Organic optoelectronic devices exhibit distinctive photoresponse to the near-infrared (NIR) light and show great potential in many fields. However, the optoelectronic properties of the existing devices hardly meet the technical requirements of new applications such as energy conversion and health sensing, thus raising the demand to develop high-performance NIR organic semiconductors. To address this issue, a new NIR material, namely, BFIC, is designed and synthesized by inserting fluorothieno­[3,4-b]­thiophene (FTT) as a π-bridge. Since the introduction of FTT can extend the conjugation, stabilize the quinoid resonant structure, and enhance the intramolecular charge transfer, BFIC displays a broad and intense absorption in the NIR region, ranging from 700 to 1050 nm. As a result, the organic solar cell based on BFIC and a polymer donor PTB7-Th realizes a power conversion efficiency of 10.38%. The semitransparent organic solar cell (OSC) shows a power conversion efficiency of 6.15%, accompanied by an average visible transmittance of 38.79% due to the selective photoresponse in the NIR range. The organic photodetector based on PTB7-Th:BFIC delivers a broad spectral response ranging from 330 to 1030 nm with a specific detectivity over 1013 Jones under the self-powered mode, which is one of the highest detectivities among the broad-band organic photodetectors.

Sn‐based perovskites are the most promising alternative materials for Pb‐based perovskites to address the toxicity problem of lead. However, the development of SnII‐based perovskites has been hindered by their extreme instability. Here, we synthesized efficient and stable lead‐free Cs4SnBr6 perovskite by using SnF2 as tin source instead of easily oxidized SnBr2. The SnF2 configures a fluorine‐rich environment, which can not only suppress the oxidation of Sn2+ in the synthesis, but also construct chemically stable Sn−F coordination to hinder the electron transfer from Sn2+ to oxygen within the long‐term operation process. The SnF2‐derived Cs4SnBr6 perovskite shows a high photoluminescence quantum yield of 62.8 %, and excellent stability against oxygen, moisture, and light radiation for 1200 h, representing one of the most stable lead‐free perovskites. The results pave a new pathway to enhance the optical properties and stability of lead‐free perovskite for high‐performance light emitters.

Abstract:Colloidal zinc oxide (ZnO) nanocrystals generated from the high temperature and nonaqueous approache are attractive for use in solution-processed electrical and optoelectronic devices. However, the asprepared colloidal ZnO nanocrystals by this approach are generally capped by ligands with long alkyl-chains, which is disadvantage for solution-processed devices due to hindering charge transport. Here we demonstrate an effective ligand exchange process for the colloidal ZnO nanocrystals from the high temperature and nonaqueous approach by using n-butylamine. The ligand exchange process was carefully characterized. The thin films based on colloidal ZnO nanocrystals after ligand exchange exhibited dramatically enhanced UV photoconductivity.

Organic photodiodes (OPDs) have shown great promise for potential applications in optical imaging, sensing, and communication due to their wide-range tunable photoelectrical properties, low-temperature facile processes, and excellent mechanical flexibility. Extensive research work has been carried out on exploring materials, device structures, physical mechanisms, and processing approaches to improve the performance of OPDs to the level of their inorganic counterparts. In addition, various system prototypes have been built based on the exhibited and attractive features of OPDs. It is vital to link the device optimal design and engineering to the system requirements and examine the existing deficiencies of OPDs towards practical applications, so this review starts from discussions on the required key performance metrics for different envisioned applications. Then the fundamentals of the OPD device structures and operation mechanisms are briefly introduced, and the latest development of OPDs for improving the key performance merits is reviewed. Finally, the trials of OPDs for various applications including wearable medical diagnostics, optical imagers, spectrometers, and light communications are reviewed, and both the promises and challenges are revealed. Graphical Abstract

A gate driver in array (GIA) design based on the amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor (TFT) is developed for narrow border displays. In the design, each TFT in the gate driver circuits is divided into a certain number of smaller size devices, which can be placed in different subpixels. Therefore, the pixel aperture ratio loss is minimized, and uniform placement of the gate driver circuits over the pixel array area is able to be achieved. The proposed step-like repeating block structure further reduces the occupied area of the signal interconnects. A 12.4-inch fringe field switching (FFS) liquid crystal display (LCD) panel of ultra-narrow border (0.5 mm) is demonstrated with reliable operation based on this GIA design, proving its potential for practical applications. Keywordsdisplay; narrow border; indium gallium zinc oxide; thin-film transistor; gate driver on array; gate driver in array