Ultra-thin and flexible silicon chips are pivotal for high-performance conformal electronics. Backside grinding reduces chip thickness below 50 μm, enabling mass production of ultra-thin flexible chips in a low-cost way, yet the resulting defects and residual stress on the backside may propagate to the frontside circuits degrading the electric performance, especially for the critical-thickness devices. Here, commercial pulse-width modulation (PWM) chip wafers (involving tens of thousands of dies) based on bipolar transistors have been thinned to the thickness of ~ 20 μm by mechanical grinding with different parameters. Experimental results reveal a thickness-dependent bifurcated failure mechanism: Short-circuit current decays progressively with thickness reduction, while leakage current exhibits a catastrophic surge below the critical thickness (~ 18 μm). This work reveals a dual degradation mechanism in ultrathin ICs: Mechanical grinding not only amplifies substrate parasitic coupling via geometric thinning but also generates stress fields that induces dislocation rearrangement-aggregation cascades, ultimately dictating electrical failure modes. Chemical mechanical polishing (CMP) and reactive ion etching (RIE) have been deployed to inhibit leakage current surges by removing grinding-induced damaged layers and relieving interfacial residual stress, which collectively validate the stress-defect interaction as the governing mechanism of electrical failure in ultra-thin chips (UTCs). Hopefully, this study can throw light on the impact of mechanical grinding thinning on the electrical performance of ultra-thin chips paving the way to the wide applications of high-performance flexible electronics in the future.

Flexible pressure sensor empowers the perception of external mechanical stimuli with flexible electronics. The adequate alignment between the sensor's operation characteristics and the application scenarios is crucial for maximizing performance. Achieving the configuration of sensitivity and response threshold within single device framework is expected to significantly enhance the versatility of flexible pressure sensor across a variety of applications. In this work, we present a synergistic structural design (SSD) for flexible iontronic pressure sensor to facilitate on‐demand configuration of device characteristics. By incorporating a customizable spacer gasket structure and an interlocked microstructure within the ionic gel, the response threshold can be adjusted to cover both small‐pressure detection and large operational ranges. With the rational SSD configuration, the SSD‐based sensor achieves a sensitivity reaching up to 1478.8 kPa⁻¹, along with a tunable response threshold from 11.2 Pa to over 400 kPa. We demonstrate the potential of the SSD‐based sensor for diverse human interactions applications. Furthermore, a scalable array of the SSD‐based sensor units enables multitouch pressure mapping. The SSD approach provides a versatile strategy for tailoring the characteristics of flexible pressure sensor to meet varying application needs.

At present, the performances of perovskite solar cells (PSCs) are comparable to that of crystalline silicon solar cells, but their relatively poor stabilities are not conducive to industrial application. In this paper, the factors causing the instabilities of perovskite nanocrystals and the main strategies to improve the stability of corresponding solar cells are introduced, while the latest research progresses of organosilicon in PSCs are evaluated. The influence mechanism of silane coupling agent, silicone resin and other organosilicon molecules on the properties of perovskite films (such as morphology, trap state density, carrier transport and ion migration, etc.) and the performances of devices (such as power conversion efficiency and stability, etc.) will be discussed in detail. Finally, the development trend of self-crosslinked organosilicon materials in efficient and stable PSCs are prospected, aiming to provide reference for accelerating the industrialization of PSCs.

The successful implementation of bioelectronic devices attached to living organism hinges on a number of material and device characteristics, including not only electrical and mechanical performances to gather physiological signals from living organism thus enabling status monitoring, but also permeability or breathability for gas/nutrient exchange between living organisms and surroundings to ensure minimum perturbation of the intrinsic biological function. However, most bioelectronic devices built on planar polymeric substrates, such as polydimethylsiloxane (PDMS), polyurethane (PU), and polyimide (PI), lack efficient gas permeability, which may hinder the emission of volatile compounds from the surface of living organism, affecting the natural metabolism and reducing the comfort of wearing. Thus, achieving permeability or breathability in bioelectronic devices is a significant challenge. Currently, the devices made of gas-permeable materials with porous structures, that combine electronic components with daily garments, such as fibric and textile, offer exciting opportunities for breathable electronics. In this review, several types of gas-permeable materials with their synthesis and processing routes are outlines. Then, two methods for measuring water vapor transmission rate of materials are discussed in depth. Finally, recent progress in the use of gas-permeable materials for the applications of plant- and skin-attached electronics is summarized systematically.