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Achieving a high open-circuit voltage in inverted wide-bandgap perovskite solar cells with a graded perovskite homojunction
摘要： Wide-bandgap (~1.7-1.8 eV) perovskite solar cells have attracted substantial research interest in recent years due to their great potential to fabricate efficient tandem solar cells via combining with a lower bandgap (1.1-1.3 eV) absorber (e.g., Si, copper indium gallium diselenide, or low-bandgap perovskite). However, wide-bandgap perovskite solar cells usually suffer from large open circuit voltage (Voc) deficits caused by small grain sizes and photoinduced phase segregation. Here, we demonstrate that in addition to large grain sizes and passivated grain boundaries, controlling interface properties is critical for achieving high Voc’s in the inverted wide-bandgap perovskite solar cells. We adopt guanidinium bromide solution to tune the effective doping and electronic properties of the surface layer of perovskite thin films, leading to the formation of a graded perovskite homojunction. The enhanced electric field at the perovskite homojunction is revealed by Kelvin probe force microscopy measurements. This advance enables an increase in the Voc of the inverted perovskite solar cells from an initial 1.12 V to 1.24 V. With the optimization of the device fabrication process, the champion inverted wide-bandgap cell delivers a power conversion efficiency of 18.19% and sustains more than 72% of its initial efficiency after continuous illumination for 70 h without encapsulation. Additionally, a semitransparent device with an indium tin oxide back contact retains more than 88% of its initial efficiency after 100 h maximum power point tracking.
关键词： wide-bandgap perovskite solar cells,perovskite homojunction,guanidinium bromide
更新于2025-10-22 19:40:53
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Thickness-modulated in-plane Bi<sub>2</sub>O<sub>2</sub>Se homojunctions for ultrafast high-performance photodetectors
摘要： Bi2O2Se thin film could be one of the promising material candidates for next-generation electronic and optoelectronic applications with the outstanding electrical and optoelectrical properties. However, the device performance based on the Bi2O2Se thin films was not fully explored in the photodetecting area. Considering that the electrical properties such as carrier mobility, work function and energy band structure of Bi2O2Se are thickness dependent, in-plane Bi2O2Se homojunctions consisting of layers with different thickness were successfully synthesized by CVD method across the terraces on the mica substrates, where terraces were created during the mica surface layer peeling off process. In this way, effective internal electrical fields were built up along the Bi2O2Se homojunctions, The Bi2O2Se in-plane homojunctions exhibiting diode-like rectification behavior with an on/off ratio of 102, what’s more, the photodetectors based on which were featured as highly sensitive and ultrafast with the maximum photoresponsivity of 2.5A/W and the lifetime of 4.8μs. Compared with the Bi2O2Se uniform thin films, the photo-electric conversion efficiency was greatly improved for the in-plane homojunctions.
关键词： thickness modulation,in-plane homojunction,photodetectors,Bi2O2Se
更新于2025-09-23 15:19:57
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An Efficient Room Temperature Ethanol Sensor Device Based on p-n Homojunction of TiO <sub/>2</sub> Nanostructures
摘要： In this paper, an efficient room temperature ethanol sensor device based on p-n homojunction of p-TiO2 nanoparticles (NPs) and n-TiO2 nanotubes (NTs) is reported. p-TiO2 NPs were prepared by low-temperature sol–gel method and coated on n-TiO2 NTs (NPs) grown by electrochemical anodization. Field emission scanning electron microscopy and X-ray diffraction authenticated the formation of stable homojunction between p-type anatase TiO2 NPs and n-type anatase TiO2 NTs. Current–voltage characteristics of the device, in the lower voltage range (0–1.26 V) for 30 °C, followed nonlinear characteristics (Schottky). With increase in voltages (>1.26 V) and temperature (40 °C–100 °C) such nonlinear behavior moves toward more linear ones. The gas sensing performance of the homojunction device was studied at room temperature with alcohols as the test species. The device offered the maximum response magnitude of ～57% (toward ethanol) at 100 ppm with appreciably fast response time and recovery time of ～30 and ～16 s, respectively. Dramatic increase in the effective depletion region area distributed throughout the nanotubular voids and the associated localized electric filed originated from the electrostatic charge separation therein (which helps in easy dissociation of target species) is possibly responsible for such efficient room temperature sensing performance.
关键词： room temperature,Ethanol sensing,fabrication and characterization,p-TiO2 nanoparticles (NPs)/n-TiO2 nanotubes (NTs),homojunction
更新于2025-09-19 17:15:36
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Construction of morphology-controlled nonmetal 2D/3D homojunction towards enhancing photocatalytic activity and mechanism insight
摘要： Highlights ? A novel nonmetal 2D/3D g-C3N4 homojunction was constructed via the facile surface in-situ polymerization process. ? The nonmetal 2D/3D g-C3N4 homojunction displayed the dramatically enhanced photocatalytic performance for degrading TC-HCl. ? The improved transfer and separation efficiency of charge carriers resulted from synergetic effect of 2D-3D structural coupling and energy band controlling. ? This work develops a feasible exemplificative strategy for fabricating new morphology-controlled at the interface between structural units owing to the matching chemical and electronic structures, nevertheless it still is difficult to fabricate the morphology-controlled nonmetal homojunction. Herein, a nonmetal 2D/3D homojunction is constructed via the facile surface Constructing homojunction is more favorable to transfer and separation of charge carriers nonmetal homojunctions to improve photocatalytic activity microspheres, mainly attributing to the improved transfer and separation efficiency of charge homojunction displays the dramatically enhanced photocatalytic performance for degrading tetracycline hydrochloride (TC-HCl) compared with single 2D CN nanosheets and 3D CC carriers resulted from synergetic effect of 2D-3D structural coupling and energy band controlling. Moreover, the important degradation pathway, intermediate products and surface of 2D g-C3N4 (2D CN) nanosheets. The obtained nonmetal 2D/3D CN/CC in-situ polymerization process, where 3D g-C3N4 (3D CC) microspheres tightly anchor on the photocatalytic mechanism are investigated in detail. This work develops a feasible exemplificative strategy for fabricating new morphology-controlled nonmetal homojunction to improve photocatalytic activity.
关键词： Degradation mechanism,TC-HCl,Nonmetal homojunction,g-C3N4,Morphology-controlled
更新于2025-09-19 17:13:59
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High-performance MoSe2 homojunction infrared photodetector
摘要： Two-dimensional (2D) materials with unique structural and physical properties are urgent to exploit and may be applied in the next-generation electronics and infrared detectors. The homojunction devices are ideal and promising candidates compared to heterojunction devices since there is no interface problems, such as unintentionally induced impurities and charge-trapped sites. In this work, we reported a high-performance MoSe2 homojunction infrared photodetector. MoSe2 homojunction devices directly consist of thick and thin MoSe2. MoSe2 homojunction diodes exhibit different rectified characteristics including forward and reverse rectifications, which are dependent on the back-gate voltage. Remarkably, MoSe2 homojunction photodetectors possess a broadband photoresponse with the wavelength from visible to near-infrared at room temperature. The responsivity of MoSe2 homojunction photodetectors at 940 nm laser illumination is approximately 2.25 A W-1. Additionally, the obtained specific detectivity of MoSe2 homojunction device is over 1010 Jones. Our findings provide an excellent way to fabricate feasible homojunction devices. Meanwhile, homojunction devices also show the wealthy potential in novel electronic and optoelectronic devices.
关键词： infrared photodetector,forward rectification,reverse rectification,MoSe2,homojunction
更新于2025-09-19 17:13:59
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High performance near infrared photodetector based on in-plane black phosphorus p-n homojunction
摘要： Black phosphorus (BP) has been considered as an appealing candidate for broadband photodetection from the visible to the infrared part of the spectrum owing to its tunable direct band gap and high carrier mobility. However, compared with other typical materials, the photoresponsivity of BP devices is rather weak. In this work, a near infrared photodetector with high performance based on in-plane BP p-n homojunction was investigated. The strong built-in electric field of the p-n junction can be modulated through bias and gate voltage, where the photo generated electron-hole pairs can be effectively separated, thus, leads to the enhanced photocurrent and faster photoresponse. Compared with the pristine BP, the photoresponsivity of the BP p-n homojunction under 1550 nm displays a 50-fold increment. The response time of the in-plane BP p-n homojunction photodetector exhibits two orders of magnitude improvement than that of the pristine BP and other lateral homogeneous BP p-n junction. Fascinatingly, the BP p-n photodetector also displays visible-infrared dual-band detection with well separated spectral response, opening up a feasibility of the intelligent identification of infrared targets.
关键词： In-plane homojunction,Dual-band detection,Near infrared photodetector,Black Phosphorus
更新于2025-09-16 10:30:52
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Magnetron sputtered Sb2Se3-based thin films towards high performance quasi-homojunction thin film solar cells
摘要： Sb2Se3 is a promising candidate for environment-friendly and cost-e?ciently thin ?lm photovoltaics thanks to its material advantages and superior optoelectronic properties. However, it has intrinsically low electrical conductivity, which leads to unsatisfactory device performance and limited scope of applications. Herein, we demonstrated an e?ective strategy of electrical conductivity-induced Sb2Se3-based photovoltaic performance improvement. Three Sb2Se3-based targets with chemical composition of Sb2Se3, Sb2Se3.3 and Sb2(Se0.9I0.1)3 have been ?rstly prepared by using high-temperature melting technique. Then the high-quality thin ?lms can be obtained through an e?ective Radio Frequency (RF) magnetron sputtering process. A novel Sb2Se3 quasi-homojunction thin ?lm solar cell was fabricated for the ?rst time and the highest power conversion e?ciency reaches already a highly interesting 2.65%. The combined features of unique quasi-homojunction device structure and advantageous full-vacuum preparation process further demonstrated its attractive potential for thin ?lm photovoltaic applications.
关键词： Sb2Se3,Quasi-homojunction,Magnetron sputtering,Thin ?lm solar cells,Electrical conductivity
更新于2025-09-12 10:27:22
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Gap‐Mode Plasmon‐Induced Photovoltaic Effect in a Vertical Multilayer Graphene Homojunction
摘要： Gap-mode plasmons that occur between metallic nanoparticles and metallic films separated by a thin spacer have been widely studied in the field of nano-optics and plasmonics for enhancing the light–matter interaction of graphene and other two-dimensional (2D) materials. However, efficient photovoltaic devices using such gap-mode plasmons have not been achieved because of structural difficulties. Here, a gap-mode plasmon-induced asymmetric vertical homojunction photovoltaic device using multilayer graphene is presented. In this structure, the multilayer graphene acts both as a photo-carrier generation layer and as a spacer for the gap-mode plasmon. The optical absorption of graphene is further enhanced by the presence of gap-mode plasmons, and the photoresponse time is extremely short because of the atomically short channel lengths across the vertical direction. The wavelength dependence of the gap-mode plasmon is also investigated for three devices with different metal electrodes by photocurrent measurement at five different wavelengths and numerical simulations. The device strategies implemented in this work can enhance the performance of graphene-based vertical photonic devices and can be applied to other 2D materials-based photonic devices.
关键词： vertical structures,homojunction,gap-mode plasmons,photovoltaics,multilayer graphene
更新于2025-09-12 10:27:22