Ezekiel, Ubokobong2026-04-272026-04-272026-04-272026-04-21https://hdl.handle.net/10012/23067Micro–light-emitting diodes (microLEDs) have emerged as a leading platform for next-generation emissive displays and solid-state lighting, offering exceptional brightness, energy efficiency, and modulation bandwidth. However, realising high resolution full-colour microLED systems remains constrained by the lack of scalable, high-precision phosphor-deposition technologies capable of producing uniform, tunable, and geometrically precise colour-conversion layers at the micron scale. Conventional phosphor-coating approaches, such as spin-coating, inkjet deposition, and particle–binder lamination, struggle to meet the stringent spatial and colourimetric tolerances demanded by microLED pixels. This work addresses the development of a novel colour conversion approach using engineered phosphor inks, with a focus on their formulation, printability, and optical performance for advanced display applications. An experimental framework is established to investigate the feasibility of depositing these phosphor-based materials via stereolithography (SLA) 3D printing to form uniform thin films. The study evaluates the printability of high-loading phosphor composites, identifying critical process limitations such as scattering-induced lateral curing and ultraviolet (UV) dose interactions, which define a practical feature resolution of 125– 150 µm for 25 vol% formulations. To enable consistent film fabrication, mechanical modifications to the printing platform including tilt compensation and enhanced structural rigidity are implemented, resulting in high-uniformity blanket films with controlled thicknesses of 86.8 ± 8 µm and 132.2 ± 7 µm. In parallel, the optical properties of the engineered phosphor ink and printed films are systematically characterized. Raw phosphor analysis confirms stable silicate amber emission centered at 595 nm, while polymer embedding significantly enhances emission intensity by more than 40× due to improved optical extraction. The printed films are further evaluated through colourimetry, spectral analysis, brightness measurements, and accelerated UV ageing tests. A full-factorial colour-point study comprising 63 remote-phosphor samples and 21 direct-print microLED samples quantifies the influence of thickness, solid loading, phosphor concentration, and yellow dopant level on CIExy chromaticity. Statistical analysis reveals that brightness is dominated by phosphor loading (βph ≈ 7.08, p ≈ 0.014), with yellow doping as a secondary contributor (βy ≈ 2.38). Coefficients of variation (0.40–0.48) highlight moderate spatial non-uniformity driven by residual thickness variation and particle aggregation. Accelerated UV-weathering tests show that small-milled particles exhibit significantly improved chromatic stability (∆E < 2 at 3500 kJ/m2), while unmilled and high-doping samples show marked degradation. A physics-based simulation framework is developed to replicate microLED excitation of printed phosphor layers, accurately predicting chromaticity drift as a function of film thickness and phosphor loading. Optimal colour conversion is identified at approximately 15 vol% phosphor and thicknesses exceeding 200 µm, demonstrating strong agreement between simulation and experimental results. These findings are supported by integrated simulation-driven validation and experimental measurements, enabling systematic analysis of performance trends and verification against industry-defined colour and reliability targets. Collectively, this work demonstrates that SLA 3D printing enables precise, tunable, and mechanically robust phosphor architectures, establishing additive manufacturing as a viable and scalable pathway for next-generation microLED colour conversion technologies.enmicroLED3D printingstereolithography (SLA)phosphor designchromaticity (CIExy)next-generation displaysMaster Thesis