Chiral polar metal halides can generate spontaneous polarization, endowing them with potential for self-driven circularly polarized light (CPL) detection. However, most chiral metal halides crystallize in non-polar space groups and cannot generate spontaneous polarization, making efficient self-driven CPL detection difficult. In this work, for the first time, we propose a strategy to induce spontaneous polarization into non-polar chiral halides by introducing free halogens into the halide lattice via a solvothermal method. We find that this strategy not only breaks the intrinsic symmetry of non-polar R/S-MPZPbBr₄ and transforms it into R/S-MPZPbBr₄·0.5Br₂ with the polar space group C2, but also induces larger octahedral distortion, which enhances the circular dichroism anisotropy factor (g_CD) by 8 times. Benefiting from spontaneous polarization and the enhanced g_CD, R/S-MPZPbBr₄·0.5Br₂ exhibits an anomalous photovoltaic effect of 3.8 V under zero bias and enables efficient self‑driven CPL detection, with an anisotropic response factor (g_res) as high as 0.61. Our work opens a new pathway for designing chiral metal halides for self‑driven CPL detection.

The piezotronics effect utilizes a piezopotential to modulate and control current in piezo-semiconductors. Ferroelectric materials, as a type of piezoelectric materials, possess piezoelectric coefficients that are significantly larger than those found in conventional piezoelectric materials. Here, we propose a strain modulated ferroelectric field-effect transistor (St-FeFET) utilizing external strain instead of gate voltage to achieve ferroelectric modulation, which eliminates the need for gate voltage. By applying a very small strain (0.01%), the St-FeFET can achieve a maximum on-off current ratio of 1250% and realizes a gauge factor (GF) of 1.19 × 10⁶, which is much higher than that of conventional strain sensors. This work proposes a new method for realizing highly sensitive strain sensors and presents innovative approaches to the operation methods of ferroelectric field-effect transistors as well as potential applications for coupling of strain sensors and various devices across different fields.

Visualization is a direct, efficient, and simple interface method to realize the interaction between human and machine, whereas the flexible display unit, as the major bottleneck, still deeply hinders the advances of wearable and virtual reality devices. To obtain flexible optoelectronic devices, one of the effective methods is to transfer a high-efficient and long-lifetime inorganic optoelectronic film from its rigid epitaxial substrate to a foreign flexible/soft substrate. Additionally, piezo-phototronic effect is a fundamental theory for guiding the design of flexible optoelectronic devices. Herein, we demonstrate a flexible, stretchable, and transparent InGaN/GaN multiple quantum wells (MQWs)/polyacrylamide (PAAM) hydrogel-based light emitting diode coupling with the piezo-phototronic effect. The quantum well energy band and integrated luminous intensity (increased by more than 31.3%) are significantly modulated by external mechanical stimuli in the device. Benefiting from the small Young's modulus of hydrogel and weak Van der Waals force, the composite film can endure an extreme tensile condition of about 21.1% stretching with negligible tensile strains transmitted to the InGaN/GaN MQWs. And the stable photoluminescence characteristics can be observed. Moreover, the hydrogen-bond adsorption and excellent transparency of the hydrogel substrate greatly facilitate the packaging and luminescence of the optoelectronic device. And thus, such a novel integration scheme of inorganic semiconductor materials and organic hydrogel materials would help to guide the robust stretchable optoelectronic devices, and show great potential in emerging wearable devices and virtual reality applications.