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Integration of graphene with semiconducting quantum dots (QDs) provides an elegant way to access the intrinsic properties of graphene and optical properties of QDs concurrently to realize the high-performance optoelectronic devices. In the current article, we have demonstrated the high-performance photodetector based on graphene: CdSe QDs/CdS nanorod heterostructures. The resulting heterojunction photodetector with device configuration ITO/graphene: CdSe/CdS nanorods/Ag show excellent operating characteristics including a maximum photoresponsivity of 15.95 AW−1 and specific detectivity of 6.85 × 1012 Jones under 530 nm light illumination. The device exhibits a photoresponse rise time of 545 ms and a decay time of 539 ms. Furthermore, the study of the effect of graphene nanosheets on the performance enhancement of heterojunction photodetector is carried out. The results indicate that, due to the enhanced energy transfer from photoexcited QDs to graphene layer, light absorption is increased and excitons are generated led to the enhancement of photocurrent density. In addition to that, the graphene: CdSe QDs/CdS nanorod interface can facilitate charge carrier transport effectively. This work provides a promising approach to develop high-performance visible-light photodetectors and utilizing advantageous features of graphene in optoelectronic devices. [ABSTRACT FROM AUTHOR]

In this paper, we report efficient high-speed top-illuminated p-i-n photodiodes with high responsivity fabricated from germanium (Ge) films grown directly on silicon-on-insulator substrates. The devices were characterized with respect to their dark current, responsivity, and 3-dB bandwidth (BW) in the near infrared. For a 20-\mu\m-diameter device at room temperature, the dark current densities were approximately 38.3 \mA/\cm^2 at -1 V. The responsivity (\mmb R) at 1.55 \mu \m was 0.30 A/W, corresponding to a quantum efficiency of 24%. The 3-dB BW of the detector with 20-\mu\m diameter is as high as 23.3 GHz. [ABSTRACT FROM AUTHOR]

[Display omitted] • CsBi 3 I 10 was introduced as a lead-free alternative for photodetectors. • High-quality thin film was deposited on flexible PET via hot solution spin-coating. • Exploring the wide spectral response from 290 nm UV to 650 nm visible. • Stability ensured performance post extensive light and bending cycles. • Photodetector showcased dynamic imaging capability at room temperature. By employing a hot spin-coating method, CsBi 3 I 10 thin-film photodetector was fabricated onto flexible PET substrate. The resulting nontoxic photodetector demonstrated exceptional optoelectronic performance, featuring an I light / I dark ratio of 1.8 × 103, a responsivity of 18.3 mA/W and a detectivity of 2.95 × 108 Jones. It also showed a broad spectral response and maintained consistent performance after 506 light switching cycles and 1000 bending cycles. The dynamic imaging capability of the device was further validated, illustrating its potential for diverse applications. This work pioneers the application of CsBi 3 I 10 perovskite thin-film in flexible photodetectors, offering a green, stable and high-performance solution for next-generation optoelectronic devices. [ABSTRACT FROM AUTHOR]

• Chemical vapor deposition (CVD) technique was adopted to grow monolithic CsPbBr 3 thin films on glass substrates. • The vertically stacked device with ITO/SnO 2 /CsPbBr 3 /CuSCN/Ag configuration exhibits a photoresponsivity of 10.13 A/W at 0.05 V bias and 96 mA/W at 0 V bias. • The response time of the device in planar geometry is 241/205 ms, while the vertically stacked device has a response time of 20.51/21 ms at 0.05 V bias and 20.51/30 ms at 0 V bias. The high-quality monolithic growth of perovskite films with larger grains on any substrate is a challenging task due to the instability of morphology, carrier mobility and chemical stability. In this work, we demonstrated the strategy to grow CsPbBr 3 films with micron-sized grains along the (0 0 2) surface by chemical vapor deposition. The structural and optical characterizations have shown that the as-grown CsPbBr 3 thin films are compact and packed without pin holes and have excellent optical quality for use in high-performance optoelectronic devices. The planar photodetector with the device configuration Ag/CsPbBr 3 /Ag shows a high photoresponsivity of 506.32 A/W and a specific detectivity of 8.29 × 1012 Jones at an incident light illumination of 22.3 µW/cm2. On the other hand, the vertically stacked device with ITO/SnO 2 /CsPbBr 3 /CuSCN/Ag configuration exhibits a photoresponsivity of 10.13 A/W at 0.05 V bias and 96 mA/W under 0 V bias. Specifically, the response time of the device in planar geometry is 241/205 ms, while the vertically stacked device has a response time of 20.51/21 ms at 0.05 V bias and 20.51/30 ms at 0 V bias. The results provide a new strategy for the growth of high-quality perovskite thin films and their effective application for high-performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

In the recent past, layered zinc-based vanadium spinel oxides (ZnVOs) have shown an intriguing way to accomplish the challenges of energy conversion, storage, and utilization issues. Here, through first-principles calculations, a comprehensive study has been carried out to investigate the AV 2 M (where A = Zn, Zn 2 , Zn 3 , Zn 4, and M = O 4 , O 6 , O 7 , O 8 , O 9 respectively) electronic, photocatalytic, and optical properties. Formation energies with a negative sign express that the final compounds from the pure elements are possible and cohesive energies revealed that compounds are energetically stable. Spin-polarized calculations are also taken into account for better approximation of the electronic properties (band structure and density of states). All layered structures show indirect bandgap for spin-up calculations in range 0.3 eV–2.4 eV, while spin-down calculations show mix trends in range 2.3 eV–3.50 eV. An appropriate band edge with large enough kinetic over-potentials of the oxygen evolution reaction (ΔE V ≥ 1.244 eV) makes them potential candidates as photoanode for water splitting. ZnV 2 O 4 is more suitable for OER as it has small kinetic overpotential as compared to the oxidation potential of water. Interestingly, all ZnVOs display a dramatically large coefficient (~105 cm−1) for optical absorption. Photogenerated electrons and holes on the layered zinc-based vanadium spinel oxide surfaces could make these spinel oxides promising materials for photocatalytic water splitting and solar energy conversion. [Display omitted] • Photocatalytic and optical properties of different phases of ZnVOs. • ZnVOs show good photocatalytic activity in visible and UV region. • ZnVOs could be potential candidates for water splitting (OER). • All ZnVOs display high coefficient of absorption (x 105 cm−1). • ZnVOs could be potential candidates for solar optical devices. [ABSTRACT FROM AUTHOR]

• First ever optical, mechanical and anisotropic properties of cubic GeX (X = S, Se) are studied. • 2D & 3D surface visualization suggest that both chalcogenides are elastically anisotropic. • Debye temperature (θ D) of π-GeS and π-GeSe are 262.28 K and 264.46 K, respectively. • Germanium chalcogenides are promising candidate for optoelectronic, thermoelectric devices. Newly discovered cubic phase of Germanium monochalcogenide (π-GeS and π-GeSe) with a moderate bandgap, less toxicity, and novel electronic properties have earned significant attention of researchers due to appropriate nature for the energy-related applications such as photovoltaic, optoelectronic and thermoelectric devices. The structural, electronic (band structure and DOS), optical and elastic properties of π-GeS and π-GeSe have been studied by ultrasoft pseudopotential technique. The band structure calculations confirm that both π-GeS and π-GeSe are indirect in nature with bandgap energies 1.38 and 1.04 eV respectively. The first-time calculated elastic constants of π-GeS and π-GeSe satisfy their mechanical stability criteria (Born stability). The elastic moduli (bulk, Young's, shear), Lame's parameters, Poisson's ratio, Debye temperature, and average sound velocity are determined by Voigt-Reuss-Hill approximation. The shear and Young's elastic properties reveal that both π-GeS and π-GeSe are anisotropic, which is also confirmed from 2D and 3D surface visualization. The calculated Debye temperature (θ D) of π-GeS and π-GeSe are 262.28 K and 264.46 K at 300 K, respectively. Additionally, the longitudinal and transversal waves sound velocities are calculated for the first time in [1 1 1], [1 1 0] and [1 0 0] directions. The present results reveal that π-GeS and π-GeSe could be appropriate candidates for exploitation in energy storage, optoelectronic and thermoelectric devices. Particularly GeS, which has higher absorption peaks and optimum bandgap (1.38 eV) for practical photovoltaic and photo-sensing applications. The present work provides the pathways for theoretical and experimental studies on electronic devices based upon cubic chalcogenides. [ABSTRACT FROM AUTHOR]

Abstract Recently, Tin Monoxide (SnO) has attained a considerable interest due to its striking electronic, optical, thermoelectric and gas sensing properties in various advanced technological applications. In this study, we focus on the first principles calculations to examine the structural, electronic and optical properties of the pristine, 1S, 2S, and 3S doped SnO. The plane-wave ultra-soft pseudopotential method is used under the GGA-PBE exchange-correlation energy with supercell approach. Bandgap reduces with the increase in the concentration of doping from 0.460 eV to 0.330 eV, 0.064 eV for 1S, 2S respectively and shows metallic behavior for 3S doped SnO. Formation and cohesive energies decrease in order of Sn 15 S 1 O 16 < Sn 14 S 2 O 16 < Sn 13 S 3 O 16, which shows that the most suitable and favorable configuration is of Sn 15 S 1 O 16. The static dielectric constant ε 1 (0) and refractive index n (0) are 7.71, 7.82, 8.48, 9.42 eV and 2.76, 2.80, 2.91, 3.07 respectively, which are showing increasing trends. The absorption spectrum and optical conductivity curves of S doping show a significant blueshift towards ultraviolet spectrum. The optical properties and bandgap narrowing effect suggest that the sulfur-doped SnO can be a promising new semiconductor in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

With the advantages of stable structure, large optical absorption coefficient, optimal bandgap, and high See-Beck coefficient, antimony selenide (Sb 2 Se 3) has good prospects for applications in solar cells, photodetectors, thermoelectric devices, etc. In this work, high quality Sb 2 Se 3 nanowires were fabricated by a hydrothermal method and the fabrication of a single nanowire photodetector was reported. From the experimental data, a band gap of Sb 2 Se 3 nanowires was calculated to be 1.04 eV. The Sb 2 Se 3 single nanowire detector has a dark current of 230 pA, a photocurrent of 45 nA, and a photoresponsivity of 196 mA/W under the light irradiation intensity of 14.4 mW/cm2 @ 532 nm. The photoresponse time of PDs is observed to be 90 ms and 100 ms. The results could enable the large-scale synthesis of high-purity Sb 2 Se 3 nanowires with excellent optical properties and their application in functional optoelectronic devices. [Display omitted] [ABSTRACT FROM AUTHOR]

Recently discovered novel π-SnS (cubic phase) has gained much attention due to suitable nature for several optoelectronic devices and thermoelectric applications. Local density approximation (LDA) and generalized gradient approximation (GGA) with ultra-soft pseudo-potential (UPP) technique within density functional theory (DFT) are used to study the structural, electronic, optical, and elastic properties of π-SnS. The structural properties show good consistency with previous results. The band structure study shows that its nature is indirect with bandgap 1.073/1.37 eV (LDA/GGA). The calculated elastic constants satisfy the Born stability criteria which are determined for the first time as per our knowledge. On the basis of Voigt-Reuss-Hill approximation, bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, Lame’s coefficients, average sound velocity and Debye temperature are determined. In LDA/GGA the value of Bulk modulus is estimated 55.32/20.98 GPa, which is in good agreement to that calculated with Birch-Murnaghan equation of state (EOS). The 2D and 3D surface visualization of bulk, shear and Young’s moduli suggest that π-SnS is elastically anisotropic. In LDA/GGA the value of Debye temperature (θ D ) is estimated as 361.01/299.39 K. The thermal conductivity of π-SnS could be high due to high Debye temperature (θ D ) relative to α-SnS (θ D  ∼ 270 K). Additionally, for the first time transversal and longitudinal wave velocities in [1 0 0], [1 1 0] and [1 1 1] directions are calculated. In the view of present studies π-SnS could be suitable candidate for exploitation in optoelectronic, thermoelectric and energy storage devices. [ABSTRACT FROM AUTHOR]