As attractive photoactive materials, metal halide perovskites demonstrate outstanding performance in a wide range of optoelectronic applications. Among the various compositions studied, mixed-halide perovskites have a finely tunable band gap that renders them desirable for targeted applications. Despite their advantages, photoinduced halide segregation often deters the photoelectric stability of the materials. Herein, we adopt a strategy of post-treating the perovskite surface with an organic spacer to generate a two-dimensional (2D) perovskite passivating layer. Trap-assisted recombination pathways can be selectively modulated by passivating the surface halide defects that cause photoinduced halide segregation. Fluorescence lifetime imaging of flat and bent surfaces of perovskites reveals that the perovskite lattice tolerates mechanical strain via the neutralizing passivation of ionic halide defects. Upon bending, the photocurrent response of the flexible photodetector is maintained over 83% for 2D passivated perovskite and drops to 23% for pristine perovskite. A flexible photodetector array built with 2D passivated perovskite, in combination with a deep learning algorithm, demonstrates excellent accuracy in determining letters of the alphabet for both flat (>96%) and bent (>93%) states. The connection of chemically modified charge carrier dynamics and mechanical properties revealed in this study offers valuable guidance for developing next-generation optoelectronic applications.

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With the growing interest in wearable devices in recent decades, considerable effort has been devoted to developing mechanical elastomeric devices such as sensors, transistors, logic circuits, and integrated circuits. To successfully implement elastomeric devices subjected to large mechanical deformations or stretching, all the components, including conductors, semiconductors, and dielectrics, must have high stability and mechanical sustainability. Elastomeric conductors, which exhibit excellent electrical performances under mechanical deformations, are key components of elastomeric devices. Herein, we prepared fully elastomeric electrodes based on interconnected 2D gold nanosheets (AuNSs) to develop mechanically resilient integrated electronics. The AuNS elastomeric electrodes exhibited a sheet resistance of less than 2 Ω/sq under 50% stretching and sustained 100,000 stretching–releasing cycles. These electrodes with a dedicated design were used in combination with elastomeric semiconductors of P3HT nanofibrils in the PDMS elastomer (P3NF/PDMS) and an ion gel as a dielectric to realize elastomeric transistors, inverters, and NOR and NAND logic gates. Additionally, an elastomeric 8 × 8 transistor array that can sustain various types of mechanical stimuli was successfully demonstrated. Furthermore, the elastomeric electronic devices implemented on a soft robot showed no interfering performances during robot gripping motion. The proposed framework is expected to aid in the rapid development and broaden the application scope of soft electronics.

This study sampled endangered species, Lamprotula coreana, and surveyed its habitat at the Guem River with three times from June to August 2013. To assess the habitat, this study conducted field survey considering diverse physical conditions of stream, such as pool, run and riffle, and measured transect, water depth, water velocity, substrate structure, and habitat type. When L. coreana collected, length, weight and age were measured. Water velocity, water depth and substrate structure were recorded to develop HSI (habitat suitability index) and performed PHABSIM (physical habitat simulation) to estimate the optimum flow discharge. Water level, flow discharge and transect data were used for habitat assessment, and PHABSIM was applied to calculate WUA (weighed usable area). Shell length was 73.1 ± 18.4 mm (28.5-102.0 mm), shell weight was 131.6 ± 72.3 g (28.0-281.0 g) and age was two to seven years from L. coreana collected at the upstream of the Guem River. Developed HSI indicated that the optimal habitat for L. coreana was 0.4-0.5 m for water depth, 0.3-0.5 m/s for water velocity and sand to boulder for substrate structure. The optimum ecological flow discharge for L. coreana was 2.1 cms and WUA was 3,730 m 2 /1000 m by the result of PHABSIM. Recently, river construction work and habitat disturbance have caused negative impact on the distribution of L. coreana. The result of this study would provide fundamental data for habitat restoration and management of L. coreana.