Charged quantum dots (QD) coupled to micropillar cavities are key platforms for studying photon-spin interactions. However, most research involves quantum dots charged via external excitation, resulting in short charge lifetimes. We demonstrate a device where a quantum dot confines an extra electron through δ-doping and couples to a high Q-factor (about 11 000) micropillar cavity mode (CM). We propose a precise calibration process for the micropillar cavity to achieve coupling between the negatively charged exciton (X−) transitions and CM at low temperatures. Micro-photoluminescence (μPL) spectroscopy confirms X− transitions and their coupling with CM at 7K, with the coupled emission intensity enhanced about tenfold relative to the uncoupled state. The X− transitions and CM both show low spectral fluctuations at the change of polarization of incident light (X− 2.66 μeV, CM 3 μeV).

To study MEMS power detection chips more accurately, a thermo-electromechanical coupling model is proposed in this work. The fringing capacitance is included in the model, further refining the expression for the parallel-plate capacitance. Moreover, the squeeze-film damping and thermoelastic damping are considered in the second-order differential equation to study the cantilever vibration. It is found that the squeeze-film damping is the dominant damping of the system, and the cantilever beam exhibits linear expansion with increasing temperature. A dual-channel microwave detection chip is fabricated and measured, and the return loss reaches its minimum of -66.46 dB at 9 GHz, indicating optimal impedance matching at the central frequency. Moreover, the measured sensitivity is approximately 65.6 fF/W. Critically, the measured resonant frequency of the cantilever beam is 115.7 kHz, which is orders of magnitude lower than the input signal frequency. This large separation ensures that the sensor operates in a stable, non-resonant regime, thereby guaranteeing linearity and reliability. These findings demonstrate the excellent microwave performance of the power sensor fabricated in this work, providing valuable insights for optimizing the design of MEMS microwave power detection chips.

Sb₂S₃ has attracted increasing attention for next-generation photovoltaics due to its excellent materials and optoelectronic properties, especially a suitable bandgap (~1.75 eV) for indoor photovoltaics and silicon-based tandem solar cells. However, the highest power conversion efficiency (PCE) report thus far for Sb₂S₃ solar cells is 8.26%, lagging far behind its theoretical efficiency limit (~28%). This study aims to scrutinize the important roles of hole transport layers (HTLs) in near-intrinsic Sb₂S₃ solar cells. It is found that the device efficiencies of both of p-type Sb₂S₃ and n-type Sb₂S₃ based planar solar cells are significantly enhanced with the incorporation of Spiro-OMeTAD HTL, further confirmed by the SCAPS simulation. The specific roles of HTL on promoting the interface hole extraction in Sb₂S₃ solar cells are elucidated. Then the performance optimization is conducted by systematically optimizing key parameters of Sb₂S₃ absorbers, such as absorber thickness, defect density, and doping concentration. Furthermore, several typical inorganic HTL candidates for replacing Spiro-OMeTAD were explored for Sb₂S₃ solar cells, revealing that the Cu₂O HTL based device exhibits a highest PCE of 23.09%. This work highlights the necessity of HTLs for devices based on near-intrinsic Sb₂S₃ and provides valuable insights for further enhancing the performance of Sb₂S₃ solar cells.

Integrating electrochromic (EC) and photochromic (PC) functions within a single material system holds great significance for the development of next-generation intelligent responsive materials. Traditional organic photochromic materials are all small molecules and oligomers, which require the photochemical response of specific photosensitive groups. However, PEDOT:PSS, a classic electrochromic polymer, has never been reported to exhibit photochromic properties due to the absence of photosensitive groups. Herein, we report for the first time the photochromic properties of PEDOT:PSS films, demonstrating their simultaneous capability of multi-field coupling response in the aspects of light, electricity and chemistry. The composite film undergoes a rapid color change from light blue to dark blue under ultraviolet light irradiation. This is attributed to the transformation process from the bipolarons state to the polarons state in the PEDOT:PSS, induced by photogenerated electrons as confirmed by EPR and Raman analyses. Furthermore, the developed hydrogel system enhances charge separation, yielding a 30.1% relative transmittance change and month-long stability. This work fills the long-standing gap in the understanding of the photochromic and electrochromic mechanisms of PEDOT:PSS, providing fundamental insights into carrier dynamics at organic-inorganic interfaces and laying the foundation for the development of multi-mode stimuli-responsive devices.