Organic near-infrared optoelectronic materials and devices:an overview

Near-infrared(NIR)light has shown great potential for military and civilian applications owing to its advantages in the composition of sunlight,invisibility to human eyes,deeper penetration into biological tissues,and low optical loss in optical fibers.Therefore,organic optoelectronic materials that can absorb or emit NIR light have aroused great scientific interest in basic science and practical applications.Based on these NIR organic optoelectronic materials,NIR optoelectronic devices have been greatly improved in performance and application.In this review,the representative NIR organic optoelectronic materials used in organic solar cells,organic photodetectors,organic light-emitting diodes,organic lasers,and organic optical waveguide devices are briefly introduced,and the potential applications of each kind of device are briefly summarized.Finally,we summarize and take up the development of NIR organic optoelectronic materials and devices.

A New Class of Biodegradable Organic Optoelec-tronic Materials:α-Oligofurans

Organic optoelectronic materials have received considerable attention due to their great potentials in electronic devices,such as organic field-effect transistors(OFETs),organic light-emit-ting diodes(OLED)and organic photovoltaic cells(OPV).Besides,their fascinating properties of flexibility,biocompatibility,molecular diversity,low-cost and solution processability bring new opportunities in bioelectronics in the past decade.While almost all known organic optoelectronic materials are obtained from unrenewable fossil resources and nondegradable,a new family of organic optoelectronic materials is now emerging,which can be obtained from green plants and are biodegradable.Meanwhile,they exhibit excellent optoelectronic properties.This review summarized the synthesis and important molecular properties of this new class of biodegradable organic opto-electronic materials:α-oligofurans.Recent progress of furan-based materials and the existing chal-lenges are also discussed to stimulate further advances in the study of this class of materials.

Near-infrared organic photoelectric materials for lightharvesting systems: Organic photovoltaics and organic photodiodes

The inherent advantages of organic optoelectronic materials endow lightharvesting systems,including organic photovoltaics(OPVs)and organic photodiodes(OPDs),with multiple advantages,such as low-cost manufacturing,light weight,flexibility,and applicability to large-area fabrication,make them promising competitors with their inorganic counterparts.Among them,nearinfrared(NIR)organic optoelectronic materials occupy a special position and have become the subject of extensive research in both academia and industry.The introduction of NIR materials into OPVs extends the absorption spectrum range,thereby enhancing the photon-harvesting ability of the devices,due to which they have been widely used for the construction of semitransparent solar cells with single-junction or tandem architectures.NIR photodiodes have tremendous potential in industrial,military,and scientific applications,such as remote control of smart electronic devices,chemical/biological sensing,environmental monitoring,optical communication,and so forth.These practical and potential applications have stimulated the development of NIR photoelectric materials,which in turn has given impetus to innovation in light-harvesting systems.In this review,we summarize the common molecular design strategies of NIR photoelectric materials and enumerate their applications in OPVs and OPDs.

Changing to Poly（rod-coil） Polymers： A Promising Way for an Optoelectronic Compound to Improve Its Film Formation

Good film formation is one of basic requirements for organic optoelectronic materials to achieve the capability for fabrication of large area devices. Small molecular optoelectronic compounds have a definite chemical structure and clear device performance, and thus are welcomed in the field. However, they are generally suffering from poor film formation, especially in a large area. For addressing it, this contribution proposes and demonstrates a strategy, that is, changing them into poly（rod-coil） polymers. With one optoelectronic compound [BDT（DTBT）2] and three poly（rod-coil） polymers （P1, P2, and P3） having different non-conjugated coil segments as examples, the work clearly shows that the change to poly（rod-coil） polymers keeps many basic optoelectronic properties of the refer- ence compound, including light absorption in solution, bandgap and frontier orbital energy levels, but suppresses strong intermolecular interactions and crystalline structure in film state. Further comparisons on film formation quality on glass and ITO glass illustrate that all the three polymers have a better film formation property than the reference compound.