Photovoltage‐Driven Two‐Transistor–One‐Diode Perovskite Pixels for In‐Cell Optical Sensing Displays

Abstract

ABSTRACT In‐cell optical sensing displays are essential for next‐generation interactive electronics, yet conventional architectures rely on separate light‐emitting diodes (LEDs) and photodetectors (PDs), limiting pixel density and efficiency. Achieving both functions within a single diode is intrinsically difficult because electroluminescence requires strong excitonic recombination, whereas photodetection benefits from efficient carrier separation. Here, we realize stable dual‐mode operation by stabilizing intermediate‐n quasi‐2D phases and suppressing non‐radiative losses with a fluorinated acid passivator, and by engineering high‐mobility transport layers with a dissociative (type‐II) perovskite/electron transport layer heterojunction to assist exciton dissociation under photovoltaic operation. The resulting bifunctional diode enables an opto‐dynamic random‐access memory (opto‐DRAM) pixel, a two‐transistor–one‐diode (2T1D) architecture conceptually analogous to a two‐transistor–one‐capacitor (2T1C) DRAM gain‐cell, where photovoltage‐driven rather than photocurrent‐driven detection enables self‐amplified sensing when coupled to thin‐film transistors. The sky‐blue PeLED achieves an external quantum efficiency of 20.4% at 100 cd m −2 and a record power efficiency of 41.8 lm W −1 , while as the coupled sensing pixel it exhibits a maximum responsivity of 4.17 × 10 4 A W −1 and a specific detectivity of 6.46 × 10 13 Jones. Monolithic integration yields an active‐matrix display capable of switchable emission and imaging functions offering a scalable platform for compact, energy‐efficient, and multifunctional optoelectronics.