Metal Halide Perovskite‐Gated Organic Phototransistors for Efficient UV/DUV Detection

Abstract Conventional UV/DUV phototransistors, which rely on wide‐bandgap semiconductor channels, encounter issues with material availability, processing complexity, and performance tunability. Perovskite‐gated phototransistors (PGPTs) are introduced that decouple photoresponse and charge transport by using wide‐bandgap metal halide perovskites (MHPs) as dielectric layers and non‐wide‐bandgap semiconductors as channels. This design offers material flexibility, simplified processing, and enhanced performance. Using the 2D Ruddlesden‐Popper perovskite PEA 2 PbBr 4 (E g = 3.0 eV) as the dielectric layer and the organic semiconductor (OSC) P3HT as the channel layer, UV phototransistors are successfully achieved with exceptional photodetection performance at operating voltages below 2 V, exhibiting a responsivity of 1960 mA W −1 , a specific detectivity of 3 × 10 11 Jones, and a response time of ≈20 ms. Fabricated via low‐temperature (≤100 °C) solution processing, this approach facilitates scalable production and is adaptable to various OSCs and other wide‐bandgap MHP dielectrics, such as PEA 2 PbCl 4 (E g = 3.6 eV) and PEA 2 SnI 4 (E g = 3.8 eV), extending their potential for DUV detection. As a proof‐of‐concept, an optical decoder for telecommunications is demonstrated using DUV PEA 2 PbCl 4 /PDVT‐10 PGPTs, which are immune to ambient light interference. Additionally, these DUV phototransistors show potential for latent fingerprint detection due to their sensitivity to skin absorption characteristics.