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

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 PEA₂PbBr₄ (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  ×  10¹¹ 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 PEA₂PbCl₄ (E_g = 3.6 eV) and PEA₂SnI₄ (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 PEA₂PbCl₄/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.