Perovskite photodetectors have attracted much research and attention because of their outstanding photoelectric characteristics, such as good light harvesting capability, excellent carrier migration behavior, tunable band gap, and so on. Recently, the reported studies mainly focus on materials synthesis, device structure design, interface engineering and physical mechanism analysis to improve the device characteristics, including stability, sensitivity, response speed, device noise, etc. This paper systematically summarizes the application fields and device structures of several perovskite photodetectors, including perovskite photoconductors, perovskite photodiodes, and perovskite phototransistors. Moreover, based on their molecular structure, 3D, 2D, 1D, and 0D perovskite photodetectors are introduced in detail. The research achievements and applications of perovskite photodetectors are summarized. Eventually, the future research directions and main challenges of perovskite photodetectors are prospected, and some possible solutions are proposed. The aim of the work is to provide a new thinking direction for further improving the performance of perovskite photodetectors.

Nucleic acid aptamers, selected through the Systematic Evolution of Ligands by Exponential Enrichment (SELEX), are short nucleic acid sequences that exhibit high affinity and specificity towards diverse targets. Over the past three decades, substantial advancements have been made in both the technology and applications of nucleic acid aptamers. This review provides an in-depth analysis of the historical development and defining characteristics of aptamers, highlighting recent technological innovations in SELEX, including Capillary Electrophoresis SELEX, Microfluidic SELEX, Cell-SELEX, and others. We explore the applications of aptamers in therapeutic and targeted drug delivery, emphasizing their advantages over traditional antibodies such as cost-effectiveness, ease of synthesis, and lower immunogenicity. Key challenges such as stability, specificity, and efficient delivery are discussed, with proposed strategies for improvement including advanced chemical modifications and integration with nanotechnology. By integrating advanced technologies, aptamers hold significant promise for enhancing precision medicine and personalized therapeutic interventions, offering new avenues for the treatment of complex diseases.

Lead-free double perovskite Cs₂AgBiX₆ (X = Cl or Br), as an environmentally friendly alternative to lead-based perovskite, has recently received much attention due to its excellent optoelectronic properties and potential applications. In this study, Li⁺ doped Cs₂AgBiCl₆ crystals are synthesized by heat-assisted solution evaporation. The crystal structure characteristics, component analysis and optical performances are investigated experimentally. Theoretically, the influence of Li⁺ doping on band structure and density of state is explored further by using density functional theory (DFT). It is found that obtained Cs₂Li_xAg_1−xBiCl₆ crystals exhibit typical double perovskite structure, and Li⁺ doping induces slight lattice contraction accompanied with the partial substitution of Ag⁺, and improves the photoluminescence (PL) emission. Additionally, the theoretical calculation indicates that Li⁺ doping can make the band gap increase, introduce deep energy levels into valence band (VB) and conduction band (CB), and meanwhile probably change the transition route to the allowed radiative recombination. These doped lead-free double perovskite materials have potential applications in optoelectronic devices due to their improved optical properties.

In the current study, Cu₂ZnSnS₄ (CZTS) thin film was successfully fabricated by the facile nanocrystals (NCs)-printing approach combined with rapid thermal annealing (RTA) process. Firstly, the CZTS NCs were synthesized by a thermal solution method and the possible formation mechanism was analyzed briefly. Then the influences of RTA toleration temperature and duration time on the various properties of as-printed thin films were examined via XRD, Raman, FE-SEM, UV-vis-IR spectroscopy, EDS and XPS treatments in detail. As observed, the RTA factors of temperature and time had significant impacts on the structure and morphology of as-prepared thin films, while there were no obvious effects on the band gap energy in studied conditions. The results showed that the obtained thin film at optimal RTA conditions of (600 °C, 20 min) featured a kesterite structure in pure phase and an irregular morphology consisting of large grains. Moreover, the satisfactory composition of a Cu-poor, Zn-rich state and an ideal band gap energy of 1.4 eV suggests that as-fabricated CZTS thin film is a suitable light-absorbing layer candidate for the application in thin film solar cells.

Lead-free halide double perovskite Cs₂AgInCl₆ has been extensively studied in recent years due to the lead toxicity and poor stability of common lead halide perovskites. In this study, sodium (Na⁺) and bismuth (Bi³⁺) doped into Cs₂AgInCl₆ double perovskite, then Cs₂Ag_1−xNa_xIn_1 − yBi_yCl₆ films with broadband warm-yellow emissions were achieved by the blade coating method. Herein, Na and Bi content were changed as variables at a series of parameter optimization experiments, respectively. In the Cs₂Ag_1−xNa_xIn_1 − yBi_yCl₆ systems, Na⁺ broke the parity-forbidden transition of Cs₂AgInCl₆, and Bi³⁺ suppressed non-radiative recombination. The partial replacement of Ag⁺ with Na⁺ ions and doping with Bi³⁺ cations were crucial for increasing the intensity of the PL emission. The experimental results showed that the photoluminescence quantum yield of the Cs₂Ag_0.4Na_0.6In_0.8Bi_0.2Cl₆ film was 66.38%, which was the highest data among all samples. It demonstrated remarkable stability under heat and ultraviolet conditions. After five thermal cycles, the PL intensity of the Cs₂Ag_0.4Na_0.6In_0.8Bi_0.2Cl₆ film is only reduced to approximately 5.7% of the initial value. After 720 h continuous ultraviolet irradiation, there occurred 31.9% emission decay of the film.

We present a proposal to enhance the cross-Kerr coupling between the cavity and the mechanical oscillator significantly. Specifically, the periodic modulation of the mechanical spring constant induces strong mechanical parametric amplification, which leads to the cross-Kerr nonlinear enhancement. Also, we discuss its application in photon-phonon blockade and phonon-number measurement. We find that under the strong cross-Kerr coupling condition, not only the photon-phonon blockade effect is dramatically enhanced but also different phonon number is clearly distinguished. Our results offer an alternative approach to perform quantum manipulation between photon and phonon.