CdTe/CdSe nanocrystal (NC) solar cells with an inverted structure (ITO/ZnO/CdSe/CdTe/Au) have been successfully fabricated by a simple solution process coupled with layer-by-layer sintering techniques. It was found that the device performance is strongly dependent on the annealing strategy, the thickness of the acceptor layer and on the buffer layer of ZnO when the optimal thickness of CdTe is adopted. Without the ZnO buffer layer, a thin film of the CdSeNCs on an ITO substrate shows a rougher morphology, resulting in device shunting. However, when a 40 nm-thick ZnO buffer layer and 60 nm-thick CdSe were employed, the device shows a much higher PCE of 5.81% under device conditions, post-annealing at 340 8C. This value is the highest efficiency ever reported to date for a CdTe/CdSe NC solar cell. Comparing with CdTe/CdSe NC solar cells with the normal device configuration, this device with an inverted structure simultaneously offers good Ohmic contact for carrier collection and efficient harvesting of solar photons in a wide wavelength.

With the rapid development of flexible electronic devices (especially flexible LCD/OLED), flexible transparent electrodes (FTEs) with high light transmittance, high electrical conductivity, and excellent stretchability have attracted extensive attention from researchers and businesses. FTEs serve as an important part of display devices (touch screen and display), energy storage devices (solar cells and super capacitors), and wearable medical devices (electronic skin). In this paper, we review the recent progress in the field of FTEs, with special emphasis on metal materials, carbon-based materials, conductive polymers (CPs), and composite materials, which are good alternatives to the traditional commercial transparent electrode (i.e., indium tin oxide, ITO). With respect to production methods, this article provides a detailed discussion on the performance differences and practical applications of different materials. Furthermore, major challenges and future developments of FTEs are also discussed.

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In this study, CdTe/CdSe NCs BNH solar cells with PCE of 6.25% were successfully fabricated in an inverted structure configuration ITO/ZnO/CdSe/CdSe:CdTe/CdTe/Au by a solution process.

Tungsten trioxide (WO3) is a wide band gap semiconductor material that is used as an important electrochromic layer in electrochromic devices. In this work, the effects of the annealing temperature on the optical band gap of sol-gel WO3 films were investigated. X-ray Diffraction (XRD) showed that WO3 films were amorphous after being annealed at 100 °C, 200 °C and 300 °C, respectively, but became crystallized at 400 °C and 500 °C. An atomic force microscope (AFM) showed that the crystalline WO3 films were rougher than the amorphous WO3 films (annealed at 200 °C and 300 °C). An ultraviolet spectrophotometer showed that the optical band gap of the WO3 films decreased from 3.62 eV to 3.30 eV with the increase in the annealing temperature. When the Li+ was injected into WO3 film in the electrochromic reaction, the optical band gap of the WO3 films decreased. The correlation between the optical band gap and the electrical properties of the WO3 films was found in the electrochromic test by analyzing the change in the response time and the current density. The decrease in the optical band gap demonstrates that the conductivity increases with the corresponding increase in the annealing temperature.

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In this work, we fabricated a high-mobility amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) based on alumina oxide (Al2O3) passivation layer (PVL) and copper (Cu) source/drain electrodes (S/D). The mechanism of the high mobility for a-IGZO TFT was proposed and experimentally demonstrated. The conductivity of the channel layer was significantly improved due to the formation of metallic In nanoparticles on the back channel during Al2O3 PVL sputtering. In addition, Ar atmosphere annealing induced the Schottky contact formation between the Cu S/D and the channel layer caused by Cu diffusion. In conjunction with high conductivity channel and Schottky contact, the a-IGZO TFT based on Cu S/D and Al2O3 PVL exhibited remarkable mobility of 33.5–220.1 cm2/Vs when channel length varies from 60 to 560 μm. This work presents a feasible way to implement high mobility and Cu electrodes in a-IGZO TFT, simultaneously.