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Laser-Induced Optoelectronic and Crystallographic Tuning of Methyl Ammonium Iodobismuthate Perovskite for Improved Performance of Sandwiched a?? Type Photodetectors
摘要： Towards development of high-performance perovskite based photodetectors, it is required that optical and crystallographic properties of perovskites materials be enhanced through perovskites materials modification. Many attempts on this quest result in alteration of chemical structure of perovskites materials through introduction of dopants. Here in, we present a clean and structural preservative technique of tuning optical and crystallographic properties of bismuth based lead free perovskite materials through irradiation with 2.5 mJ laser pulses ejected from Nd:YAG LASER operating in its second harmonics. XRD spectra show improved crystallinity and reduced crystallite size, SEM images show defect – minimized surface morphology, PL spectra show minimized rate of Auger recombination and absorbance spectra show improved absorbance at a constant band gap value. Consequently, simplified sandwiched architectural type photodetectors fabricated with the modified bismuth based perovskite materials display maximum photodetectivity of 4.5 × 109 Jones, maximum photoresponsivity of 25 μA/W, maximum photosensitivity of about 104 and minimum optical switching times of 10 ms under testing conditions of -2 V bias voltage, 15 mW/cm2 incident solar light and room temperature. Thus, laser pulses irradiation presents an alternative method of enhancing optical and crystallographic properties of perovskite materials from which highly efficient classes of photonics and photovoltaic devices can be developed.
关键词： Laser Irradiation,crystallographic properties,optical properties,perovskite photodetectors,lead free perovskites materials
更新于2025-09-23 15:21:01
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An Electrically Modulated Singlea??Color/Duala??Color Imaging Photodetector
摘要： An electrically modulated single-/dual-color imaging photodetector with fast response speed is developed based on a small molecule (COi8DFIC)/perovskite (CH3NH3PbBr3) hybrid film. Owing to the type-I heterojunction, the device can facilely transform dual-color images to single-color images by applying a small bias voltage. The photodetector exhibits two distinct cut-off wavelengths at ≈544 nm (visible region) and ≈920 nm (near-infrared region), respectively, without any power supply. Its two peak responsivities are 0.16 A W?1 at ≈525 nm and 0.041 A W?1 at ≈860 nm with a fast response speed (≈102 ns). Under 0.6 V bias, the photodetector can operate in a single-color mode with a peak responsivity of 0.09 A W?1 at ≈475 nm, showing a fast response speed (≈102 ns). A physical model based on band energy theory is developed to illustrate the origin of the tunable single-/dual-color photodetection. This work will stimulate new approaches for developing solution-processed multifunctional photodetectors for imaging photodetection in complex circumstances.
关键词： organic/perovskite photodetectors,response speed,dual-color imaging
更新于2025-09-23 15:21:01
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Boosting Perovskite Photodetector Performance in NIR Using Plasmonic Bowtie Nanoantenna Arrays
摘要： Triple-cation mixed metal halide perovskites are important optoelectronic materials due to their high photon to electron conversion efficiency, low exciton binding energy, and good thermal stability. However, the perovskites have low photon to electron conversion efficiency in near-infrared (NIR) due to their weak intrinsic absorption at longer wavelength, especially near the band edge and over the bandgap wavelength. A plasmonic functionalized perovskite photodetector (PD) is designed and fabricated in this study, in which the perovskite ((Cs0.06FA0.79MA0.15)Pb(I0.85Br0.15)3) active materials are spin-coated on the surface of Au bowtie nanoantenna (BNA) arrays substrate. Under 785 nm laser illumination, near the bandedge of perovskite, the fabricated BNA-based plasmonic PD exhibits ≈2962% enhancement in the photoresponse over the Si/SiO2-based normal PD. Moreover, the detectivity of the plasmonic PD has a value of 1.5 × 1012 with external quantum efficiency as high as 188.8%, more than 30 times over the normal PD. The strong boosting in the plasmonic PD performance is attributed to the enhanced electric field around BNA arrays through the coupling of localized surface plasmon resonance. The demonstrated BNA-perovskite design can also be used to enhance performance of other optoelectronic devices, and the concept can be extended to other spectral regions with different active materials.
关键词： near infrared,bowtie nanoantenna arrays,perovskite photodetectors,localized surface plasmon resonance
更新于2025-09-23 15:21:01
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Understanding the mechanisms of a conjugated polymer electrolyte for interfacial modification in solution-processed organic-inorganic hybrid perovskite photodetectors
摘要： Interfacial modification is an effective strategy to suppress the dark current in photodetectors for performance improvements. Here, solution-processed conjugated polymer electrolyte poly[(9,9-bis(3’-(N,N-dimethylamino) propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)](PFN), widely used for interface engineering in organic and perovskite solar cells, is introduced to the photovoltaic photodetectors based on α-phase formamidinium lead iodide (α-FAPbI3) perovskite at cathode interfaces. The PFN layer has both positive and negative impacts on the overall device performances. The steady-state device parameters including external quantum efficiency, photoresponsivity, and detectivity are enhanced because the dark current is effectively suppressed due to the hindered hole injection by the PFN layer. However, the incorporation of PFN leads to different transient photocurrent dynamics with a peak after turn-on and a long-lived tail after turn-off, increasing the fall time, although it has little impact on the rise time. The proposed mechanisms involve the trapping and detrapping effects of accumulated photogenerated electrons at the electron-transporting layer/PFN interface, which are proved by capacitance-voltage measurements and impedance spectroscopy analysis. Our results have important significance for understanding the different effects and mechanisms of conjugated polymer electrolytes for interfacial engineering in photodetectors and solar cells and selecting suitable interfacial materials for electrode modification in photodetectors.
关键词： Conjugated polymer electrolyte,Transient photocurrent dynamics,Steady-state device parameters,α-FAPbI3 perovskite photodetectors,Interfacial modification
更新于2025-09-23 15:21:01
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Efficiency and spectral performance of narrowband organic and perovskite photodetectors: a cross-sectional review
摘要： The capability of detecting visible and near infrared light within a narrow wavelength range is in high demand for numerous emerging application areas, including wearable electronics, the Internet of Things, computer vision, artificial vision and biosensing. Organic and perovskite semiconductors possess a set of properties that make them particularly suitable for narrowband photodetection. This has led to rising interest in their use towards such functionality, and has driven remarkable progress in recent years. Through a comparative analysis across an extensive body of literature, this review provides an up-to-date assessment of this rapidly growing research area. The transversal approach adopted here focuses on the identification of: (a) the unifying aspects underlying organic and perovskite narrowband photodetection in the visible and in the near infrared range; and (b) the trends relevant to photoconversion efficiency and spectral width in relation to material, device and processing strategies. A cross-sectional view of organic and perovskite narrowband photodetection is thus delineated, giving fresh insight into the status and prospects of this research area.
关键词： narrowband organic photodetectors,narrowband perovskite photodetectors,NIR photodetectors,colour sensors,spectral selectivity
更新于2025-09-23 15:19:57
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Solutiona??Processed Flexible Broadband Photodetectors with Solutiona??Processed Transparent Polymeric Electrode
摘要： Room-temperature solution-processed flexible photodetectors with spectral response from 300 to 2600 nm are reported. Solution-processed polymeric thin film with transparency ranging from 300 to 7000 nm and superior electrical conductivity as the transparent electrode is reported. Solution-processed flexible broadband photodetectors with a 'vertical' device structure incorporating a perovskite/PbSe quantum dot bilayer thin film based on the above solution-processed transparent polymeric electrode are demonstrated. The utilization of perovskite/PbSe quantum dot bilayer thin film as the photoactive layer extends spectral response to infrared region and boosts photocurrent densities in both visible and infrared regions through the trap-assisted photomultiplication effect. Operated at room temperature and under an external bias of -1 V, the solution-processed flexible photodetectors exhibit over 230 mA W-1 responsivity, over 1011 cm Hz1/2/W photodetectivity from 300 to 2600 nm and ≈70 dB linear dynamic ranges. It is also found that the solution-processed flexible broadband photodetectors exhibit fast response time and excellent flexibility. All these results demonstrate that this work develop a facile approach to realize room-temperature operated ultrasensitive solution-processed flexible broadband photodetectors with 'vertical' device structure through solution-processed transparent polymeric electrode.
关键词： perovskite photodetectors,broadband photodetectors,PbSe quantum dots,flexible electronics
更新于2025-09-23 15:19:57
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Improving the performance of ultra-flexible perovskite photodetectors through cation engineering
摘要： High performance ultra-flexible lightweight perovskite photodetectors hold promising applications on arbitrary substrates include unmanned aerial vehicles. Herein, we report a facile method to improve the performances of perovskite photodetectors on flexible ultrathin (50 μm) polyimide substrates by tuning the composition with different ratios of cations. In the presence of lead thiocyanate, a certain amount of formamidinium introduction could sufficiently enhance the methylammonium lead triiodide perovskite film quality with prolonged carrier lifetime. Perovskite photodetector with response time of ton=89 ms and toff=47 ms is achieved with a very simple device architecture. In addition, our flexible photodetectors maintain good performances after rigorous folding and bending, demonstrating excellent mechanical properties, which can be very useful for a variety of applications.
关键词： compositional engineering,mechanical stability,ultra-flexible detectors,perovskite photodetectors
更新于2025-09-23 15:19:57
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High performance CsPbBr <sub/>3</sub> quantum dots photodetectors by using zinc oxide nanorods arrays as an electron-transport layer
摘要： The electron transport layer (ETL) in perovskite photodetectors is playing a vital role in highly efficient electron extraction. Herein, this work reports a perovskite photodetector based on hydrothermal-fabricated ZnO nanorods (NRs) as the ETL and hot-injection-fabricated CsPbBr3 quantum dot (QD) as the photoabsorber. The crystalline structure, morphologies, and photoluminescence (PL) of the materials and the physics mechanism of highly efficient electron extraction in the devices are characterized and analyzed. The PL and time-resolved PL confirm the reduced recombination and enhanced electron transport to the indium tin oxide anode. The photodetectors based on ZnO NRs/CsPbBr3 QDs exhibit enormous enhancement in the response parameters such as a rise time of 12 ms, a decay time of 38 ms, and an on/off ratio of 3000, compared with the photodetectors based on ZnO films/CsPbBr3 QDs. These results indicate that the fabricated ZnO NRs/CsPbBr3 QDs heterojunction has a wide prospect of future applications in photodetectors.
关键词： electron transport layer,photoluminescence,ZnO nanorods,perovskite photodetectors,CsPbBr3 quantum dots
更新于2025-09-23 15:19:57
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Frequency- and Power-Dependent Photoresponse of a Perovskite Photodetector Down to the Single-Photon Level
摘要： Organometallic halide perovskites attract strong interests for their high photoresponsivity and solar cell efficiency. However, there was no systematic study of their power and frequency dependent photoresponsivity. We identified two different power-dependent photoresponse types in methylammonium lead iodide perovskite (MAPbI3) photodetectors. In the first type, photoresponse remains constant from 5 Hz to 800 MHz. In the second type, absorption of a single photon can generate a persistent photoconductivity of 30 pA under an applied electric field of 2.5×104 V/cm. Additional absorbed photons, up to 8, linearly increase the persistent photoconductivity, which saturates with absorption of more than 10 photons. This is different than single photon avalanche detectors (SPADs) because the single photon response is persistent as long as the device is under bias, providing unique opportunities for novel electronic and photonic devices such as analog memories for neuromorphic computing. We propose an avalanche-like process for iodine ions and estimate that absorption of a single 0.38 aJ photon triggers motion of 108-9 ions, resulting in accumulations of ions and charged vacancies at the MAPbI3/electrode interfaces to cause band bending and change of material electric properties. We have made the first observation that single-digit photon absorption can alter the macroscopic electric and optoelectronic properties of a perovskite thin film.
关键词： Perovskite,photodetectors,impact ionization,ion migration,single photon sensitivity
更新于2025-09-19 17:13:59
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Ultralong CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> nanowires synthesized by a ligand-assisted reprecipitation strategy for high-performance photodetectors
摘要： Organic-inorganic hybrid perovskite nanowires with well-defined structures have attracted considerable attention for optoelectronic applications. Perovskite nanowires integrated into practical optoelectronic devices are often hindered by the poor crystalline quality. Herein, a ligand-assisted reprecipitation strategy (LARP) is employed to prepare ultralong and freestanding CH3NH3PbI3 nanowires in large-scale. Oleylamine is adopted as an inhibitor, which can create a passivation layer on the surface of CH3NH3PbI3, to slow down the crystallization rate of CH3NH3PbI3 nanowire. With the low crystallization rate, several millimeters long and high-quality CH3NH3PbI3 nanowires with smooth surfaces can be synthesized in a large scale. Photodetectors fabricated on oleylamine assistant synthesized CH3NH3PbI3 nanowires exhibit high detectivity, which is five times higher than that of none oleylamine assistant synthesized CH3NH3PbI3 nanowires photoanode.
关键词： Organic-inorganic hybrid perovskite,photodetectors,nanowires,ligand-assisted reprecipitation strategy,optoelectronic applications,oleylamine
更新于2025-09-19 17:13:59