Next-generation polarized mid-infrared imaging systems generally requires miniaturization, integration, flexibility, good workability at room temperature and in severe environments, etc. Emerging two-dimensional materials provide another route to meet these demands, due to the ease of integrating on complex structures, their native in-plane anisotropy crystal structure for high polarization photosensitivity, and strong quantum confinement for excellent photodetecting performances at room temperature. However, polarized infrared imaging under scattering based on 2D materials has yet to be realized. Here we report the systematic investigation of polarized infrared imaging for a designed target obscured by scattering media using an anisotropic tellurium photodetector. Broadband sensitive photoresponse is realized at room temperature, with excellent stability without degradation under ambient atmospheric conditions. Significantly, a large anisotropic ratio of tellurium ensures polarized imaging in a scattering environment, with the degree of linear polarization over 0.8, opening up possibilities for developing next-generation polarized mid-infrared imaging technology.

Memory and logic in the same device Future artificial intelligence applications and data-intensive computations require the development of neuromorphic systems beyond traditional heterogeneous device architectures. Physical separation between a peripheral signal-processing unit and a memory-operating unit is one of the main bottlenecks of heterogeneous architectures, blocking further improvements in efficient resistance matching, energy consumption, and integration compatibility. Tong et al . present a transistor-memory architecture based on a homogeneous tungsten selenide-on-lithium niobate device array (see the Perspective by Rao and Tao). Analog peripheral signal preprocessing and nonvolatile memory were possible within the same device structure, promising diverse neuromorphic functionalities and offering potential improvements in neuromorphic systems on-chip. —YS

Perovskite semiconductor nanocrystals with different compositions have shown promise for applications in light-emitting devices. Dark excitonic states may suppress light emission from such nanocrystals by providing an additional nonradiative recombination channel. Here, we study the composition dependence of dark exciton dynamics in nanocrystals of lead halides by time-resolved photoluminescence spectroscopy at cryogenic temperatures. The presence of a spin-related dark state is revealed by magneto-optical spectroscopy. The energy splitting between bright and dark states is found to be highly sensitive to both halide elements and organic cations, which is explained by considering the effects of size confinement and charge screening, respectively, on the exchange interaction. These findings suggest the possibility of manipulating dark exciton dynamics in perovskite semiconductor nanocrystals by composition engineering, which will be instrumental in the design of highly efficient light-emitting devices.