Structural Optimization of BODIPY Derivatives: Achieving Stable and Long-Lived Green Emission in Hyperfluorescent OLEDs

Boron dipyrromethene (BODIPY) derivatives are widely studied as terminal emitters in organic light-emitting diodes (OLED) due to their narrow emission and high photoluminescence quantum yield (PLQY). However, the strategy for precisely tuning their emission toward a high color purity is still challenging. Herein, we developed a new design strategy to regulate the emission of BODIPY derivatives by modifying the electronic and steric dominance using functionalities, such as nitrile, pentafluorophenyl, diethyl, and monobenzyl. These rational modifications yielded a series of four novel green BODIPY emitters, namely, tPN-BODIPY, tPPP-BODIPY, tPBn-BODIPY, and tPEN-BODIPY, each benefited with a tuned emissions range of 517 to 542 nm with a narrow fwhm of 25 nm and high photoluminescence quantum yield up to 96%. Among these synthesized BODIPYs, an unsymmetrical tPBn-BODIPY was chosen as a final dopant (FD) to explore its application in OLED devices. The fabricated TADF sensitized fluorescence-OLED (TSF-OLED) exhibits a narrow band pure green emission at 531 nm with corresponding CIE coordinates of (x, y) = (0.27, 0.68) and a maximum external quantum efficiency (EQE) of 20%. Furthermore, the TSF-OLED displayed an exceptionally prolonged device operational lifetime (LT90) of 210 h at an initial luminescence of 3000 cd m-2.

Advanced Light Source Technologies for Photodynamic Therapy of Skin Cancer Lesions

Photodynamic therapy (PDT) is an increasingly popular dermatological treatment not only used for life-threatening skin conditions and other tumors but also for cosmetic purposes. PDT has negligible effects on underlying functional structures, enabling tissue regeneration feasibility. PDT uses a photosensitizer (PS) and visible light to create cytotoxic reactive oxygen species, which can damage cellular organelles and trigger cell death. The foundations of modern photodynamic therapy began in the late 19th and early 20th centuries, and in recent times, it has gained more attention due to the development of new sources and PSs. This review focuses on the latest advancements in light technology for PDT in treating skin cancer lesions. It discusses recent research and developments in light-emitting technologies, their potential benefits and drawbacks, and their implications for clinical practice. Finally, this review summarizes key findings and discusses their implications for the use of PDT in skin cancer treatment, highlighting the limitations of current approaches and providing insights into future research directions to improve both the efficacy and safety of PDT. This review aims to provide a comprehensive understanding of PDT for skin cancer treatment, covering various aspects ranging from the underlying mechanisms to the latest technological advancements in the field.

Photoactive CuI-Cross-Linked Polyurethane Materials

Using multinuclear copper iodide complexes as cross-linking agents in a polyurethane matrix, original photoluminescent stimuli-responsive materials were synthesized. The intrinsic photoluminescence properties of the covalently incorporated copper iodide complexes are thus transferred to the materials while retaining the beneficial characteristics of the polymer host. The transparent materials exhibit room-temperature phosphorescence with emission switching properties by displaying luminescence thermochromism and solvatochromism. The luminescence thermochromism is characterized by a change in the wavelength and intensity of the emission with temperature, and the vapochromic effect presents a contrasted response of extinction or exaltation according to the nature of the solvent of exposure. By combining the luminescence characteristics of photoactive copper iodide complexes with the ease of polymer processing, the application of these luminescent materials as phosphors in LED (light-emitting diode) devices was also demonstrated. The present study shows that the use of copper iodide complexes as cross-linkers in polymeric materials is a relevant strategy to design materials with enhanced functionalities in addition to their low cost and sustainable characteristics.

Wood-Derived Carbon Materials and Light-Emitting Materials

Wood is a sustainable and renewable material that naturally has a hierarchical structure. Cellulose, hemicellulose, and lignin are the three main components of wood. The unique physical and chemical properties of wood and its derivatives endow them with great potential as resources to fabricate advanced materials for use in bioengineering, flexible electronics, and clean energy. Nevertheless, comprehensive information on wood-derived carbon and light-emitting materials is scarce, although much excellent progress has been made in this area. Here, the unique characteristics of wood-derived carbon and light-emitting materials are summarized, with regard to the fabrication principles, properties, applications, challenges, and future prospects of wood-derived carbon and light-emitting materials, with the aim of deepening the understanding and inspiring new ideas in the area of advanced wood-based materials.

Wood-Derived Carbon Materials and Light-Emitting Materials

Wood is a sustainable and renewable material that naturally has a hierarchical structure. Cellulose, hemicellulose, and lignin are the three main components of wood. The unique physical and chemical properties of wood and its derivatives endow them with great potential as resources to fabricate advanced materials for use in bioengineering, flexible electronics, and clean energy. Nevertheless, comprehensive information on wood-derived carbon and light-emitting materials is scarce, although much excellent progress has been made in this area. Here, the unique characteristics of wood-derived carbon and light-emitting materials are summarized, with regard to the fabrication principles, properties, applications, challenges, and future prospects of wood-derived carbon and light-emitting materials, with the aim of deepening the understanding and inspiring new ideas in the area of advanced wood-based materials.

New Synthetic Approaches to N-Aryl and π-Expanded Diketopyrrolopyrroles as New Building Blocks for Organic Optoelectronic Materials

Diketopyrrolopyrrole (DPP) as a building block has been intensively investigated for organic semiconductors and light emitting materials. The synthesis of N-aryl DPPs remains challenging. Herein, we firstly report a new easily handled synthetic method toward N-aryl DPPs through H-DPP with diaryliodonium salt in the presence of CuI, which shows broad reaction scope. Sixteen N-aryl DPPs, including phenyl, furan and thiophene as flanking aromatic groups, were synthesized with yields up to 78 %. These N-aryl DPPs are fluorescent in both solutions and solid states, with quantum yields up to 96 % and 40 %, respectively. Moreover, we show that the reaction between H-DPP and diaryliodonium salt can lead to π-expanded DPPs by using Pd(OAc)₂ as catalyst. Nine π-expanded DPPs were obtained in 27-61 % yields. These π-expanded DPPs exhibit good semiconducting properties with hole mobility of 0.71 cm²  V^-1  s^-1 , demonstrating that they are useful building blocks for high performance organic semiconductors.

Terpyridine-Containing π-Conjugated Polymers for Light-Emitting and Photovoltaic Materials

2,2':6',2″-Terpyridine (tpy) is a versatile moiety used in the construction of small novel molecules or polymers. Extending or coupling tpy with π-conjugation structures can result in interesting optoelectronic properties. This mini-review summarizes the significant progress made over the past decades in the study of tpy-containing π-conjugated polymers and their application in light-emitting and photovoltaic materials. When coordinated with metal ions, tpy exhibits immense potential for the synthesis of metallo-supramolecular or metallo-polymer materials. Therefore, tpy-based metallo-polymers are the primary focus of this study. Selected examples will be reviewed with a special emphasis on the properties of these functional systems, which can consequently help further their application in light-to-electricity or electricity-to-light conversion fields.

Perovskites for Light Emission

Next-generation displays require efficient light sources that combine high brightness, color purity, stability, compatibility with flexible substrates, and transparency. Metal halide perovskites are a promising platform for these applications, especially in light of their excellent charge transport and bandgap tunability. Low-dimensional perovskites, which possess perovskite domains spatially confined at the nanoscale, have further extended the degree of tunability and functionality of this materials platform. Herein, the advances in perovskite materials for light-emission applications are reviewed. Connections among materials properties, photophysical and electrooptic spectroscopic properties, and device performance are established. It is discussed how incompletely solved problems in these materials can be tackled, including the need for increased stability, efficient blue emission, and efficient infrared emission. In conclusion, an outlook on the technologies that can be realized using this material platform is presented.

High-Performance Organic Electroluminescence: Design from Organic Light-Emitting Materials to Devices

Organic electroluminescence is considered as the most competitive alternative for the future solid-state displays and lighting techniques owing to many advantages such as self-luminescence, high efficiency, high contrast, high color rendering index, ultra-thin thickness, transparency, flat and flexibility, etc. The development of high-performance organic electroluminescence has become the continuing focus of research. In this personal account, a brief overview of representative achievements in our study on the design of highly efficient novel organic light-emitting materials (including fluorescent materials, phosphorescent iridium(III) complexes and conjugated polymers bearing phosphorescent iridium(III) complex) and high-performance device structures together with working principles are given. At last, we will give some perspectives on this fascinating field, and also try to provide some potential directions of research on the basis of the current stage of organic electroluminescence.