Ultralow Turn-On Voltage Organic Upconversion Devices for High-Resolution Imaging Based on Near-Infrared Homotandem Photodetector

In recent years, infrared visualization technology has attracted significant attention, and organic upconversion devices (OUDs) have become a reliable infrared imaging strategy due to the superiority of low cost, simple structure, and large-area imaging. Nonetheless, the power consumption of OUDs is mostly high, so effectively reducing the turn-on voltage (V_on) has emerged as a crucial aspect in optimizing OUD performance, alongside the urgent need to enhance imaging resolution. This work presents an efficient OUD integrating a homotandem photodetector and an organic light-emitting diode to reduce the V_on of the OUD since the homotandem detection unit can generate nearly twice the open-circuit voltage (V_oc) compared to the single detection unit. The device reaches a noteworthy V_on of 0.64 V, which is the lowest V_on reported for OUDs, accompanied by a high upconversion efficiency of 10.64% and a wide luminance linear dynamic range (L-LDR) of 82.94 dB. In addition, high-quality bioimaging with wide operating voltages is demonstrated, achieving imaging resolution up to 5799 pixels per inch (ppi). This work demonstrates an effective technical approach to reduce the power consumption of OUDs and facilitate future bioimaging applications.