Organic photodetectors (OPDs) have attracted continuous attention due to their outstanding advantages, such as tunability of detecting wavelength, low-cost manufacturing, compatibility with lightweight and flexible devices, as well as ease of processing. Enormous efforts on performance improvement and application of OPDs have been devoted in the past decades. In this Review, recent advances in device architectures and operation mechanisms of phototransistor, photoconductor, and photodiode based OPDs are reviewed with a focus on the strategies aiming at performance improvement. The application of OPDs in spectrally selective detection, wearable devices, and integrated optoelectronics are also discussed. Furthermore, some future prospects on the research challenges and new opportunities of OPDs are covered.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/advs.202002418

Recent Progress in Organic Photodetectors and their Applications.

Ultrahigh Detectivity in Spatially Separated Hole/Electron Dual Traps Based Near-Infrared Organic Phototransistor

Colloidal quantum dots (CQDs) have attracted tremendous research interests for future generation energy, electronic, optoelectronic and bio-imaging applications due to their fascinating material properties, such as solution processability at room temperature and under ambient conditions, compatibility with various functional materials, and high photo-stability as well as photo-sensitivity. Among various optoelectronic applications of CQDs, in particular, optical light sensors which convert photonic energy into electrical signals have been of particular interests because they are one of the key building blocks for modern communication and imaging applications including medical X-ray and near-infrared imaging, visible light cameras, and machine vision. However, CQDs, which have been widely researched for photodetectors so far, contain toxic and hazardous heavy metals, namely, lead (Pb), cadmium (Cd), and mercury (Hg). These substances are extremely toxic and harmful to the environment as well as human beings. Therefore, it is highly desirable to substitute CQDs containing the heavy metals with non-toxic and environmentally friendly ones to realize green optoelectronics. In this review article, we introduce various kinds of heavy metal free CQDs and their applications to photodetectors. The article comprehensively includes working mechanisms of the photodetector, various kinds of non-toxic and environmentally friendly CQDs-based photodetectors, advanced heterojunction photodetectors, and discussion for future perspectives.

/pdf/toward-green-optoelectronics-environmental-friendly-3b9123qe26.pdf

Toward Green Optoelectronics: Environmental-Friendly Colloidal Quantum Dots Photodetectors

High-Performance Organic Photodiodes for Blue-Light Hazard Detection

High-Performance organic photodiodes for Blue-Light hazard detection

Organic phototransistors (OPTs) simultaneously introduce photo-induced holes and electrons into the structure of organic field-effect transistors (OFETs). The memory effect of the minority carrier is the origin of the large dark current and slow response during the light on/off switching, which is detrimental to the OPT performance and cycling stability. In this research, we report a novel OPT working mode by photoelectric dual control. After each light switch, the dark current is erased by the gate voltage in depletion mode which remains unchanged during light off; the photocurrent increases by device converting to accumulation mode when the light is on. In this way, high performance OPTs have been obtained in an FBT-Th4(1,4) : PC61BM (5 : 1) composite film with the structure of Si/SiO2/OTS/FBT-Th4(1,4) : PC61BM/Au electrodes, which shows a broad spectral response (maximum values at zero gate bias: R 1.2 × 105 A W−1, gain 3.7 × 105 and D* 3.18 × 1016 Jones) from 410 to 740 nm (calculated from the transfer curve). The best performance with photoelectric dual control under 0.0031 mW cm−2@405 nm is achieved with an on/off current ratio of 1.0 × 106, response 1.6 × 104 A W−1, gain 5.0 × 104, spectral detectivity 2.3 × 1017 Jones and response time sub-40 ms, which makes the phototransistor a very promising component for light sensing applications.

Ultrahigh photosensitive organic phototransistors by photoelectric dual control

Energy level gradient trapping based on different work functions of ZnO enhancing response and stablity for lateral photodetectors

Phase Control Behavior of Lateral Polymer Photodetectors Using Strong Aggregation Bulk Heterojunction Film

Based on the first principle pseudopotential plane wave method, the electronic structure of zinc-blende semiconductor GaN is calculated. Using the relativistic treatment of valence states, the spin orbit splitting energy of valence band top near the center of Brillouin region is calculated. Based on the effective mass approximation theory, the effective mass of electrons near the bottom of the conduction band and the effective mass of light and heavy holes near the Γ point along the directions of [100], [110] and [111] are calculated. These parameters are valuable and important parameters of optoelectronic materials.

/pdf/first-principles-calculation-of-electronic-properties-and-2qc4bcbn.pdf

Huanyou Wang

Papers

Ultrahigh photosensitive organic phototransistors by photoelectric dual control

Energy level gradient trapping based on different work functions of ZnO enhancing response and stablity for lateral photodetectors

Phase Control Behavior of Lateral Polymer Photodetectors Using Strong Aggregation Bulk Heterojunction Film

First principles calculation of electronic properties and effective mass of zinc-blende GaN