Visible/fluorescent dual-mode dichroic dye-doped PDLC pixels enabled by photolithographic fabrication for multicolor patterned display and information encryption

Dichroic dye doping and electrical driving enable Vis/UV color modulation. • Single-layer 75 μm color PDLC pixel arrays are realized by photolithography. • Multicolor patterned display is achieved by voltage-controlled pixel switching. • Region-addressed pixels enable multilevel optical information encryption. Polymer dispersed liquid crystals (PDLCs) show reversible voltage-controlled switching between light-scattering and transparent states, but their intrinsic colorless nature limits their applications in multicolor display and multilevel information encryption. To overcome these limitations, this work demonstrates a single-layer pixelated dual-mode PDLC device by combining photolithographically defined microchannels with dichroic dye-doped PDLCs (DPDLCs). In this design, the CMY system is used for visible-light subtractive color modulation, while the UV-excited fluorescence provides an additional hidden readout channel for information encryption. The anisotropic absorption and fluorescence emission of dichroic dyes, together with the electrically tunable response of PDLCs, enable voltage-controlled visible color modulation and UV-excited fluorescence modulation. Through photolithographic fabrication and selective filling, cyan, magenta, and yellow DPDLC units were spatially integrated into single-layer CMY pixel panels. The fabricated devices exhibited well defined subpixel arrays with an individual stripe width of approximately 75 μm, moving PDLC color devices from macroscopic patterned films toward microscale pixelated structures. The distinct voltage responses of different DPDLC formulations further enable stepwise electrical color modulation of the CMY pixel devices, resulting in electrically tunable multicolor states with stable cycling performance. By combining the pixelated DPDLC devices with patterned electrodes, voltage-controlled multicolor patterned display and dual-mode information encryption are further demonstrated. This strategy provides a feasible route for constructing microscale pixelated DPDLC color devices with electrically tunable visible/fluorescent responses for patterned display and information encryption applications. Download: Download high-res image (142KB) Download: Download full-size image