Advanced indicone Nanostructuring: Surface engineering with small molecule inhibitors through molecular layer deposition

Our study introduces a novel approach to forming transparent nanostructured surfaces using novel surface engineering technique of indicone, a promising organic–inorganic hybrid material with high potential for next-generation optical applications. By combining an indium metal–organic precursor with phloroglucinol in the MLD process, we achieved indicone layers that exhibit approximately 70% transmittance in the visible spectrum and a refractive index of 1.7–2.0, making them ideal for advanced metasurface application. To gain effective control over surface nucleation and enhance nanostructural definition, we employed N,N-Dimethyltrimethylsilylamine (DMA-TMS) as a small molecule inhibitor (SMI). The inhibitor’s chemical adaptability, reduced steric hindrance, and high surface coverage enabled the controlled growth of indicone nanostructures after 16 MLD cycles, achieving a transparent surface with finely tuned morphology. Also, Atomic Force Microscopy (AFM) provided direct visualization of the nanoscale changes in z-height and morphology, highlighting the successful control achieved through DMA-TMS regulation. Surfaces without SMI treatment showed rapid nucleation and smoothness, emphasizing the impact of our approach in forming nanoscale features. These findings underscore the effectiveness of our surface engineering technique for creating transparent, nanostructured indicone surfaces, with AFM analysis playing a pivotal role in verifying morphological control. This method advances nanofabrication techniques, supporting the integration of indicone in a variety of next-generation optical applications.