Controllable growth of two‐dimensional molecular crystals for high‐performance hybrid heterostructure imaging device

In optoelectronic molecular systems, device performance relies critically on the efficiency of exciton transport and relaxation processes. However, conventional organic thin films typically suffer from impurity‐induced traps and nonradiative recombination, which limit efficient exciton utilization and restrict photoconversion efficiency in devices. To address this challenge, we grow layer‐controlled two‐dimensional (2D) perylene‐derivative molecular crystals with strong optical responses by van der Waals (vdW) vapor‐phase epitaxy. Such crystals exhibit near‐unity photoluminescence quantum yields, indicating highly efficient excitonic emission. The integration with transition metal dichalcogenides (TMDCs) forms hybrid organic–inorganic heterostructures where the carrier relaxation can be tunable from charge transfer to Förster resonance energy transfer (FRET). By harvesting FRET, photodetector responsivity and specific detectivity are improved by approximately three and four orders of magnitude, respectively, relative to pristine TMDCs, with reliable single‐pixel imaging capability. These 2D perylene‐derivative crystals provide an ideal materials platform for constructing hybrid vdW heterostructures for integrated on‐chip optoelectronic devices and imaging applications.