Contactless User-Interactive Sensing Display for Human-Human and Human-Machine Interactions.

Creating a large-scale contactless user-interactive sensing display (CUISD) with optimal features is challenging but crucial for efficient human-human or human-machine interactions. This study reports a CUISD based on dynamic alternating current electroluminescence (ACEL) that responds to humidity. Subsecond humidity-induced luminescence is achieved by integrating a highly responsive hydrogel into the ACEL layer. The patterned silver nanofiber electrode and luminescence layer, produced through electrospinning and microfabrication, result in a stretchable, large-scale, high-resolution, multicolor, and dynamic CUISD. The CUISD is implemented for the real-time control of a remote-controlled car, wherein the luminescence signals induced by touchless finger movements are distinguished and encoded to deliver specific commands. Moreover, the distinctive recognition of breathing facilitates the CUISD to serve as a visual signal transmitter for information interaction, which is particularly beneficial for individuals with disabilities. The paradigm shift depicts in this work is expected to reshape the way authors interact with each other and devices, discovering niche applications in virtual/augmented reality and the metaverse.

Surface Energy-Assisted Patterning of Vapor Deposited All-Inorganic Perovskite Arrays for Wearable Optoelectronics.

Solution-based methods for fabricating all-inorganic perovskite film arrays often suffer from limited control over nucleation and crystallization, resulting in poor homogeneity and coverage. To improve film quality, advanced vapor deposition techniques are employed for continuous film. Here, the vapor deposition strategy to the all-inorganic perovskite films array, enabling area-selective deposition of perovskite through substrate modulation is expanded. It can yield a high-quality perovskite film array with different pixel shapes, various perovskite compositions, and a high resolution of 423 dpi. The resulting photodetector arrays exhibit remarkable optoelectronic performance with an on/off ratio of 13 887 and responsivity of 47.5 A W-1. The device also displays long-term stability in a damp condition for up to 12 h. Moreover, a pulse monitoring sensor based on the perovskite films array demonstrates stable monitoring for pulse signals after being worn for 12 h and with a low illumination of 0.055 mW cm-2, highlighting the potential application in wearable optoelectronic devices.

A Universal Fabrication Strategy for High-Resolution Perovskite-Based Photodetector Arrays.

Metal halide perovskite photodetector arrays have demonstrated great potential applications in the field of integrated systems, optical communications, and health monitoring. However, the fabrication of large-scale and high-resolution device is still challenging due to their incompatibility with the polar solvents. Here, a universal fabrication strategy that utilizes ultrathin encapsulation-assisted photolithography and etching to create high-resolution photodetectors array with vertical crossbar structure is reported. This approach yields a 48 × 48 photodetector array with a resolution of 317 ppi. The device shows good imaging capability with a high on/off ratio of 3.3 × 105 and long-term working stability over 12 h. Furthermore, this strategy can be applied to five different material systems, and is fully compatible with the existing photolithography and etching techniques, which are expected to have potential applications in the other high-density and solvent-sensitive devices array, including perovskite- or organic semiconductor-based memristor, light emitting diode displays, and transistors.

Controlled on-chip fabrication of large-scale perovskite single crystal arrays for high-performance laser and photodetector integration.

Metal halide perovskites possess intriguing optoelectronic properties, however, the lack of precise control of on-chip fabrication of the large-scale perovskite single crystal arrays restricts its application in integrated devices. Here, we report a space confinement and antisolvent-assisted crystallization method for the homogeneous perovskite single crystal arrays spanning 100 square centimeter areas. This method enables precise control over the crystal arrays, including different array shapes and resolutions with less than 10%-pixel position variation, tunable pixel dimensions from 2 to 8 µm as well as the in-plane rotation of each pixel. The crystal pixel could serve as a high-quality whispering gallery mode (WGM) microcavity with a quality factor of 2915 and a threshold of 4.14 µJ cm-2. Through directly on-chip fabrication on the patterned electrodes, a vertical structured photodetector array is demonstrated with stable photoswitching behavior and the capability to image the input patterns, indicating the potential application in the integrated systems of this method.

Large-Scale, Uniform-Patterned CsCu2 I3 Films for Flexible Solar-Blind Photodetectors Array with Ultraweak Light Sensing.

Cesium copper halide perovskite is one of the promising materials for solar-blind light detection. However, most of the cesium copper halide perovskite-based photodetectors (PDs) are focused on ultraviolet A detection and realized on the rigid substrate in the single device configuration. Here, a flexible solar-blind PDs array (10 × 10 pixels) based on the CsCu2 I3 film patterns for ultraweak light sensing and light distribution imaging is reported. Large-scale CsCu2 I3 film arrays are synthesized with various shapes and uniform dimensions through a simple vacuum-heating-assisted solution method. Benefiting from excellent air stability and superior resistance to the photodegrading of the CsCu2 I3 film, the array device exhibits long-term stable photoswitching behavior for 8 h and ultralow light detection capability to resolve the light intensity of 6.1 nW cm-2 with a high responsivity of 62 A W-1 , and the array device can acquire clear images of "G", "X", and "U" showing the input light distribution. Moreover, the flame detection and warning system based on a curved solar-blind PDs array is demonstrated, which can be used for multi-flame monitoring and locating. These results can encourage potential applications of the CsCu2 I3 film-based PDs array in the field of optical communication and environment monitoring.

Recent Progress on Wavelength-Selective Perovskite Photodetectors for Image Sensing.

Spectral sensing plays a crucial part in imaging technologies, optical communication, and other fields. However, complicated optical elements, such as prisms, interferometric filters, and diffraction grating, are required for commercial multispectral detectors, which hampers their advance toward miniaturization and integration. In recent years, metal halide perovskites have been emerging for optical-component-free wavelength-selective photodetectors (PDs) because of their continuously tunable bandgap, fascinating optoelectronic properties, and simple preparation processes. In this review, recent advances in wavelength-selective perovskite PDs, including narrowband PDs, dual-band PDs, multispectral-recognizable PDs, and X-ray PDs, are highlighted, with an emphasis on device structure designs, working mechanisms, and optoelectronic performances. Meanwhile, the applications of wavelength-selective PDs in image sensing for single-/dual-color imaging, full-color imaging, and X-ray imaging are introduced. Finally, the remaining challenges and perspectives in this emerging field are presented.

Ultrathin and Conformable Lead Halide Perovskite Photodetector Arrays for Potential Application in Retina-Like Vision Sensing.

Solution-processed lead halide perovskites are considered one of the promising materials for flexible optoelectronics. However, the array integration of ultrathin flexible perovskite photodetectors (PDs) remains a significant challenge limited by the incompatibility of perovskite materials with manufacturing techniques involving polar liquids. Here, an ultrathin (2.4 µm) and conformable perovskite-based PD array (10 × 10 pixels) with ultralight weight (3.12 g m-2 ) and excellent flexibility, is reported. Patterned all-inorganic CsPbBr3 perovskite films with precise pixel position, controllable morphology, and homogenous dimension, are synthesized by a vacuum-assisted drop-casting patterning process as the active layer. The use of waterproof parylene-C film as substrate and encapsulation layer effectively protects the perovskite films against penetration of polar liquids during the peeling-off process. Benefitting from the encapsulation and ultrathin property, the device exhibits long-term stability in the ambient environment, and robust mechanical stability under bending or 50% compressive strain. More importantly, the ultrathin flexible PD arrays conforming to hemispherical support realize imaging of light distribution, indicating the potential applications in retina-like vision sensing.