Responsivity

About: Responsivity is a research topic. Over the lifetime, 9918 publications have been published within this topic receiving 186118 citations.

Ultrasensitive and Fast All‐Inorganic Perovskite‐Based Photodetector via Fast Carrier Diffusion

Abstract: Low trap-state density, high carrier mobility, and efficient charge carrier collection are key parameters for photodetectors with high sensitivity and fast response time. This study demonstrates a simple solution growth method to prepare CsPbBr3 microcrystals (MCs) with low trap-state density. Time-dependent photoluminescence study with one-photon excitation (OPE) and two-photon excitation (TPE) indicates that CsPbBr3 MCs exhibit fast carrier diffusion with carrier mobility over 100 cm2 V-1 S-1 . Furthermore, CsPbBr3 MC-based photodetectors with high charge carriers' collection efficiency are fabricated. Such photodetectors show ultrahigh responsivity (R) up to 6 × 104 A W-1 with OPE and high R up to 6 A W-1 with TPE. The R for OPE is over one order of magnitude higher (the R for TPE is three orders of magnitude higher) than that of previously reported all-inorganic perovskite-based photodetectors. Moreover, the photodetectors exhibit fast response time of ≈1 ms, which corresponds to a gain ≈105 and a gain- bandwidth product of 108 Hz for OPE (a gain ≈103 and a gain-bandwidth product of 106 Hz for TPE).

Circularly polarized light detection using chiral hybrid perovskite.

Abstract: Circularly polarized light (CPL) detection is required in various fields such as drug screening, security surveillance and quantum optics. Conventionally, CPL photodetector needs the installation of optical elements, imposing difficulties for integrated and flexible devices. The established CPL detectors without optical elements rely on chiral organic semiconductor and metal metamaterials, but they suffer from extremely low responsivity. Organic-inorganic hybrid materials combine CPL-sensitive absorption induced by chiral organics and efficient charge transport of inorganic frameworks, providing an option for direct CPL detection. Here we report the CPL detector using chiral organic-inorganic hybrid perovskites, and obtain a device with responsivity of 797 mA W-1, detectivity of 7.1 × 1011 Jones, 3-dB frequency of 150 Hz and one-month stability, a competitive combined feature for circularly polarized light detection. Thanks to the solution processing, we further demonstrate flexible devices on polyethylene terephthalate substrate with comparable performance. Optics-free circularly-polarized light detection has suffered from extremely low responsivity. Here Chen et al. demonstrate chiral organic–inorganic hybrid perovskite based detectors to distinguish circularly-polarized light with high responsivity of 797 mA/W.

Hybrid Graphene–Perovskite Phototransistors with Ultrahigh Responsivity and Gain

Abstract: Graphene is an attractive optoelectronic material for light detection because of its broadband light absorption and fast response time. However, the relatively low absorption cross-section, fast recombination rate, and the absence of gain mechanism have limited the responsivity of pure graphene-based phototransistor to ≈10−2 A W−1. In this work, a photoconductive gain of ≈109 electrons per photon and a responsivity of ≈6.0 × 105 A W−1 are demonstrated in a hybrid photodetector that consists of monolayer graphene covered with a thin layer of dispersive organolead halide perovskite (CH3NH3PbBr2I) islands. The unprecedented performance is attributed to the effective charge transfer and photogating effect, which were evidenced by photoluminescence quenching, time-resolved photoluminescence decay, scanning near-field optical microscopy, and photocurrent mapping. Unlike previous report which used perovskite bulk thin film, the perovskite islands have low bulk recombination rate of photogenerated carriers. The device also shows broad photodetection spectral range from ultraviolet to visible (250–700 nm), affording new opportunities for scalable UV detectors and imaging sensors.

Self-powered diamond/β-Ga2O3 photodetectors for solar-blind imaging

Abstract: Self-powered solar-blind photodetectors based on diamond/β-Ga2O3 heterojunctions have been fabricated. Under zero bias, these photodetectors show a peak responsivity of 0.2 mA W−1, and a sharp cutoff wavelength of 270 nm. The UV/visible rejection ratio is more than two orders of magnitude, indicating that these photodetectors respond mainly to solar-blind irradiation. These photodetectors can exhibit repeatability and stability without any external power supply. High quality images have been obtained using such a self-powered photodetector as a sensing pixel of an imaging system, and this study is the first report on the solar-blind imaging of Ga2O3 based photodetectors.

High-responsivity mid-infrared graphene detectors with antenna-enhanced photocarrier generation and collection

Abstract: Graphene is an attractive photoconductive material for optical detection due to its broad absorption spectrum and ultrashort response time. However, it remains a great challenge to achieve high responsivity in graphene detectors because of graphene’s weak optical absorption (only 2.3% in the monolayer graphene sheet) and short photocarrier lifetime (<1 ps). Here we show that metallic antenna structures can be designed to simultaneously improve both light absorption and photocarrier collection in graphene detectors. The coupled antennas concentrate free space light into the nanoscale deep-subwavelength antenna gaps, where the graphene light interaction is greatly enhanced as a result of the ultrahigh electric field intensity inside the gap. Meanwhile, the metallic antennas are designed to serve as electrodes that collect the generated photocarriers very efficiently. We also elucidate the mechanism of photoconductive gain in the graphene detectors and demonstrate mid-infrared (mid-IR) antenna-assisted graph...