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Effect of TaN intermediate layer on the back contact reaction of sputter-deposited Cu poor Cu2ZnSnS4 and Mo
摘要： Ultrathin tantalum nitride (TaN) intermediate layers (IL) with thicknes from 3 nm to 12 nm have been used to limit the undesirable interfacial reaction between molybdenum (Mo) and copper-zinc-tin-sulphide (CZTS). The morphology, chemical and structural properties of the samples were characterized by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction analysis, and scanning transmission electron microscopy (STEM). Time-of-flight secondary ion mass spectrometry (TOFSIMS), energy-dispersive X-ray spectroscopy (EDX), and electron energy loss spectroscopy (EELS) have been used for elemental analysis. Thin TaN IL show chemical reactivity towards sulphur (S) vapor at 600oC and the incorporation of S in TaN reduces the S concentration in Mo films at the sub-surface region and thus improves electrical conductivity of sulphurised Mo. The use of a non-stoichiometric quaternary compound CZTS target along with TaN IL enables to minimise thickness of MoS2 layer and reduce void formation at the Mo/CZTS interface. Furthermore, incorporation of TaN IL improves scratch hardness of CZTS/Mo films to soda-lime glass substrate.
关键词： interface engineering,MoS2,Void reduction,TaN intermediate layer,Elemental out-diffusion,Sputter-grown Cu2ZnSnS4
更新于2025-09-23 15:21:01
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CZTS solar cells and the possibility of increasing VOC using evaporated Al2O3 at the CZTS/CdS interface
摘要： We report the effect of an ultra-thin Al2O3 layer (down to 3 nm) as interface passivation strategy for the improvement of the performance of Cu2ZnSnS4/CdS based solar cells. After an initial optimization, the Al2O3 deposited by thermal evaporation is proved to improve the properties of the p-n junction. The fabricated devices showed an increment in Voc depending on the composition of the absorber, and an improvement in fill factor (FF) apparently related to the insulation of possible shunt-paths. Also, the impact on other optoelectronic parameters is discussed.
关键词： Al2O3,Interface passivation,Thermally evaporation,Cu2ZnSnS4 (CZTS)
更新于2025-09-23 15:19:57
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Enhanced photovoltaic performance and stability of perovskite solar cells by interface engineering with poly(4-vinylpyridine) and Cu2ZnSnS4&CNT
摘要： Organic-inorganic perovskite solar cells (PSCs) are emerging candidates for next generation photovoltaic devices. In the last decade, PSCs have depicted a rapid development in device performance, meanwhile, the issue of utilizing low-cost, non-toxic materials with chemical stability as well as long term device stabilities are still lacking. To address these issues, an inexpensive, eco-friendly, and environmentally stable nanostructure of the quaternary chalcogenide Cu2ZnSnS4 (CZTS) as an inorganic hole transport material (HTM) has been investigated. Moreover, simultaneously two strategies has been employed to optimize the photovoltaic parameters. First, an interlayer of poly(4-vinylpyridine) (PVP) has been applied between the perovskite and the hole transport layer (HTL). Second, single-walled carbon nanotubes (CNTs) is incorporated into the CZTS HTL. While, the latter only result in higher short circuit current density (Jsc) from 18.3 to 20 mA cm?2, by using both of the strategies an increase in open circuit voltage (Voc) from 0.98 to 1.05 V as well as Jsc from 18.3 to 20.5 mA cm?2 has been observed. The power conversion efficiency (PCE) of the record device reached to 15.2%, fill factor (FF) increased up to 70% and also demonstrated low hysteresis of 2.3%. The formation of hydrophobic CNT webs among the sphere-like CZTS nanostructures and the presence of the PVP polymeric interlayer results in highly stable devices, which retained more than 98% of the initial PCE at room temperature and 40–45% humidity after 30 days. Thus, our results show that the combination of PVP interlayer and CZTS&CNT HTL offer an opportunity for the scalability of PSCs.
关键词： Cu2ZnSnS4,Inorganic hole transport materials,Stability,Carbon nanotubes,Poly(4-vinylpyridine)
更新于2025-09-23 15:19:57
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Growth of Cu<sub>2</sub>ZnSnS<sub>4</sub> (CZTS) thin films using short sulfurization periods
摘要： In this study CZTS thin films were grown by a two-stage process that involved sequential sputter deposition of metallic Cu, Zn, and Sn layers on Mo coated glass substrates followed by RTP annealing at 530 and 560 °C for various dwell times (1, 60, and 180 sec). CZTS thin films obtained by reaction at different sulfurization temperatures and reaction times were characterized employing XRD, Raman spectroscopy, SEM, EDX, and photoluminescence. It showed that extension of the sulfurization time provides better crystalline quality except for the CZTS560-60 thin film. SEM surface microstructure of the films displayed non-uniform, dense, and polycrystalline structure. The optical band gap of the films as determined by photoluminescence was found to be about 1.36-1.38 eV. It was observed that it is possible to obtain Cu-poor and Zn-rich CZTS thin films with short dwell time of reactions. XRD pattern and Raman spectra of the films showed formation of kesterite CZTS structure and some secondary phases such as CuS, SnS, SnS2. The full-width-at-half-maximum (FWHM) values extracted from the (112) diffraction peaks of the CZTS thin films.
关键词： Sulfurization time,Cu2ZnSnS4 (CZTS),Two-stage method,Sputtering,Sulfurization temperature,Kesterite
更新于2025-09-19 17:15:36
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Sputtered ZnSnO buffer layers for kesterite solar cells
摘要： Replacing the CdS buffer layer with a ZnSnO one in Cu2ZnSnS4-based solar cells allows both to improve the device performances and to avoid using toxic Cd. Additionally, using a sputtered buffer layer is a major asset for solar cells fabricated by physical vapor deposition processes. In this study, ZnSnO layers are deposited by sputtering of a single metal-oxide target. Structural and optical properties of the layers deposited on Si or glass are first described. The possibility of modifying the ZnSnO metallic composition by adjusting the deposition power is demonstrated. Attempts to improve the optoelectronic properties of the ZnSnO layers with Ar:O2 or Ar:SF6 reactive sputtering are shown as well. These ZnSnO buffer layers are transferred in Mo/CZTS/ZnSnO/ZnO:Al solar cells. After post-deposition thermal treatment and optimization of the deposition condition (notably with the use of Ar:O2 or Ar:SF6 reactive sputtering), a solar cells with a power conversion efficiency of 5.2% is demonstrated. It is 0.6% absolute higher than the reference solar cell with a CdS buffer layer. To avoid absorber damaging and achieve high performances, deposition power must be as low as possible. A two stages sputtering process is used to conciliate both the absorber surface preservation and a reasonable deposition time. Last, photovoltaic properties of optimized CZTS- and CZTSe-based solar cells with ZnSnO buffer layers are compared.
关键词： Cu2ZnSnS4,ZnSnO buffer layer,Cd-free devices,sputtering,reactive sputtering,Kesterite solar cells
更新于2025-09-19 17:13:59
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Effect of Solvent on the Characteristic Properties of Nebulizer Spray Pyrolyzed Cu2ZnSnS4 Absorber Thin Films for Photovoltaic Application
摘要： Cu2ZnSnS4 (CZTS) thin films are the most promising absorber layer for thin film solar photovoltaics. The nebulizer assisted spray pyrolysis technique was employed to deposit the CZTS absorber thin films on bare soda lime glass substrate at a temperature of 350°C without annealing and sulfurization. Different solvents such as Dimethyl sulfoxide (DMSO), Ethylene diamine, 2-Methoxy ethanol and Water were used. The influence of these solvents on the structural, morphological, compositional, optical and electrical properties were studied using an X-ray diffractometer, Raman spectrometer, Scanning electron microscope annexed with energy dispersive X-ray spectrometer, Atomic force microscope, UV-vis spectrophotometer and a digital current source meter. The X-ray diffraction pattern reveals the formation of CZTS in all the solvents with preferential peak along [112] direction and the size of the crystallites is found to vary from 21 nm for DMSO to 34 nm for water. Raman analysis exhibited a phase pure film for all the solvents except the film prepared from DMSO which reveals a peak for the presence of Cu2S. The morphological and compositional analysis shows better texture with uniform coverage on the glass substrate and off stoichiometric ratio for all the deposited films. From the optical analysis it is seen that the prepared films show a broad absorption spectra in the visible region and the band gap was found to lie in the range of 1.15 eV to 1.51 eV. The current voltage characterization in dark shows significant increase in current with the applied voltage for all the films with DMSO film recording the lowest. Hall measurements revealed a carrier concentration of 1.93x1018 cm-3, mobility of 13.67 cm2/V s and a conductivity of 42.27 x10-2 ?-1 cm-1 for water. From this study, we infer that the CZTS film deposited using precursor solution derived from water exhibits phase purity along with enhanced photovoltaic properties at a substrate temperature of 350°C through nebulizer assisted spray pyrolysis technique.
关键词： Solar cell,Cu2ZnSnS4,Nebulizer assisted spray pyrolysis,Characterization,Thin film,Effect of solvent
更新于2025-09-19 17:13:59
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Effect of Na doping on the performance and the band alignment of CZTS/CdS thin film solar cell
摘要： Alkali doping can suppress deleterious antisite defects in kesterite Cu2ZnSnS4 (CZTS) and improve the open-circuit voltage. In this study, the effects of light Na-doping on the performance and the band alignment of CZTS/CdS thin-film solar cells were investigated. CZTS:Na thin films were fabricated by the spin coating with 10% Na doping on the surface of CZTS. The Na-doping led to the narrower FWHM and larger grain size. The hole concentration and the conductivity were improved due to the NaZn shallow acceptor defects. In addition, Na-doping can improve the band alignment of absorber/buffer interface and inhibit SRH recombination by the Na passivation effect and the suppression of SnZn defects. The typical cliff-like conduction band offset (CBO) was reduced from 0.25 eV in CZTS:Na/CdS to 0.1 eV in CZTS/CdS heterojunction. CZTS:Na device exhibited a higher Voc of 653 mV than that of CZTS/CdS device. The maximum conversion efficiency reached 7.46%, increased by 44% after Na-doping. These results clarify the effect of Na-doping on the band structure of the heterojunction in CZTS solar cells and support a new aspect that synthesis of a surface-doping CZTS:Na absorber has great potential for future research.
关键词： Conduction band offset,Na-doping,Cu2ZnSnS4,Band alignment,Cliff-like
更新于2025-09-19 17:13:59
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Facile designing and assessment of photovoltaic performance of hydrothermally grown kesterite Cu2ZnSnS4 thin films: Influence of deposition time
摘要： Herein, low cost precursor source Cu2ZnSnS4 (CZTS) nanocrystalline thin films at various reaction time were successfully synthesized via one step hydrothermal route. Hydrothermal route was employed to achieve control over the size and grain growth of CZTS films. As deposited CZTS films were analyzed for its optoelectronic, structural, morphological and electrochemical properties to investigate the effect of hydrothermal reaction time on growth and photovoltaic performance. The hydrothermal synthesis promoted to high absorption (104 cm?1) of the CZTS film with a decrease in optical band gap energy from 1.52 eV to 1.41 eV. Structural study revealed that, improved crystallinity with A1 mode of vibration for pure phase kesterite CZTS structure. Morphological transition was observed from nanograins to well grown and compact nanospheres. Compositional analysis illustrates, stoichiometric CZTS film formation with the desired valence state of Cu+, Zn2+, Sn4+ and S2? elements. Current density-voltage (J-V) measurement of FTO/CZTS/(0.3 M Eu3+/Eu2+)/Graphite cell configuration shows, highest photocurrent of 2.60 mA/cm2 and open circuit voltage of 754 mV was observed for CZTS4 sample with best photoconversion efficiency (η) 3.21% under illumination of 30 mW/cm2 light intensity. Electron impedance spectroscopy (EIS) showed that, generation of lower charge transfer resistance (Rct) with increase in reaction time.
关键词： Photoelectrochemical (PEC) cell,Cu2ZnSnS4 thin films,Electron impedance spectroscopy,Hydrothermal route
更新于2025-09-19 17:13:59
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Forming an Ultrathin SnS Layer on Cu <sub/>2</sub> ZnSnS <sub/>4</sub> Surface to Achieve Highly Efficient Solar Cells with Zn(O,S) Buffer
摘要： Environmental friendliness demands the use of nontoxic elements in all types of solar cells, and Zn(O,S) thin film as an alternative buffer layer to replace CdS layer in chalcopyrite and kesterite solar cells has attracted enormous attention in the past. However, Cu2ZnSnS4 (CZTS) solar cells with a Zn(O,S) buffer are far inferior to those with CdS buffer despite the potentially better band alignment. Herein, by intentionally controlling the precursor composition, the surface of CZTS can be modified to improve the quality of the Zn(O,S)/CZTS junction for the chemical bath-deposited Zn(O,S) buffer. Such a CZTS solar cell reaches a high conversion efficiency of 7.28%, the highest among all Zn(O,S)-based kesterite solar cells so far. The CZTS surface that can jointly work well with the Zn(O,S) buffer is further investigated using X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. The results indicate that an ultrathin SnS layer exists on the CZTS surface and effectively raises the conduction band edge of the absorber surface to form a conduction band offset barrier of (cid:3)0.40 eV, significantly better than that without the assistance of SnS layer. A key route for fabricating highly efficient and low-cost Cd-free CZTS thin-film solar cells is described.
关键词： band alignments,Zn(O,S) buffers,Cu2ZnSnS4
更新于2025-09-19 17:13:59
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Beyond 10% efficiency Cu <sub/>2</sub> ZnSnS <sub/>4</sub> solar cells enabled by modifying the heterojunction interface chemistry
摘要： Wide band gap pure sulphide kesterite Cu2ZnSnS4 is a promising environmentally friendly and low-cost photovoltaic material, which has attracted intense research interest. However, the record e?ciency of solar cells based on Cu2ZnSnS4 absorbers just overcame the benchmark 10%, being far from the e?ciency requirement for industrial-scale deployment. Recombination at the heterojunction interface accounts for a large proportion of the performance loss. Here we report a substantial improvement of the Cu2ZnSnS4 solar cell e?ciency to over 10% enabled by modifying the Cu2ZnSnS4/Zn1?xCdxS heterojunction interface. We found that the introduction of the ammonium hydroxide during the Zn1?xCdxS deposition process can lead to a signi?cant reduction of Zn related hydroxide and oxide impurities. The modi?ed chemistry environment at the heterojunction interface facilitates the decrease of interface defects and promotes the interface microstructure quality. The improved heterojunction interface with suppressed interface recombination contributes to the enhanced open circuit voltage, ?ll factor and overall device performance.
关键词： Cu2ZnSnS4,solar cells,Zn1?xCdxS,ammonium hydroxide,heterojunction interface
更新于2025-09-16 10:30:52