Kinetically Controlled Direct In Situ Photolithography of Perovskite Color-Conversion Layers

Metal halide perovskites (MHPs) are promising materials for color-conversion layers (CCLs) owing to their high absorption coefficients and narrow emission bandwidths. However, high-resolution patterning of micrometer-thick MHP CCLs remains challenging due to their susceptibility to optical and chemical damage during conventional patterning processes. Direct in situ photolithography has emerged as a potential solution by enabling high-thickness pattern formation without directly exposing MHP emitters to harsh conditions, yet its achievable spatial resolution has remained limited. Here, we report a kinetically controlled direct in situ photolithography (KC-ISP) approach for high-resolution MHP CCLs. By controlling thiol-ene crosslinking kinetics and incorporating a precursor-redistributing spin-washing step, KC-ISP enables high-resolution patterning with feature sizes down to ∼3 µm while providing facile color tunability through controlled precursor composition. In addition, in situ crystallized MHPs exhibit a pronounced increase in photoluminescence quantum yield upon air exposure, attributed to phase redistribution and surface defect passivation under ambient conditions. As a result, our MHP CCLs with ∼4 µm thickness achieve blue uptake values of ∼80% and ∼98% for green and red emitters, respectively, with corresponding color-conversion efficiencies of ∼45% and ∼30%, demonstrating the potential of KC-ISP for high-resolution micro-display applications.