Filterless Flexible Photodetector for Red Light Detection Using Silver Nanowire‐Percolated Zinc Oxide

ABSTRACT Flexible red light‐sensing filterless photodetectors (PDs) have potential applications in next‐generation optoelectronic devices due to better color discrimination, without complex architectural design. This work demonstrates a robust, flexible red sensing hybrid PD fabricated using squaraine (SQ2) dye sensitized zinc oxide (ZnO) and silver nanowires (Ag NWs) absorbing layer stacked on top of Ag NWs/ poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) flexible and transparent conducting interdigitated electrodes. Direct ink writing is used to develop each layer of the PD, with an annealing temperature of 120°C for the semiconducting layer. The developed PD exhibits negative photoconductance due to the Schottky junction formation between ZnO and Ag NWs. The device shows high responsivity (8.85 A/W) and detectivity (2.9 × 10 10 Jones) operating at a very low bias voltage of 0.1 V. The PD also demonstrates excellent mechanical stability, in both bent and straight conditions, while maintaining photo response for nearly 10 000 cycles. Device stability and longevity is also enhanced using transparent and flexible polydimethylsiloxane as an encapsulant. Potential green and blue sensing are also demonstrated by replacing SQ2 with suitable organic dyes, with the same underlying device architecture, thus paving the way to develop dye‐sensitized color filter‐based visible light flexible PD arrays.