Lead sulfide (PbS) quantum dots (QDs) have great potential in optoelectronic applications because of their desirable characteristics as a light absorber for near-infrared (NIR) photodetection. However, most PbS-based NIR photodetectors are two-terminal devices, which require an integrated pixel circuit to be practical photosensors. Here we report on PbS QD/indium gallium zinc oxide (InGaZnO, IGZO) metal oxide semiconductor hybrid phototransistors with a photodetection capability between 700 and 1400 nm, a range that neither conventional Si nor InGaAs photodetectors can cover. The new hybrid phototransistor exhibits excellent photoresponsivity of over 10⁶ A W⁻¹ and a specific detectivity in the order of 10¹³ Jones for NIR (1000 nm) light. Furthermore, we demonstrate an NIR (1300 nm) imager using photogating inverter pixels based on PbS/IGZO phototransistors at an imaging frequency of 1 Hz with a high output voltage photogain of ~4.9 V (~99%). To the best of our knowledge, this report demonstrates the first QD/metal oxide hybrid phototransistor-based flat panel NIR imager. Our hybrid approach using QD/metal oxide paves the way for the development of gate-tunable and highly sensitive flat panel NIR sensors/imagers that can be easily integrated.

Colloidal quantum dots (QDs) are an emerging class of new materials due to their unique physical properties. In particular, colloidal QD based light emitting diodes (QDLEDs) have been extensively studied and developed for the next generation displays and solid-state lighting. Among a number of approaches to improve performance of the QDLEDs, the most practical one is optimization of charge transport and charge balance in the recombination region. Here, we suggest a polyethylenimine ethoxylated (PEIE) modified ZnO nanoparticles (NPs) as electron injection and transport layer for inverted structure red CdSe-ZnS based QDLED. The PEIE surface modifier, incorporated on the top of the ZnO NPs film, facilitates the enhancement of both electron injection into the CdSe-ZnS QD emissive layer by lowering the workfunction of ZnO from 3.58 eV to 2.87 eV and charge balance on the QD emitter. As a result, this device exhibits a low turn-on voltage of 2.0–2.5 V and has maximum luminance and current efficiency values of 8600 cd/m² and current efficiency of 1.53 cd/A, respectively. The same scheme with ZnO NPs/PEIE layer has also been used to successfully fabricate green, blue and white QDLEDs.

With the rapid development of wearable electronic devices, multifunctional ultrarobust, thermoconductive, nonflammable, and electromagnetic interference (EMI) shielding films which are widely utilized to efficiently dissipate heat generated from electronic components are in high demand. The poor scalability and mechanical flexibility of multifunctional papers usually hinder their practical application. In this study, mass-scalable ultrarobust graphene nanoplatelet (GnP) cross-linked aramid nanofiber (ANF) papers with a nacre-bioinspired structure are fabricated via an evaporation-induced self-assembly approach. By chemical cross-linking between two-dimensional GnPs and one-dimensional ANFs in the nacre-bioinspired structure by a phosphorus agent, the excellent toughness and folding endurance of the GnP based ANF papers have been successfully achieved with simultaneous integration of high-level multifunctional properties. Specifically, the ultrarobust GnP based ANF paper with 50 wt% GnP loading exhibits exceptional ultimate tensile strength (437 MPa), Young's modulus (19.7 GPa) and toughness (23.9 MJ m⁻³) as well as superb folding endurance after 10 000 bending cycles. Moreover, the highly ordered alignment of GnP induced an unprecedented thermal/electrical conductivity, and the GnP (50 wt%) based ANF papers with an ultrathin thickness of 21 μm show a superb in-plane thermal conductivity (up to 68.2 W m⁻¹ K⁻¹) and outstanding absolute effectiveness EMI shielding (up to 11 060 dB cm² g⁻¹) and are comparable with some commercial metals/alloys. These outstanding mechanical flexibility integrated superb thermal/EMI properties along with mass-scale production pave the way for practical applications of GnP based ANF papers in the development of advanced thermal management materials in autonomous cars, air vehicles and wearable devices.