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Surface passivation of a Cu(In,Ga)Se2 photovoltaic absorber using a thin indium sulfide layer
摘要： The present study demonstrates the surface passivation of Cu(In,Ga)Se2 (CIGS) photovoltaic absorbers using a thin In2S3 layer and its effect on the performance of the CIGS device. Two types of CIGS samples with different surface roughness values prepared by conventional selenization of metal precursors (2-step) and three-stage co-evaporation (3-stage) were used to determine the influence of In2S3 surface passivation on CIGS surface roughness to minimize recombination at the interface of the CIGS and buffer layers. Three types of buffer layers, i.e., In2S3, CdS single layers, and an In2S3/CdS double layer, were prepared by chemical bath deposition on bare and Mo-coated substrates as well as glass/Mo/CIGS samples. The phase formation and properties of the as-prepared buffer layers were analyzed by XRD, Raman, and UV–Vis–NIR techniques. The power conversion efficiency of the CIGS solar cells was enhanced significantly for the 2-step-processed CIGS (from 6.97% to 9.89%) and slightly for the 3-stage-processed CIGS (from 10.1% to 11.0%) when passivated with In2S3. Further, both the In2S3 surface passivated 2-step- and 3-stage-processed CIGS devices exhibited high quantum efficiencies in the wavelength range of 400–550 nm. Therefore, surface passivation with In2S3 could improve the performance of CIGS devices.
关键词： Chalcopyrite,Surface passivation,Indium sulfide,Hybrid buffer,Cu(In,Ga)Se2,Double buffer
更新于2025-09-19 17:13:59
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Introduction of Multifunctional Triphenylamino Derivatives at the Perovskite/HTL Interface to Promote Efficiency and Stability of Perovskite Solar Cells
摘要： Surface passivation is a widely used approach to promote the efficiency and stability of perovskite solar cells (PSCs). In the present project, a series of new organic surface passivation molecules, which contain the same triphenylamino group with the hole transfer material of PSCs has been synthesized. These new passivation molecules are supposed to have both “carrier transfer” capability and “defect passivation” potential. We find that by using N-((4-(N,N,N-triphenyl)phenyl)ethyl)ammonium bromide (TPA-PEABr) as a surface passivation molecule, the efficiency of the PSCs can be improved from 16.69% to 18.15%, mainly due to an increased Voc (1.09 V compared with 1.02 V in control devices). The increased Voc is due to the reduced surface defect density and a better alignment for the related energy levels after introducing the TPA-PEABr molecules. Moreover, the stability of the PSCs can be significantly improved in TPA-PEABr passivated devices due to the hydrophobic nature of TPA-PEABr. Our results successfully demonstrate that passivation of the perovskite surface with a carefully designed multiple functional small organic molecule should be a useful approach for more stable PSCs with high efficiency.
关键词： Stability,Surface passivation,Perovskite solar cell,Triphenylamine derivative,Energy level alignment
更新于2025-09-19 17:13:59
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Investigation of LeTID where we can control it – Application of FZ silicon for defect studies
摘要： In this work we present results of a series of experiments to investigate the origin of the defects causing light and elevated temperature induced degradation (LeTID). It has been demonstrated that LeTID effects can be observed even in high purity monocrystalline silicon. The experiments are therefore performed on float-zone silicon and feature a variety of process schemes to test important hypotheses on LeTID and reproduce them under more defined conditions. Different surface passivation schemes based on aluminium oxide layers are combined with a designated hydrogenation treatment and subjected to different thermal processes on both p- and n-type wafers. The results on p-type wafers confirm several previous observations concerning, e.g., the influence of silicon nitride layers and the firing peak temperature. However, we do not observe a crucial influence of the specific firing temperature profile in the experiment. The investigated n-type wafers do not feature a typical LeTID behaviour but appear to be affected by the LeTID defect nonetheless. Firstly, we observe an improvement of the effective lifetime under LeTID testing conditions that is driven by an improvement of the bulk lifetime. Secondly, identical pattern are observed in lifetime images of n-type wafers directly after firing and of p-type wafers in the degraded state. These findings strongly indicate that LeTID defects can be present in the initial state of n-type wafers after firing.
关键词： surface passivation,float-zone silicon,defect studies,hydrogenation treatment,LeTID
更新于2025-09-19 17:13:59
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Surface passivation of zero-mode waveguide nanostructures: benchmarking protocols and fluorescent labels
摘要： Zero mode waveguide (ZMW) nanoapertures efficiently confine the light down to the nanometer scale and overcome the diffraction limit in single molecule fluorescence analysis. However, unwanted adhesion of the fluorescent molecules on the ZMW surface can severely hamper the experiments. therefore a proper surface passivation is required for ZMWs, but information is currently lacking on both the nature of the adhesion phenomenon and the optimization of the different passivation protocols. Here we monitor the influence of the fluorescent dye (Alexa Fluor 546 and 647, Atto 550 and 647N) on the non-specific adhesion of double stranded DNA molecule. We show that the nonspecific adhesion of DNA double strands onto the ZMW surface is directly mediated by the organic fluorescent dye being used, as Atto 550 and Atto 647N show a pronounced tendency to adhere to the ZMW while the Alexa Fluor 546 and 647 are remarkably free of this effect. Despite the small size of the fluorescent label, the surface charge and hydrophobicity of the dye appear to play a key role in promoting the DNA affinity for the ZMW surface. Next, different surface passivation methods (bovine serum albumin BSA, polyethylene glycol PEG, polyvinylphosphonic acid PVPA) are quantitatively benchmarked by fluorescence correlation spectroscopy to determine the most efficient approaches to prevent the adsorption of Atto 647N labeled DNA. Protocols using PVPA and PEG-silane of 1000 Da molar mass are found to drastically avoid the non-specific adsorption into ZMWs. Optimizing both the choice of the fluorescent dye and the surface passivation protocol are highly significant to expand the use of ZMWs for single molecule fluorescence applications.
关键词： fluorescent dyes,Zero mode waveguide,single molecule fluorescence,DNA adhesion,surface passivation
更新于2025-09-19 17:13:59
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<i>In situ</i> passivation of GaAsSb nanowires for enhanced infrared photoresponse
摘要： Surface passivation of semiconductor nanowires (NWs) is important for their optoelectronic properties and applications. Here, the in situ passivation effect of an epitaxial InP shell and the corresponding photodetector performance is experimentally studied. Compared with the unpassivated GaAsxSb1-x core-only NWs, the GaAsxSb1-x/InP core/shell NWs have shown much stronger photoluminescence and cathodoluminescence intensities. Correspondingly, the fabricated single GaAsxSb1-x/InP core/shell NW photodetector shows a responsivity of 325.1 A/W (@ 1.3 μm and 1.5 V) that is significantly enhanced compared to that of single GaAsxSb1-x core-only NW photodetectors (143.5 A/W), with a comparable detectivity of 4.7×1010 and 5.3×1010 cm√Hz/W, respectively. This is ascribed to the enhanced carrier mobility and carrier concentration by the in situ passivation, which lead to both higher photoconductivity and dark-conductivity. Our results show that in situ passivation is an effective approach for performance enhancement of GaAs1-xSbx NW based optoelectronic devices.
关键词： semiconductor,surface passivation,infrared photodetector,GaAsSb,MOCVD,InP,nanowire
更新于2025-09-19 17:13:59
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Optimization of SnO2-based electron-selective contacts for Si/PEDOT:PSS heterojunction solar cells
摘要： Tin oxide (SnO2) is a potentially excellent electron-selective contact (ESC) for silicon (Si)-based solar cells due to its satisfactory energy band structure and good crystallinity. However, unsatisfactory electron extraction ability and limited surface passivating effect of SnO2 ESCs will limit the performance of corresponding solar cells. We increase the Fermi level of SnO2 by doping Ethylene diamine tetraacetic acid (EDTA), which endows EDTA-SnO2 better electron extraction ability than SnO2. Moreover, EDTA-SnO2/SiOx bilayer ESC prepared by combining a EDTA-SnO2 layer and a thin silicon oxide (SiOx) film provides better surface passivation than EDTA-SnO2 ESC without impairing the charge transport capability markedly. The planar Si/PEDOT:PSS heterojunction solar cells (HSCs) with EDTA-SnO2/SiOx bilayer ESCs exhibit a power conversion efficiency (η) of 11.52%, which improves 13.7% in comparison with the η (10.13%) of HSCs with SnO2 ESCs, mainly caused by the increase in Voc and FF by 18 mV and 5.4% respectively.
关键词： Tin oxide,Electron-selective contact,Surface passivation,Silicon heterojunction solar cells,Fermi level
更新于2025-09-16 10:30:52
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[IEEE 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD) - Kyoto, Japan (2019.7.2-2019.7.5)] 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD) - Challenges and prospects of very thin (<50 μm) crystalline silicon solar cells
摘要： Thin crystalline silicon (c-Si) solar cells are highly attractive not only for reducing the material cost but also for realizing light-weight and flexible PV modules. Amorphous silicon/c-Si heterojunction (SHJ) architecture is suited to thin c-Si cells because of its excellent surface passivation capability. In this paper, we discuss the potential of very thin c-Si cells using the SHJ architecture.
关键词： solar cells,crystalline silicon,thin wafers,surface passivation,heterojunction
更新于2025-09-16 10:30:52
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Hexagonal Boron Nitride for Surface Passivation of Two-dimensional van der Waals Heterojunction Solar Cells
摘要： Two-dimensional (2D) semiconductors can be promising active materials for solar cells due to their advantageous electrical and optical properties, in addition to their ability to form high-quality van der Waals (vdW) heterojunctions using a simple process. Furthermore, the atomically thin nature of these 2D materials allows them to achieve light-weighted and transparent thin-film solar cells. However, strategies appropriate for optimizing their properties have not been extensively studied yet. In this paper, we propose a method for reducing the electrical loss of 2D vdW solar cells by introducing hexagonal boron nitride (h-BN) as a surface passivation layer. This method allowed us to enhance the photovoltaic performance of a MoS2/WSe2 solar cell. In particular, we observed ~74 % improvement of the power conversion efficiency owing to a large increase in both short-circuit current and open-circuit voltage. Such a remarkable performance enhancement was due to the reduction of the recombination rate at the junction and surface of non-overlapped semiconductor regions, which was confirmed via time-resolved photoluminescence analysis. Furthermore, the h-BN top layer was found to improve the long-term stability of the tested 2D solar cell under ambient conditions. We observed the evolution of our MoS2/WSe2 solar cell for a month and found that h-BN passivation effectively suppressed its degradation speed. In particular, the degradation speed of the passivated cell was twice as low as that of a non-passivated cell. This work reveals that h-BN can successfully suppress the electrical loss and degradation of 2D vdW heterojunction solar cells under ambient conditions.
关键词： surface passivation,solar cell,MoS2,WSe2,2D material,van der Waals heterojunction,h-BN
更新于2025-09-16 10:30:52
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Si-based GeSn photodetectors towards mid-infrared imaging applications
摘要： The GeSn detector offers the high-performance Si-based infrared photodetectors with complementary metal-oxide-semiconductor (CMOS) technique compatibility. In this work, we reports a comprehensive study of Si-based GeSn mid-infrared photodetectors, which includes: i) the demonstration of a set of photoconductors with Sn compositions ranging from 10.5% to 22.3%, showing the cut-off wavelength has been extended to 3.65 μm. The maximum D* of 1.1×1010 cm?Hz1/2?W-1 measured at 77 K is comparable to that of commercial extended-InGaAs detectors; ii) the development of surface passivation technique on photodiode based on in-depth analysis of dark current mechanism, effectively reducing the dark current. Moreover, mid-infrared images were obtained using GeSn photodetectors, showing the comparable image quality with that acquired by using commercial PbSe detectors. This work is a major step towards Si-based mid-infrared photodetectors for imaging applications.
关键词： surface passivation,GeSn photodetector,high Sn composition,imaging,mid-infrared
更新于2025-09-16 10:30:52
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Effect of energy transfer on the optical properties of surface-passivated perovskite films with CdSe/ZnS quantum dots
摘要： Surface passivation is an effective method to protect the surfaces and improve the luminescence properties of perovskite (PS) films. CdSe/ZnS core-shell quantum dots (QDs) have been employed for surface passivation of PS films because of their size-dependent tunable bandgaps. Herein, the energy transfer (ET) behavior of CH3NH3PbI2Br PS films covered with CdSe/ZnS QDs (QD/PS hybrid structures) is characterized by using photoluminescence (PL) and time-resolved PL spectroscopy. The PL decay time and the integrated PL intensity of the QD/PS hybrid structure increase compared with those of the bare PS films, owing to ET from the QDs to the PS and reduced charge traps. The ET efficiency increases from ~7% to 63% for the QD/PS hybrid structure when the core diameter of the QDs decreases from 6.5 to 2.7 nm, respectively. This can be explained by the charge transfer rate enhancement due to the control of energy level alignment of QDs. These results allow us to understand fundamental mechanisms such as ET from QDs to PS films as a function of the size of the QD.
关键词： CdSe/ZnS quantum dots,perovskite films,energy transfer,photoluminescence,surface passivation
更新于2025-09-12 10:27:22