Printed High‐Density and Flexible Photodetector Arrays via Size‐matched Heterogeneous Micro‐/Nanostructure

Abstract Semiconductor/metal binary systems constitute the core components in electronic/photonic devices. The domain size of the heterostructure should be comparable to the charge diffusion length for superior photoelectric response. However, the fabrication of size‐matched heterostructures is still a challenge, especially for printed devices. Here, a high‐density photodetector array with lateral semiconductor/metal heterostructure is achieved via the template‐assisted sequentially printing strategy. The Ag/PBDB‐T:ITIC/Ag based lateral heterojunction that matches the charge diffusion length in the charge transfer process provides high light response sensitivity (D* = 3.41 × 10¹² Jones, R = 12.9 A W⁻¹). Moreover, the printed pixel interval can be decreased to 10 µm (10⁶ pixels cm⁻²; resolution: 2.5 × 10³ dpi). As the printing strategy can be implemented on soft substrates, the photodetector arrays are endowed with the flexibility. This work demonstrates a simple and effective strategy for chip‐scale fabrication of flexible high‐performance photodetectors, which validates the potential of printed heterogeneous micro‐/nanostructures for integrated active electronics and optics.