Circularly polarized luminescence (CPL) materials with aggregation-induced emission (AIE) performance have attracted extensive attention. In this study, we successfully achieve CPL emissions in chiral helical substituted polyacetylenes with tetraphenylethene (TPE) pendants. The polymers are constructed by copolymerization of an achiral TPE-containing acetylenic monomer with a chiral monomer. The obtained polymer exhibits unique state-dependent CPL behavior. More specifically, the polymer is CPLsilent in a dispersion state but CPL-active in solid thin films with a high luminescence dissymmetry factor (|g lum | = 3.6 × 10 −2 ). Moreover, significantly different from the common chirality transfer mechanism for preparing CPLactive materials, the CPL generation herein is due to the "matching rule" between fluorescent moieties and chiral helical polyacetylene. The present study provides new perspectives for preparing CPL materials with large g lum values in the solid state.

parameter for judging the material performance, [30] in which the maximum |g lum | value is 2 when absolutely left-handed or right-handed CPL emission is generated. Nevertheless, the |g lum | values of most reported CPL-active materials are mainly located between 10 −5 and 10 −2 , which are far from our expectation and cannot satisfy the demands for future applications. On the other hand, it is well-acknowledged that multicolor emissions especially RGB colors are important in display technology. Therefore, in consideration of the demands in practical applications, constructing CPL-active materials with both color-tunable emissions and high g lum values is of great significance. In the previous study, we have reported that chiral polyacetylenes with helical structures are good candidates for constructing CPL-active materials with high g lum values up to 10 −1. [31] Subsequently, we found that chiral helical polyacetylenes could serve as handedness-selective fluorescence filters to powerfully transform unpolarized fluorescent light into CPL emission. [32] Following this strategy, full-color and white-color CPL-active materials were easily constructed by combining chiral helical polyacetylenes with achiral fluorescence dyes. [32,33] Based on the above investigations, the relationship between helical structures and light shows unique charm and deserves more attention. The importance of such direction is more clearly demonstrated when considering the widespread helical structures and circularly polarized light in nature and living organisms. [34-38] In this contribution, we report our success in fabricating color-tunable CPL emissions by taking helical polyacetylenes as fluorescence converters. When blue-color circularly polarized light passes through the helical polyacetylenes with different conjugated lengths, multicolor CPL emissions of cyan, green, and orange are obtained, with high g lum values in the range of 10 −2-10 −1. It should be pointed out that, in spite of some publications concerning multicolor CPL materials reported by our group and others, [32,33,39-42] the multicolor CPLs therein are mainly realized from various fluorescent substances with different emission wavelength. In the present study, however, color-tunable CPL emissions are conveniently achieved from a single fluorescence substance, merely by tuning the conjugated length of helical polyacetylenes with commercial organic solvents. In particular notably, neither any covalent nor noncovalent interaction is required during the CPL color-tuning process, demonstrating the universality and superiority of the strategy established in the present work. Circularly polarized luminescence (CPL) materials are currently drawing rapidly increasing interest. However, constructing color-tunable CPL materials is still a big challenge, primarily due to the lack of simple, powerful, and universal preparation strategies. In this contribution, color-tunable CPL emissions are easily realized by taking helical polyacetylenes as fluorescence converters. The investigat...

No abstract

III-nitrides are attracting considerable attention as promising materials for a wide variety of applications due to their wide coverage of direct bandgap range, high electron mobility, high thermal stability and many other exceptional properties. The lightemitting diodes based on III-nitrides revolutionize the solid-state lighting industry. III-nitrides based solar cells and thermoelectric generators support the sustainable energy progress, and the IIInitrides are better alternatives for power and radio frequency (RF) electronics compared with silicon. The doped III-nitrides' magnetic properties and sensitivity to radiation can contribute to novel spintronic and nuclear detection devices. This paper will review III-nitride material properties and their corresponding applications in LEDs, solar cells, power and radio frequency (RF) electronics, magnetic devices, thermoelectrics and nuclear detection. The typical values of electrical, optical, thermoelectric, magnetic properties are cited, the current state of art investigations are reported, and the future applications are estimated.

In this work, we clarify the underlying physics and the acceptor ionization process in the In-Mg co-doping GaN. The fundamental understandings are also applicable for other co-doping nitride systems. We show the effective acceptors ionization stems mainly from the band structure tuning effect of the 4d orbitals of In atoms. In addition, temperature dependent defect-related photoluminescence analysis was proposed to examine the energy position of Mg impurity levels, which is crucially important in the design for high p-doping. Finally, a hole concentration, which is nearly one order of magnitude higher than what is typically achievable by direct Mg-doping, was achieved.