High-Throughput Synthesis and Screening of Mn²⁺ Doped Perovskite Nanoparticle Megalibraries for Customized Single-Component White Light Emitters

Materials that efficiently convert energy into white light would mitigate the consumption of energy in optoelectronic applications, such as lighting and displays. Yet commercial white light generation currently relies on devices that incorporate multiple materials, including color conversion layers, which suffer from issues like long-term instability. One solution to this challenge is to explore materials capable of single-component white light emission while simultaneously accommodating different emission channels to achieve polychromatic light. In this pursuit, here we explore metal halide perovskite materials using high throughput synthesis of Mn²⁺ doped PEA₂PbX₄ (PEA: Phenethylammonium, X: halide anions) nanoparticle (NP) megalibraries. Megalibraries are centimeter scale chips that contain millions to billions of individually addressable NPs prepared by scanning probe lithography techniques. In this work, we combine evaporation-crystallization polymer pen lithography, thermal annealing assisted doping and solvent vapor assisted recrystallization processes to yield Mn²⁺ doped NP megalibraries. Single particle optical studies revealed that dual-wavelength photoluminescence (PL) profiles of the obtained Mn²⁺ doped perovskite NPs originated from both exciton recombination and energy transfer processes. Combinatorial synthesis and high throughput PL screening of NP megalibraries were also pursued and analysis of the composition-PL-chromaticity coordinate relationships resulted in a “chromaticity triangle” tuning diagram. The ideal perovskite composition for white light emission was identified within a megalibrary containing a compositional gradient (i.e., PEA₂Pb_1-xMn_xBr_4-4yI_y(0≤x≤1, 0≤y≤1)). This study advances our understanding of composition-structure-function relationships of doped perovskite NPs and exemplifies how NP megalibraries can be used to accelerate materials discovery for next-generation optoelectronic materials for solar energy conversion applications.