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Perovskite quantum dots (QDs) and organic materials have great research potential in the field of optoelectronic devices. In this paper, MEH-PPV/CsPbBr3 heterojunction photodetectors (PDs) are prepared by spin coating method based on the good photoelectric properties of CsPbBr3 perovskite QDs and MEH-PPV. The MEH-PPV/CsPbBr3 heterojunction improves the energy level arrangement, and CsPbBr3 QDs can passivate the surface defects of MEH-PPV films to achieve effective charge separation and transfer, thus inhibiting the dark current and improving the photoelectric performance of the device. Under 532 nm laser irradiation, the responsivity (R) of MEH-PPV/CsPbBr3 heterojunction PD is 11.98 A W−1, the specific detectivity (D *) is 6.98 × 1011 Jones, and the response time is 15/16 ms. This work provides experience for the study of perovskite QDs and organic materials heterojunction optoelectronic devices. [ABSTRACT FROM AUTHOR]

Self-powered solar-blind ultraviolet photodetectors are considered for potential applications in secure communication and space detection. However, high-quality p-type wide bandgap semiconductors are nonexistent due to the self-compensation effect, which makes the design of p-n homojunction photodetectors a challenging proposition to date. In this work, a self-powered solar-blind ultraviolet photodetector is fabricated and discussed, based on a novel heterojunction of (InxGa1−x)2O3 ternary alloy films with two different compositions, which has a flexible design and can be easily fabricated for different applications. The heterojunction consists of an amorphous (In0.23Ga0.77)2O3 on the top of a bixbyite (In0.67Ga0.33)2O3 film prepared by radio frequency magnetron sputtering. The amorphous (In0.23Ga0.77)2O3/bixbyite (In0.67Ga0.33)2O3 heterojunction photodetector exhibits a responsivity of 5.78 mA/W, a detectivity of 1.69 × 1011 cm Hz1/2 W−1, and a high solar-blind UV (248 nm)/visible light (450 nm) rejection ratio of 1.39 × 103 at zero bias, suggesting decent spectral selectivity and high performance. The responsivity and peak wavelength of this photodetector can be tuned by the film thickness of the amorphous (In0.23Ga0.77)2O3. This work provides a new design for self-powered solar-blind UV detectors based on ternary alloy heterojunctions. [ABSTRACT FROM AUTHOR]

Metal oxide semiconductors have attracted growing attention due to their excellent electrical and optical properties, low-cost fabrication, and good stability, which grant them great application potential in photodetectors (PDs). However, broadband photoelectrochemical (PEC)-type PDs based on metal oxide semiconductors are deficient. In this work, we synthesized two-dimensional (2D) CuO nanosheets (NSs) by annealing Cu-based metal–organic frameworks (Cu-MOFs) and first demonstrated broadband PEC PDs based on 2D CuO NSs. The thicknesses of 2D CuO NSs are 2–6 nm. 2D CuO PEC PDs show a broadband photoresponse from 365 to 850 nm with a responsivity of 2.7 mA/W and a response time of 60/400 ms, which surpass most 2D material-based PEC PDs. Moreover, CuO NSs PEC PDs exhibit outstanding multicycle stability and long-term stability for 1-month storage with negligible decay, exceeding all recently reported 2D material-based PEC PDs. These results endow 2D CuO NSs with great potential in underwater photodetection. [ABSTRACT FROM AUTHOR]

High-quality $\beta $ -Ga2O3 films were prepared via the metal organic chemical vapor deposition method and construction of metal–semiconductor–metal–structured photodetectors (PDs) with varying parameters, including length, width, and distance of the Ti/Au interdigital electrodes. Under a 10 V bias and UV light illumination ($50~\mu $ W/cm2), the peak response of PDs is present in the solar-blind region (254 nm), and the responsivity is as high as $1.87\times10$ 5 A/W. The cut-off wavelength is ~266 nm, with a deep UV/visible light responsivity rejection ratio (R254 nm/R400 nm) of ~102. The light–dark current ratio reaches 105, the detectivity is about $3.37\times10$ 14 Jones, and the rise and decay response time is < 1 s. These high performances are attributed to defect center trapping carriers, yielding inconsistent electron and hole collection efficiency. Additionally, the nonlinear effect between light intensity and photocurrent that is induced by avalanche ionization under a high electric field (50 V) is demonstrated. This study might be of great value for the design and fabrication of high-performance solar-blind UV PDs. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) In2Se3 has received considerable attention due to its suitable band gap, good photoresponse, and high stability, making it a good candidate for high-performance photodetectors. Self-powered 2D In2Se3-based photodetectors consisting of heterojunctions usually require a complex fabrication process, hindering their application. In this work, we synthesize 2D In2Se3 nanosheets by an electrochemical exfoliation method and fabricate self-powered In2Se3 photoelectrochemical (PEC) photodetectors by a simple drop-casting method. The self-powered In2Se3 PEC photodetectors show a broadband photoresponse from ultraviolet (365 nm) to near-infrared (850 nm) with a high responsivity of 1.88 mA/W, fast response speed of 1 ms, and good stability, surpassing most 2D material-based PEC photodetectors. Our results demonstrate that self-powered In2Se3 PEC photodetectors hold great promise in next-generation high-performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

In this work, FTO/amorphous-(In 0.23 Ga 0.77) 2 O 3 /spiro-OMeTAD photodetector capable of broadband detection (200–400 nm) with wavelength discrimination is fabricated. Incorporation of spiro-OMeTAD as hole transport layer improved self-powered performance of FTO/amorphous-(In 0.23 Ga 0.77) 2 O 3 /spiro-OMeTAD broadband photodetector. Under 260 nm illumination, the photodetector exhibited a responsivity (R) of 0.63 mA/W and a detectivity (D *) of 5.40 × 1010 cm Hz1/2 W−1 under zero bias. The values enhanced to R = 0.61 mA/W and D * = 5.50 × 1010 cm Hz1/2 W−1 under 320 nm illumination. For 400 nm illumination, the values were R = 0.35 mA/W, D * = 4.90 × 1010 cm Hz1/2 W−1 under zero bias. Moreover, FTO/amorphous-(In 0.23 Ga 0.77) 2 O 3 /spiro-OMeTAD photodetector demonstrated faster response speed with rising time decreased to 0.02 s and decay time decreased to 0.04 s, compared to FTO/amorphous-(In 0.23 Ga 0.77) 2 O 3 photodetectors under 260 nm illumination. The wavelength discrimination capability within 200–400 nm range was attributed to type-I staggered band alignment in FTO/amorphous-(In 0.23 Ga 0.77) 2 O 3 interface and type-Ⅱ staggered band alignment in spiro-OMeTAD/amorphous-(In 0.23 Ga 0.77) 2 O 3 interface, through choosing illumination on FTO or spiro-OMeTAD sides. In conclusion, FTO/amorphous-(In 0.23 Ga 0.77) 2 O 3 /spiro-OMeTAD heterogeneous junction, using a combination of p-type polymer and inorganic wide bandgap semiconductors, shows great potential for self-powered and high-performance broadband photodetectors. [ABSTRACT FROM AUTHOR]

Photoelectrochemical-type (PEC) photodetectors (PDs) show great promise in underwater optoelectronic devices, but most reports of PEC PDs use acid or basic solutions as electrolytes, hindering their practical application in marine scenarios. In this letter, we reported high-performance 2D CuSe-based PEC PDs with use of the electrolyte of simulated seawater for the first time. The 2D CuSe nanosheet array (NSA) is synthesized by a facile electrodeposition method. The PEC PDs based on 2D CuSe NAS has a superior responsivity of 9.5 mA/W for 455 nm light in the simulated seawater, and exhibits a broadband photoresponse in 365–850 nm, surpassing most TMCs-based PEC PDs. The superior photoresponse originates from the vertical NSA structure, providing more interfacial active sites and higher light absorption. In addition, 2D CuSe NSA-based PEC PDs possess self-powered ability, fast response speed, good stability, and underwater optical communication capability. This work demonstrates the great potential of 2D CuSe NSA in PEC-type optoelectronic devices. [Display omitted] [ABSTRACT FROM AUTHOR]

The ferroelectric perovskite material Cs 2 AgBiBr 6 has received much attention because of its low poisonous nature and environmental stability. In this paper, we prepared high-quality Cs 2 AgBiBr 6 thin films for self-powered photodetectors using a low-pressure-assisted method, investigated their optical, electrical, and pyroelectric properties, and characterized the film morphology and crystallization. The device modulates the photoelectric process without an external power supply, and has a maximum switching ratio of 1.72 × 106, a response rate of 0.158 A/W, a specific detectivity of 1.39 × 1011 Jones, an external quantum efficiency of 52.8 %, and a fast response time of 15.4/16.8 μs when irradiated with 532 nm light, which is much better than that of previous self-powered devices with the same material on/off ratio and specific detectivity. It is worth mentioning that the pyroelectric effect was observed in the infrared band. In addition, the devices exhibited high stability to water and oxygen in an air environment (25 °C, 60 % humidity), retaining more than 95 % of the initial performance after one month of placement. Our study demonstrates that the lead-free perovskite Cs 2 AgBiBr 6 is a promising and environmentally friendly alternative for the preparation of highly stable self-powered photodetectors and is also of great research value in the field of pyroelectric detection. • The pyroelectric effect of the Cs 2 AgBiBr 6 thin-film device was observed in the infrared band. This paper explains the effect in terms of light-induced changes in the temperature gradient. • The Cs 2 AgBiBr 6 thin films are prepared by a low-pressure-assisted method and the devices have good morphology and properties. • The device modulates the photoelectric process without an external power supply and has a maximum switching ratio of 1.72 × 106 and a response time of 15.4/16.8 μs. The device retains more than 95 % of the initial performance after one month of placement in an air environment (25 °C, 60 % humidity). [ABSTRACT FROM AUTHOR]

In recent years, Cs 2 SnI 6 has emerged as a promising photosensitive material due to its low toxicity and stability. However, Cs 2 SnI 6 is severely compromised in the DMF solvent, significantly declining stability and efficiency. To address this issue, a straightforward and cost-effective approach was employed to synthesize Cs 2 SnI 6 powder. Cs 2 SnI 6 photodetectors (PDs) were fabricated by dissolving the powders in anhydrous ethanol (ETOH), n-hexane (N-H), deionized water (D.I. water) or N, N-Dimethylformamide (DMF) solvents respectively, and the devices were demonstrated with excellent photo performance in the visible-near infrared (Vis-NIR) band. Contrast experiments demonstrated that fabricated PD by dissolution in ETOH showed superior performance. Under the irradiation of the 405 nm laser, the device shows a specific responsivity (R) of 8.53 A/W and a specific detectivity (D*) of 8.87×1011 Jones. This strategy will provide a new way to improve the photo performance of tin-based perovskite PDs. [Display omitted] • The Cs 2 SnI 6 photodetector was prepared using environmentally friendly perovskite materials. • Four solvents were used for comparative tests to derive the optimal solvent to solve the problem of the film degradation of Cs 2 SnI 6 in DMF or DMSO. • The PD shows a responsivity of 8.53 A/W and a specific detectivity of 8.87×1011 Jones. [ABSTRACT FROM AUTHOR]

[Display omitted] • In 2 Se 3 nanoparticles were prepared by facile hydrothermal method. • Self-powered In 2 Se 3 -based PEC photodetectors show good photoresponse in the visible light region. • In 2 Se 3 -based PEC photodetectors exhibit a fast response speed (100 ms) and good stability. In this study, In 2 Se 3 nanoparticles were prepared by hydrothermal synthesis, In 2 Se 3 -based PEC PDs were prepared and the corresponding photoresponse was studied. The size of In 2 Se 3 nanoparticles is about 271 nm. Self-powered In 2 Se 3 -based PEC PDs show good photoresponse in the visible light region (455–630 nm) with a high responsivity of 25.48 mA/W under 455 nm irradiation, fast response speed (100 ms), and good stability, which exceeds other reported selenides-based PEC PDs, indicating that In 2 Se 3 nanoparticles PEC PDs have good application potential in underwater optoelectronic devices. [ABSTRACT FROM AUTHOR]

Platinum telluride (PtTe 2), as a newly emerged type II Dirac semimetal, has attracted much attention. Due to its excellent linear dispersive band structure and ultra-high carrier mobility, PtTe 2 show great potential in the new quantum phenomena, topological phase transitions, unconventional superconductivity and other photodetecting fields. In this paper, we report the negative photoelectric effect of photodetectors based on the type II Dirac semimetal PtTe 2 film under the laser irradiation of 405 nm, 532 nm and 808 nm. Under the condition of applying 1 V voltage, the R of the PtTe 2 device under 405 nm laser irradiation was 20 A/W and the D* was 6.9×109 Jones; the R of the PtTe 2 device under 532 nm laser irradiation was 1.3 A/W and the D* was 4.1×108 Jones; the R of the PtTe 2 device under 808 nm laser irradiation was 0.6 A/W and the D* was 2.1×108 Jones. Under normal atmospheric pressure and room temperature conditions, we observed a negative photoconductivity phenomenon for the PtTe 2 device, where the change in photoconductivity is attributed to the light-induced desorption of O or H 2 O molecules from the surface of the material. In addition, a single-site scanning imaging system based on a PtTe 2 photodetector was designed to test the detection capability of the device. The analysis of the photocurrent effect produced by the PtTe 2 device further deepens the understanding of the photoconductivity mechanism in the field of photodetection. [Display omitted] • The negative photoconductivity effect of PtTe2-based photodetectors in the visible and near-infrared bands was investigated. • PtTe2 thin films were grown on sapphire substrates using direct tellurisation. • The PtTe2 has a high responsiveness of 20 A/W. [ABSTRACT FROM AUTHOR]

Silver sulfide (Ag 2 S) quantum dots (QDs), as a new non-toxic and environmentally friendly QD material, has been widely applied in photoelectric device. We synthesized Ag 2 S QDs by simple chemical method, and constructed quantum dot-polymer heterojunction photodetector (PD) by combining with the Poly (MEH-PPV). The addition of Ag 2 S QDs improves the light absorption capacity of MEH-PPV in the visible to near infrared range. Then the photoelectric characteristics of the heterojunction photodetector were measured. The optical responsivity and specific detectivity of the device at 405,532,808 nm were 27.5 A/W,2.19 × 1010 Jones, 23.8 A/W,1.62 × 1010 Jones, 51.7 A/W,3.23 × 1010 Jones, respectively. This work will improve the capability of vulcanized MEH-PPV for broad spectrum measurement and weak light detection. [Display omitted] • Heterojunction devices were prepared by simple chemical method. • The absorption range of hybrid devices is expanded to near infrared. • The optical responsivity of the device at 808 nm reaches 51.7 A/W. [ABSTRACT FROM AUTHOR]