A 'turn-on' fluorescent colorimetric device for Hg(2+) sensing was built using a dual light-emitting diode system. Fluorescence generated from a rhodamine derivative (RHD), an indicator for Hg(2+) sensing, was combined with a background red light, and the complex light was captured by a commercial charge coupled device camera or by the naked eye.

Despite the widespread use of solution-processable hybrid organic-inorganic perovskites in photovoltaic and light-emitting applications, determination of their intrinsic charge transport parameters has been elusive due to the variability of film preparation and history-dependent device performance. Here we show that screening effects associated to ionic transport can be effectively eliminated b...

A high ambient contrast ratio display device using a transparent organic light emitting diode (OLED) or transparent quantum-dot light-emitting diode (QLED) with embedded multilayered structure and absorber is proposed and its performance is simulated. With the help of multilayered structure, the device structure allows almost all ambient light to get through the display device and be absorbed b...

We performed depth-resolved PL and Raman spectral mappings of a GaN-based LED structure grown on a patterned sapphire substrate (PSS). Our results showed that the Raman mapping in the PSS-GaN heterointerface and the PL mapping in the InxGa1-xN/GaN MQWs active layer are spatially correlated. Based on the 3D construction of E2(high) Raman peak intensity and frequency shift, V-shaped pits in the M...

Semiconductor nanowires are nanoscale structures holding promise in many fields such as optoelectronics, quantum computing, and thermoelectrics. Nanowires are usually grown vertically on (111)-oriented substrates, while (100) is the standard in semiconductor technology. The ability to grow and to control impurity doping of ⟨100⟩ nanowires is crucial for integration. Here, we discuss doping of s...

Organic light emitting diodes have undergone rapid advancement over the course of the past decade. Similarly, quantum dot synthesis has progressed to the point that room temperature highly efficient photoluminescence can be realized. It is the purpose of this work to utilize the beneficial properties of these two material sets in a robust light emitting device. New deposition techniques are nec...

Low-temperature electroluminescence from ZnO nanowire light-emitting arrays is reported. By inserting a thin MgO current blocking layer in between ZnO nanowire and p-GaN, high-purity UV light emission at wavelength 398 nm was obtained. As the temperature is decreased, contrary to the typical GaN-based light emitting diodes, our device shows a decrease of optical output intensity. The results ar...

Polymer White-light-emitting devices WPLEDs with single layer structures are fabricated by the spincoating method. The device structure used here is indium-tin-oxide(ITO)/polyethylene dioxythiophene(PEDOT:PSS)/polymer blend/Ca/Al, whose blend consists poly N-vinylcarbazole(PVK) hole transporting host polymer, an electron transporting materials 2-4-biphenylyl-5-tert-butylphenyl1,3,4-oxadiazole(P...

We have developed highly efficient white top-emitting organic light-emitting devices (TOLEDs) with broad emission by modifying both anode and cathode. To alleviate the undesirable microcavity effect and obtain “broad” white emission, CFxcoated Ag anode with modified reflectivity and an index-matching layer (SnO2) capped on thin Ca/Ag cathode with a maximal transparency of 80% were employed. A t...

A new type of bottom-emission electroluminescent device is described in which a metal oxide is used as the electron-injecting contact. The preparation of such a device is simple. It consists of the deposition of a thin layer of a metal oxide on top of an indium tin oxide covered glass substrate, followed by the solution processing of the light-emitting layer and subsequently the deposition of a...