Sensitive and Ultrafast Perovskite/Organic Hybrid Photodetectors With a Broad Spectral Response From Ultraviolet to the Telecommunication Band.

Fast and sensitive photodetectors (PDs) with broadband spectral responses are crucial in numerous fields, including image sensing, optical communication, and biochemical applications. While organic PDs offer broadband spectral responses, their response speed is typically limited to the microsecond range. This study demonstrates a sensitive, ultrafast PD with a broad spectral response by combining a 2D perovskite layer with an organic heterojunction of poly[(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b'] dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PTB7-Th) and (2,20-((2Z,20Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2″,30':4',50]thieno[20,30:4,5]pyrrolo[3,2-g]thieno[20,30: 4,5]thieno[3,2-b]indole-2,10-diyl)bis(me-thanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dima-lononitrile) (Y6) as the active layer. The perovskite layer enhances the sensitivity across a wide spectral range due to better absorption at short wavelengths and improves hole mobility. The external quantum efficiency achieves 85% at 335 nm and 72% at 830 nm under a -2 V bias. At 830 nm, the responsivity and detectivity reach 0.5 A W-1 and 2.8 × 1012 Jones, respectively. A large linear dynamic range of 197 dB is observed at 375 nm. Additionally, the response time is significantly reduced to 2.6 ns by decreasing the RC time constant. The hybrid PD also demonstrates a broad spectral response extending up to 1550 nm, attributed to intermolecular charge transfer absorption between PTB7-Th and Y6. This work advances the development of low-cost, broadband, and high-speed PDs for a wide range of applications.