Surface passivation engineering for stable optoelectronic devices via hydroxyl-free ZnMgO nanoparticles.

ZnMgO nanoparticles (ZMO NPs) are widely used as electron transport layers in optoelectronic devices such as light-emitting diodes (LEDs) and photodiodes (PDs) primarily because of their facile synthesis and excellent electron transport properties. However, the surface hydroxyl groups (‒OH) on the ZMO NPs introduce charge traps, inhibit electron transport, and reduce device stability, particularly under ambient humidity and oxygen. Therefore, in this study, an alcohol treatment (AT) method was developed to remove surface ‒OH via proton transfer to effectively reduce trap states and dipole moments and enhance surface passivation.

Ultrathin, High-Aspect-Ratio Bismuth Sulfohalide Nanowire Bundles for Solution-Processed Flexible Photodetectors.

In this study, a novel synthesis of ultrathin, highly uniform colloidal bismuth sulfohalide (BiSX where X = Cl, Br, I) nanowires (NWs) and NW bundles (NBs) for room-temperature and solution-processed flexible photodetectors are presented. High-aspect-ratio bismuth sulfobromide (BiSBr) NWs are synthesized via a heat-up method using bismuth bromide and elemental S as precursors and 1-dodecanethiol as a solvent. Bundling of the BiSBr NWs occurs upon the addition of 1-octadecene as a co-solvent.

An ultra-sensitive colloidal quantum dot infrared photodiode exceeding 100 000% external quantum efficiency photomultiplication.

In this study, we present ultrasensitive infrared photodiodes based on PbS colloidal quantum dots (CQDs) using a double photomultiplication strategy that utilizes the accumulation of both electron and hole carriers. While electron accumulation was induced by ZnO trap states that were created by treatment in a humid atmosphere, hole accumulation was achieved using a long-chain ligand that increased the barrier to hole collection. Interestingly, we obtained the highest responsivity in photo-multiplicative devices with the long ligands, which contradicts the conventional belief that shorter ligands are more effective for optoelectronic devices.

Smart building block with colored radiative cooling devices and quantum dot light emitting diodes.

In this study, we design a smart building block with quantum-dot light-emitting diode (QLED) and colored radiative cooling devices. A smart light-emitting building block is fabricated using a bottom-inverted QLED that emits green light, an insulating layer, and a top radiative cooling structure that emits mid-infrared light. The heat generated during QLED operation is measured and analyzed to investigate the correlation between heat and QLED degradation.

Ultrasensitive Near-Infrared InAs Colloidal Quantum Dot-ZnON Hybrid Phototransistor Based on a Gradated Band Structure.

Amorphous metal oxide semiconductor phototransistors (MOTPs) integrated with colloidal quantum dots (QDs) (QD-MOTPs) are promising infrared photodetectors owing to their high photoconductive gain, low off-current level, and high compatibility with pixel circuits. However, to date, the poor mobility of conventional MOTPs, such as indium gallium zinc oxide (IGZO), and the toxicity of lead (Pb)-based QDs, such as lead sulfide and lead selenide, has limited the commercial applications of QD-MOTPs. Herein, an ultrasensitive QD-MOTP fabricated by integrating a high-mobility zinc oxynitride (ZnON)-based MOTP and lead-free indium arsenide (InAs) QDs is demonstrated.

Highly efficient white electroluminescent devices with hybrid double emitting layers of quantum dots and phosphorescent molecules.

Hybrid quantum dot light-emitting diodes (QLEDs) with double emitting layers (EMLs) were developed to achieve highly efficient white emission. The first emitting layer comprised blue and green quantum dots that were deposited by spin-coating, and the second emitting layer comprised red phosphorescent organic molecules that were deposited by thermal evaporation without any buffer layer. These unique trichromatic devices showed three distinct electroluminescent (EL) peaks with similar intensities at 15 V and the variation of the EL spectra with applied voltage was investigated systematically.