Highly ordered CdS nanostructure arrays were successfully fabricated via a simple two-step metal-organic chemical vapor deposition process. Both stimulated emission and field-emission measurements were carried out in an attempt to understand the correlation between the morphologies, alignments, and emission performances of five ordered CdS nanostructure array types (well-aligned truncated nanocones, nanorods, cleft nanorods, quasi-aligned nanowires, and nanowires). The 1D CdS nanostructures of various types displayed notable differences in stimulated and field-emission performances. The stimulated emission strongly correlated with the structure alignment: the better the alignment, the lower the threshold. Both of the alignments and aspect ratios greatly affected the field-emission properties; the CdS emitters of higher aspect ratio and better alignment exhibited better field-emission performance. Thus the well-aligned CdS nanorod arrays had the lower threshold for stimulated emission, and quasi-aligned nanowire arrays produced the higher field-emission current and possessed the lower turn-on fields.

Morphology-dependent stimulated emission and field emission of ordered CdS nanostructure arrays

Electrochromic devices (ECDs) have been regarded as promising candidates for energy-saving smart windows, next-generation displays and wearable electronics due to their significant benefits of simple and adjustable structures, low power consumption, flexible and stretchable features, and eye-friendly modes for displays. However, there are many existing issues waiting to be solved such as durability, reversibility and inadequate switching performances. These insurmountable technical bottlenecks significantly slow down the commercialization of next-generation ECDs. Nanomaterials with superior active reaction surface area have played indispensable roles in optimizing heterogeneous electron transfer and homogeneous ion transfer for ECDs and other optoelectronic devices. In recent years, with the joint efforts of various outstanding research teams, new kinds and methods for nanomaterials to fabricate ECDs with excellent performances have been rapidly developing. This review highlights the latest exciting results regarding the design and application of new and unique nanomaterials for each layer of ECDs. Meanwhile, the structures, mechanisms, features and preparation of the reported nanomaterials to improve the electrochromic properties have been discussed in detail. In addition, the remaining challenges and corresponding strategies of this field are also proposed. Hopefully, this review can inspire more and more researchers to enrich the nanomaterials for ECDs and other related fields to overcome faced technical barriers by innovative means and promote industrialization of ECDs and other optoelectronic technologies.

Advances in nanomaterials for electrochromic devices

Eco-friendly geopolymer prepared from solid wastes: A critical review.

Flexible Transparent Supercapacitors: Materials and Devices

The red shift and the broadening of the Raman signal from microcrystalline silicon films is described in terms of a relaxation in the q-vector selection rule for the excitation of the Raman active optical phonons. The relationship between width and shift calculated from the known dispersion relation in c-Si is in good agreement with available data. An increase in the decay rate of the optical phonons predicted on the basis of the same model is confirmed experimentally.

The one phonon raman spectrum in microcrystalline silicon

A fast and flexible all-organic electrochromic device, fabricated using polythiophene and PCBM as active materials and plastic substrate, which shows very good power efficiency as well, has been re...

https://pubs.acs.org/doi/pdf/10.1021/acsaelm.8b00012

Polythiophene–PCBM-Based All-Organic ElectrochromicDevice: Fast and Flexible

A power-efficient, ultrafast and stable organic–inorganic hybrid electrochromic device fabricated using WO3 and P3HT as active materials has been demonstrated herein for dual application in an electrochromic window as well as an IR filter. The device when turned ON using a bias as low as 1 V shows heat shielding effect as well as increased optical transparency to keep the area cooler by ∼8 °C (22%) to maintain the room temperature at 302 K, as imaged using an IR camera. The solid state electrochromic IR filter device was fabricated in simple cross bar geometry with the WO3/P3HT bilayer sandwiched between two electrodes. The device works on the principle of a bias-induced redox change process, as established using electrochemical and spectroscopic investigations. The device exhibits superior electrochromic behavior with dual function, with a maximum color contrast of ∼60% in the IR region with excellent coloration efficiency of ∼380 cm2 C−1 at 520 nm and stability of more than 1600 ON/OFF cycles without compromising its performance. Possibility of the device to be used as an electrochromic window and heat shield has been demonstrated using real life experiments.

Polythiophene-nanoWO3 bilayer as an electrochromic infrared filter: a transparent heat shield

An “all-inorganic”, fast, and power-efficient solid-state electrochromic device has been realized by choosing Co3O4 and PB films as complementing electrodes. The prussian blue and cobalt oxide film...

Prussian Blue-Cobalt Oxide Double Layer for Efficient All-Inorganic Multicolor Electrochromic Device

Polythiophene -viologen bilayer for electro-trichromic device

Electrochromic performance of an inorganic–organic layered blend consisting of prussian blue and ethyl viologen has been studied in the form of a device designed to test its performance as well as identify the working mechanism. Initially the sky-blue colored device, consisting of prussian blue and ethyl viologen electrodes, switches reversibly between transparent and dark blue states on application of electrical bias of up to 1.5 V with appropriate polarity. Raman spectroscopic and electrochemical investigations along with control experiments very clearly suggest that reversible redox switching of the two species are responsible for the electrochromism in the device. The fabricated device shows a good optical modulation of more than 50% in dual wavelength region of 400 and 600 nm (blue and red), serving as dual wavelength filter, while maintaining its optical durability for more than 8400 s (1400 pulses) with high coloration efficiency. The inorganic–organic hybrid device comprised of prussian blue and e...

Devesh K. Pathak

Papers

Polythiophene–PCBM-Based All-Organic ElectrochromicDevice: Fast and Flexible

Polythiophene-nanoWO3 bilayer as an electrochromic infrared filter: a transparent heat shield

Prussian Blue-Cobalt Oxide Double Layer for Efficient All-Inorganic Multicolor Electrochromic Device

Polythiophene -viologen bilayer for electro-trichromic device

Prussian Blue-Viologen Inorganic–Organic Hybrid Blend for Improved Electrochromic Performance