Optical microlithography of perovskite quantum dots/organic semiconductor heterojunctions for neuromorphic photosensors

Heterojunctions of perovskite quantum dots (QDs) and organic semiconductors (OSCs) can synergistically leverage the unique optoelectronic properties of different functional components to fabricate advanced optoelectronic devices, such as neuromorphic photosensors, by low-cost solution processes. However, a long-lasting challenge remains in micropatterning high-density perovskite QDs/polymer OSCs heterojunction array with high yield and reliability due to the fragility of functional layers to organic solvents. High-density and micro-structure patterned organic neuromorphic photosensor arrays based on OSCs and QDs are thus rarely reported. Here, an effective cross-linking microlithography strategy is reported to fabricate perovskite QDs/OSCs microstructure arrays. The fabricated CsPbBr${}_3$ QDs/(poly(2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl) thieno [3,2-b] thiophene) (DPPDTT) planer heterojunctions phototransistor array presents minor device-to-device variation, high density (6500 devices cm${}^{-2}$), and high yield (almost 100%). The device array exhibits impressive merits as a neuromorphic photosensor, including a photosensitivity of 3.02 × 10${}^7$, a responsivity up to 1.92 × 10${}^4$ A W${}^{-1}$, a detectivity exceeding 10${}^{14}$ Jones, and a persistent photoconductivity. Moreover, an energy consumption as low as 27.9 aJ is achieved at an operating voltage of -0.0001 V. The potential application of the heterojunction neuromorphic photosensor array in motion perception is demonstrated in conjunction with a neural network. (© 2024 Wiley‐VCH GmbH)