Yingying Xu,Xiaojin Huang,Yulan Wang,Weiyu Qu,Weiliang Guo,Bin Su,Zhihui Dai
One-dimensional molecular crystal waveguide (MCW) can transmit self-generated electrochemiluminescence (ECL), but heavy optical loss occurs because of the small difference in the refractive index between the crystal and its surroundings. Herein, we report a micropipette electrode-supported MCW (MPE/MCW) for precisely controlling the far-field transmission of ECL in air with a low optical loss. ECL is generated from one terminal of the MCW positioned inside the MPE, which is transmitted along the MCW to the other terminal in air. In comparison with conventional waveguides on solid substrates or in solutions, the MPE/MCW is propitious to the total internal reflection of light at the MCW/air interface, thus confining the ECL efficiently in MCW and improving the waveguide performance with an extremely low-loss coefficient of 4.49 × 10–3 dB μm–1. Moreover, by regulation of the gas atmosphere, active and passive waveguides can be resolved simultaneously inside MPE and in air. This MPE/MCW offers a unique advantage of spatially controlling and separating ECL signal readout from its generation, thus holding great promise in biosensing without or with less electrical/chemical disturbance.
Single-crystal halide perovskites are among the most promising semiconductor candidates for highly efficient optoelectronic devices due to their higher stability against moisture and light radiation and lower trap density than their polycrystalline counterparts. In this work, single-crystal MAPbBr 3 microcavities with controllable geometries and sizes are fabricated using a template-limited method combined with an anti-solvent diffusion growth method. The single-crystal microcavities emit lasers around 550 nm under femtosecond laser excitation, with a lasing threshold of ≈35 µJ cm −2 and a quality factor of 1135, as well as excellent long-term operation stability. The temporal-spatial evolution of the lasing process in an individual microcavity is achieved by the microscopic optical Kerr-gating technique. The temporal behaviors including pulse duration and build-up time, emission spectra shift, and lasing mode evolution as a function of pump fluence are unveiled, and the complex relationship between the light-induced carrier dynamics and lasing properties is clarified. Spatial heterogeneous lasing dynamics are also observed in an individual microdisk, which is attributed to the non-uniform optical losses and carrier densities driven by structural imperfections. This study can provide a fabrication strategy for perovskite on-chip optoelectronic devices, as well as a deeper understanding of the carrier-density-driven lasing dynamics in microcavities.
Meina Song,Yangyang Dang,Jie Dong,Xiaotao Zhang,Shengbin Lei,Wenping Hu
Lanthanide-based coordination polymers (CPs) have received great attention due to their tuneable structures and excellent luminescence properties. However, limited by the stability and micro/nanoscale morphology, a very small number of lanthanide-based CPs have been used for photonic applications. Herein, we present the synthesis of Eu-based CPs (compound 2) with highly regular one-dimensional (1D) microrod morphology by in situ structure transformation from compound 1. Moreover, the Eu-based CP microrods have an excellent stability and a high photoluminescence quantum yield (PLQY), and the distance-dependent PL spectra also exhibited typical characteristics of photoactive waveguides with a low optical-loss coefficient (0.00894 dB μm−1) during propagation. These intriguing behaviors not only extend the research field of optical waveguides through lanthanide-based CPs, but also provide an opportunity for further application in optical communication systems.
2D microstructures of N′N′-diphenyl-N,N′-bis(1-naphthyl)-1,1'-biphenyl-4,4'-di-amine (NPB) have been prepared by a facile solution method and fully characterized. The as-prepared NPB microsheets have well-defined shapes and very smooth surfaces, and are
ideal building blocks for 2D optical waveguides. The results indicate that the optic losses within NPB microsheets are closely related to the direction of propagation, and the shape of microsheets can change the direction of waveguiding light. Such 2D optical waveguides may have potential
applications in future miniaturized light-based circuits serve as interconnectors different from 1D optical waveguides.
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