Advanced Optical Materials最新文献

In this study, three stable tetradentate Pt(II) complexes are synthesized and characterized, namely, Pt-biPh, Pt-biPh5tBu, and Pt-biPh4tBu, tailored for blue phosphorescent organic light-emitting diodes to realize high-efficiency and narrowband emissions via ligand engineering. Biphenyl (Pt-biPh) or tert-butyl-modified biphenyl (Pt-biPh5tBu and Pt-biPh4tBu) is introduced into the carbene unit of the ligand to control the intermolecular interactions between the Pt(II) phosphors. Pt-biPh, Pt-biPh5tBu, and Pt-biPh4tBu exhibit high photoluminescence quantum yields of 74%, 84%, and 92% with exciton lifetimes of 2.2, 2.3, and 2.5 µs, respectively, demonstrating rapid and efficient light emission. Furthermore, Pt-biPh, Pt-biPh5tBu, and Pt-biPh4tBu show maximum external quantum efficiency (EQE) values of 18.1%, 19.0%, and 21.8%, respectively. Pt-biPh5tBu and Pt-biPh4tBu exhibit narrowband emission with a full width at half maximum of 21 nm owing to the small vibrational emission because of their sterically hindered and bulky ligand structures. Moreover, phosphor-sensitized thermally activated delayed fluorescence devices employing a Pt-biPh4tBu sensitizer achieve a high EQE of 28.6%. In particular, Pt-biPh4tBu performs better than the state-of-the-art phosphor as the sensitizer of the blue phosphor-sensitized thermally activated delayed fluorescence devices in terms of the EQE.

Optical encryption technology attracts considerable attention in the field of information encryption, information storage, and anti-counterfeiting. However, optical encryption based on conventional on/off mode still faces issues such as low scalability, ease of cracking, and poor storage capacity; multi-dimensional and high storage capacity information encryption systems are thus needed. Herein, a programmable information encryption circuit system is demonstrated by constructing a delay light-emitting diode (LED) array using multi-color phosphorescent carbon nanodots (CNDs) with versatile lifetimes. The CNDs show adjustable luminescence wavelength and lifetime from 192 to 1148 ms. The programmable delay luminescent circuit provides an intricate framework for meticulously integrating an LED array, enabling the creation of intricate patterns or alphanumeric codes. These intricate designs are engineered to serve as a component of an encryption system, which can be deciphered and unveiled under a specific delay time range. This study demonstrates the feasibility and superiority of the system as a new type of information anti-counterfeiting encryption technology, providing a new concept for exploring the field of integrated circuit anti-counterfeiting and encryption.

The introduction of liquid crystals into microcavities has garnered considerable attention for their exceptional tunability and high sensitivity to external perturbation factors within their distinct phase states. Here, a novel light source with both wavelength tunability and an exceptionally narrow linewidth is presented. This innovation is realized by strategically manipulating LC molecules, transitioning them from a well-aligned state to a disordered state with increasing temperature. The microcavity is tailored to support bound states in the continuum, a cutting-edge concept in photonic research that allows for light localization with minimal loss. In the pursuit of potential biocompatibility and to reduce cytotoxicity, indium phosphide colloid quantum dots are opted to serve as the emissive carriers within the system. An ultra-narrow linewidth light emission of 0.039 nm is observed, corresponding to a quality factor reaching 16668, along with a tunable range of 1.21 nm and a temperature sensitivity of 33.52 pm K⁻¹. The invention's compact size and tunable character make it an ideal candidate for a variety of potential applications, such as eco-friendly sensors with minimal ecological impact, optical modulators with precise control over light, and adaptable photonic devices that can be integrated with a diverse array of materials and configurations.

Direct Evidence of Ultrafast Energy Delocalization

Energy delocalization is observed in a strongly coupled cavity containing two layers of donor and acceptor molecules, separated by an inert spacer layer of 2 μm thickness. Margherita Maiuri, Tersilla Virgili, and co-workers (see article number 2400821) use two-dimensional electronic spectroscopy, a technique that provides simultaneously high spectral and temporal resolution, to probe the dynamics of the energy flow processes following ultra-fast excitation. Their finding opens new perspectives on remote photo/induced energy transport useful in advanced optoelectronic devices.

Efficient and stable scintillators play a crucial role in X-ray detection applications. To enhance the luminescence efficiency under X-ray excitation, the incorporation of multiple emission centers into scintillators is widely explored. Here, it is found that the cesium copper halide Cs₅Cu₃Cl₆I₂ exhibits dual emission centers, enabling high-performance scintillators with an X-ray light yield of 49000 photon MeV⁻¹ and a low detection limit of 4 nGy s⁻¹. The emissions of Cs₅Cu₃Cl₆I₂ are from intrinsic self-trapped exciton (STE) and Frenkel defect-assisted STE. High-energy X-rays can induce an increased fraction of Frenkel defect-assisted STEs, which can serve as an effective scintillation channel. Furthermore, large-area flexible scintillators with a high resolution of 18 lp mm⁻¹ are developed, making them suitable for X-ray imaging applications. These findings offer promising insights for developing more efficient scintillators.