the incorporation of 0D-ZnO doped in PEDOT:PSS resulted in remarkable efficiency improvements of 19 % in maximum power efficacy (PEmax), 19 % in maximum current efficacy (CEmax) and 24 % in maximum external quantum efficiency (EQEmax), compared with the undoped counterpart. Elevating the dimensions to 1D-ZnO (20 nm), when doped in PEDOT:PSS, enabled an increment of 46, 54 and 64 % in PEmax, CEmax and EQEmax, respectively. Furthermore, 2D-ZnO (annealed at 400 °C) doped in PEDOT:PSS achieved notable performance improvements, with enhancements of 24 % in PEmax, 23 % in CEmax, and 28 % in EQEmax. Despite size limitations, 3D-ZnO doped in PEDOT:PSS exhibited enhancements of 11 % in PEmax, 15 % in CEmax, and 20 % in EQEmax. We achieved the best results by integrating 1D-ZnO into PEDOT:PSS, which may be attributed to the small diameter of the 1D-ZnO structure when compared to 0D, 2D, and 3D ZnO, resulting in superior OLED performance. These findings demonstrate the significant potential of ZnO nanostructures doped in PEDOT:PSS in enhancing the performance of green OLEDs, and paving the way for more sustainable, cost-effective, and efficient OLEDs for display and lighting applications. Continued research on ZnO and other inorganic materials holds promise for further advancements in OLED technology and a brighter, more energy-efficient future.