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This study demonstrates a broadband-tunable photonic bandgap (PBG) and thermally convertible laser with an ultra-low lasing threshold based on a gradient-pitched cholesteric liquid crystal (CLC) polymer template. The lowest energy threshold of the laser is 16 nJ per pulse under a pumped diameter of ca. 250 μm (i.e., 0.33 μJ per pulse per mm2), a value that is superior to those of other band-edge lasers based on most dye/quantum-dot-doped CLC systems. Owing to its multiple advantages, such as high stability, ultra-low lasing threshold, wide-band and linear spatial PBG-tunability, and lasing-mode convertibility, the CLC template device can be potentially used for photonics and display applications.

This study applies a low-cost solvothermal method to synthesize all-inorganic (lead-free cesium tin halide) perovskite quantum dots (AIPQDs) and to fabricate AIPQD-doped lasers with cholesteric liquid crystal (CLC) lasing cavities. The lasers present highly qualified lasing features of low threshold (150 nJ/pulse) and narrow line width (0.20 nm) that are attributed to the conjunction of the suppression of photoluminescence (PL) loss caused by the quantum confinement of AIPQDs and the amplification of PL caused by the band-edge effect of the CLC-distributed feedback resonator. In addition, the lasers possess highly flexible lasing-wavelength tuning features and a long-term stability under storage at room temperature and under high humidity given the protective role of CLC. These advantages are difficult to confer to typical light-emitting perovskite devices. Given these merits, the AIPQD-doped CLC laser device has considerable potential applications in optoelectronic and photonic devices, including lighting, displays, and lasers.

This investigation is the first report of an optically stable and tunable laser using a quantum-dot (QD) embedded cholesteric liquid crystal (QD-CLC) microresonator with an added chiral-azobenzene moiety. The QD nanocrystal, CLC, and chiral-azobenzene play key roles in the highly stable fluorescence nano-emitter, microresonator, and photo-tuner in the photonic bandgap (PBG) of the CLC and associated lasing output, respectively. Experimental results show that both the PBG and lasing emission of the QD-CLC composite sample can be reversibly tuned under successive irradiation with UV and blue beams. The all-optical tunability of the laser is attributed to the successive elongation and shrinkage of the CLC pitch induced by UV- and blue beam-irradiation induced trans–cis and cis–trans back isomerizations of chiral-azobenzene, respectively. In addition, this composite laser has a high damage threshold (>85 μJ per pulse), and thus shows a uniquely high optical stability. This work has successfully opened up an opportunity for developing QD coherent light sources or lasers with good optical stability and tunability (e.g., optically stable and tunable single photon lasers).

A copolymer has been used as a template for enhanced optical properties of core–shell CdS/ZnSe quantum dots doped cholesteric liquid crystal. The lasing behavior is achieved at relatively low laser excitation energy threshold at room temperature. Low-threshold value and high-optical stability make this optical system promising for visible laser emitter applications.

Stannites are important contenders among thin-film solar cells due to their direct band gap and higher absorption coefficient. I 2 –II–IV–VI 4 nanocrystals of Cu 2 ZnSnSe 4 are stannite material with a near-optimum band gap of ∼1.5 eV. Semiconductor Cu 2 ZnSnSe 4 nanorods were successfully prepared via a relatively simple and convenient solvothermal route. The device parameters for a single junction Cu 2 ZnSnSe 4 solar cell under AM1.5G are as follows: open circuit voltage of 308 mV, short-circuit current of 29.9 mA/cm 2 , fill factor of 27%, and a power conversion efficiency of 2.48%. Based on a series of comparative experiments under various reaction conditions, the probable formation mechanism of crystals Cu 2 ZnSnSe 4 nanorods is proposed.

Kesterites are important contenders among thin-film solar cells due to their direct band gap and higher absorption coefficient. I 2 –II–IV–VI 4 nanocrystal of Cu 2 ZnSnS 4 is a chalcopyrite material with a near-optimum band gap of ∼1.5 eV. Semiconductor Cu 2 ZnSnS 4 nanorods were successfully prepared via a relatively simple and convenient solvothermal route. The device parameters for a single junction Cu 2 ZnSnS 4 solar cell under AM1.5G are as follows: open circuit voltage of 319 mV, short-circuit current of 25.5 mA/cm 2 , fill factor of 25, and a power conversion efficiency of 2.03%. Based on a series of comparative experiments under various reaction conditions, the probable formation mechanism of crystals Cu 2 ZnSnS 4 nanorods is proposed.

Herein, the fabrication of a lead-free cesium tin halide perovskite produced via a simple solvothermal process is reported for the first time. The resulting CsSnX3 (X = Cl, Br, and I) quantum rods show composition-tunable photoluminescence (PL) emissions over the entire visible spectral window (from 625 to 709 nm), as well as significant tunability of the optical properties. In this study, we demonstrate that through hybrid materials (CsSnX3) with different halides, the system can be tunable in terms of PL. By replacing the halide of the CsSnX3 quantum rods, a power conversion efficiency of 12.96% under AM 1.5 G has been achieved. This lead-free quantum rod replacement has demonstrated to be an effective method to create an absorber layer that increases light harvesting and charge collection for photovoltaic applications in its perovskite phase.

We have successfully prepared PVP/LiCoO2 nanofibers using an electrospinning route. These fibers were composed of very small crystalline grains uniformly linked with an average size. After annealing of the above precursor fibers at 700°C for 12 h, LiCoO2 nanofibers with 95 nm in diameter were composed of crystalline nanoparticles were successfully obtained. The morphology, crystal structure, and particle size of fibers has been characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD). The viscosities of solutions were measured with a LVDV Brookfield viscometer. Experimental results showed that the LiCoO2 with good crystalline and uniform diameter were obtained. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The preparation of crystalline silica nanorods is presented. Crystalline silica nanorods were synthesized via a simple solvothermal route using polyvinylbutyral (PVB) as a template in an autoclave with ethylenediamine as a solvent at 180 °C for 25 h. Silica nanorods with diameters in the range of 50–80 nm were obtained. The solvothermal route with a PVB template played affected the crystallization process and the growth of the silica nanorods. The as-synthesized products were characterized using X-ray diffraction, energy dispersive spectrometry, scanning electron microscopy, and transmission electron microscopy.

This study demonstrates for the first time a continuously tunable photonic bandgap (PBG) of wide spectral range based on a blue phase (BP) wedge cell. A continuously shifting PBG of the BP wedge cell occurs due to the thickness gradient of the wedge cell at a fixed temperature. The wedge cell provides a gradient of boundary force on the LCs and thus forms a distribution of BP crystal structure with a gradient lattice. Additionally, a spatially tunable lasing emission based on a dye-doped BP (DDBP) wedge cell is also demonstrated. The tunable band of the PBG and lasing emission is about 130 nm and 70 nm, respectively, which tuning spectral ranges are significantly wider than those of CLC and DDCLC wedge cells, respectively. Such a BP device has a significant potential in applications of tunable photonic devices and displays.

Cadmium Tellurium (CdTe) nanorods were successfully synthesized by a novel soft-chemical solvothermal method with ethylenediamine template. The ethylenediamine plays a critical role in the formation of CdTe nanocrystals. Single-crystalline CdTe with rod-like and flower-like morphologies has been successfully synthesized at 120 °C for 4 h. The prepared nanorods have cubic characteristics with a diameter of about 60 nm and a length of up to several micrometers. The nanorod exhibits a concentration tunable photoluminescence and a narrow full width at half-maximum (FWHM) value of PL spectra can be obtained, which may be useful for developing solar cell devices or LED, chemical sensors or in optical device. Based on a series of comparative experiments under different reaction conditions, the probable formation mechanism and photoluminescence emission of CdTe nanocrystals are proposed.

Chalcopyrite quaternary semiconductor Cu(In(x)B(1-x))Se(2) nanocrystals have been successfully prepared via a relatively simple and convenient solvothermal route. The effect of different solvents on the formation of the product also indicates that diethylenetriamine is the optimal solvent for this reaction. The device parameters for a single junction Cu(In(x)B(1-x))Se(2) solar cell under AM1.5G are as follows: an open circuit voltage of 265 mV, a short-circuit current of 25.90 mA/cm(2), a fill factor of 34%, and a power conversion efficiency of 2.34%. Based on a series of comparative experiments under different reaction conditions, the probable formation mechanism of crystal Cu(In(x)B(1-x))Se(2) nanorods is proposed.

Correction for ‘Surface passivation assisted lasing emission in the quantum dots doped cholesteric liquid crystal resonating cavity with polymer template’ by Lin-Jer Chen et al., RSC Adv., 2014, 4, 52804–52807.

Chalcopyrites are important contenders among thin-film solar cells due to their direct band gap and higher absorption coefficient. Copper–boron–selenium (CuBSe2) is a chalcopyrite material with a near-optimum band gap of ∼3.13 eV. Semiconductor CuBSe2 nanorods were successfully prepared via a relatively simple and convenient solvothermal route. The device parameters for a single junction CuBSe2 solar cell under AM 1.5 G are as follows: open circuit voltage of 310 mV, short-circuit current of 25.5 mA cm−2, fill factor of 24%, and a power conversion efficiency of 1.89%. Based on a series of comparative experiments under various reaction conditions, the probable formation mechanism of crystals CuBSe2 nanorods is proposed.