EPMD: Overcoming Multiscale Heterogeneity of Printed Halide Perovskites with Self-Leveling Inks and Targeted Passivation

Overcoming Multiscale Heterogeneity of Printed Halide Perovskites with Self-Leveling Inks and Targeted Passivation Abstract This project aims to advance emerging electronic and photonic devices based on metal halide perovskites by establishing how the physics of ink formulation and film formation governs device behavior, spatial uniformity, and operational stability. Metal halide perovskites are solution-processable semiconductor materials whose electrical and optical properties can be adjusted to detect or emit different wavelengths of light, making them promising for photodetectors, imaging systems, radiation sensors, solar cells, displays, and flexible electronics. However, current microfabrication approaches do not provide a feasible means of producing microscale patterns containing multiple perovskite compositions while preserving their distinct properties. The mutual solubility of these materials and their sensitivity to processing conditions can produce variations in composition, structure, and defects that limit device performance and reliability. This project will examine how the physical properties of perovskite inks, including their viscosity, wetting, and drying behavior, control film formation, crystallization, and heterogeneity across patterned features. It will connect these phenomena to the electrical and optical properties of the resulting devices, identifying how microscale variations in film thickness, composition, morphology, and defects influence photodetection, imaging, performance uniformity, and degradation. This knowledge will be used to develop materials-design and patterning strategies that improve the control of perovskite films and reduce sources of device variability and instability. The project will also develop spatially targeted ultrathin protective layers to reduce defects in selected regions of perovskite films and enable photodetectors with tunable spectral response. The resulting scientific principles could support improved imaging across a wider range of wavelengths, flexible and energy-efficient displays, advanced radiation detectors, and other perovskite-based electronic and photonic technologies. The project will provide undergraduate and graduate students with hands-on training in semiconductor materials, patterning, and device fabrication, helping prepare a skilled domestic semiconductor workforce and supporting the integration of research into undergraduate education and mentoring. The overarching objective of this project is to overcome multiscale heterogeneity and achieve micron-scale patterning of metal halide perovskites by advancing the understanding of film-formation physics, utilizing Marangoni-driven self-leveling inks, and applying targeted two-dimensional perovskite passivation to create tunable photodetectors. The intellectual merit will be in the modeling and experimental investigation of the fundamental mechanisms governing the size scaling and spatial heterogeneity of perovskite device optoelectronic properties, together with the dynamics of printed-film leveling, drying, and crystallization. The project will test the hypothesis that microscale perovskite uniformity is directly connected to device-level performance, stability, and degradation. Research will quantify the viscosity, surface tension, and dynamic wetting behavior of perovskite inks on planar and mesoporous substrates to understand ink transfer and the development of edge effects from the micrometer to millimeter length scales. The project will identify mechanisms controlling spatial heterogeneity, photoluminescence, and morphology in single- and mixed-halide perovskites and will develop strategies to quantify and mitigate Saffman–Taylor and spinodal fluid instabilities through ink design. Marangoni-driven self-leveling will be investigated as an approach for controlling film uniformity and reducing the spatial variations that influence device physics. The work will directly link local film properties to device-level electrical and optical behavior and to coupled changes in performance and stability during operation. Finally, fluid-mechanics insights will be used to develop spatially targeted two-dimensional perovskite defect passivation that addresses microscale heterogeneity and enables printed two-dimensional/three-dimensional perovskite photodetectors with tunable spectral response. The resulting design principles will be extensible to other deposition methods and will support the development of perovskite-based radiation detectors, multispectral imagers, thin-film transistors, and multicolor light-emitting diode displays. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.