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Solution-processed one-dimensional CsCu <sub/>2</sub> I <sub/>3</sub> nanowires for polarization-sensitive and flexible ultraviolet photodetectors
摘要： Polarization-sensitive ultraviolet (UV) photodetectors are highly desired due to their great significance in many applications. As the newly-emerging functional semiconductors, the metal-halide perovskites have attracted huge attention in photodetection due to their excellent optoelectronic features. However, the ever-reported perovskites polarized photodetectors mainly focused on the visible/infrared-light region, and the devices targeted at the UV region have not been reported. Here, for the first time, ternary copper halides CsCu2I3 nanowire was used as the light absorber to achieve polarization-sensitive UV photodetection. By combining the intrinsic anisotropy of the asymmetry structure and external morphology anisotropy of CsCu2I3 nanowires, a record photocurrent anisotropy ratio of ~3.16 was achieved, and also the shortcomings of lead-toxicity and environmental instability for conventional lead-halide perovskites were overcome effectively. Moreover, such photodetectors fabricated on flexible substrate demonstrate good flexibility and stability, showing almost no photoresponse degradation after extremely bending for 1000 cycles. The results suggest that the lead-free CsCu2I3 nanowire is potentially an attractive candidate for high-performance polarization-sensitive UV photodetectors compatible for practical applications.
关键词： CsCu2I3 nanowires,Polarization-sensitive,metal-halide perovskites,lead-free,ultraviolet photodetectors,flexible substrate
更新于2025-09-19 17:13:59
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Perovskite Solar Cells: Can We Go Organic‐Free, Lead‐Free, and Dopant‐Free?
摘要： Having demonstrated incredibly fast progress in power conversion efficiency, rising to a level comparable with that of crystalline silicon cells, lead-based organic–inorganic hybrid perovskite solar cells are now facing the stability tests needed for industrialization. Poor thermal stability (<150 °C) owing to organic constituents and interlayer diffusion of materials (dopants), and environmental incompatibility due to Pb has surged the development of organic-free, Pb-free perovskites and dopant-free hole transport materials (HTMs). The recent rapid increase in efficiency of cells based on inorganic perovskites, crossing 18%, demonstrates the great potential of inorganic perovskites as thermally stable and high-efficiency cells. Although all kinds of Pb-free perovskites lag in efficiency in comparison to the hybrid and inorganic perovskites, they also demonstrate better structural and environmental stability. The performance of dopant-free HTMs matching/surpassing dopant-containing HTMs makes the former a better choice for stability. Even though the efforts to enhance the stability of Pb-based hybrid perovskites should continue by different techniques, organic-free and lead-free perovskites, and dopant-free HTMs must be pursued with greater interest for the future. This review describes the present issues and possible strategies to address them, and thus will help to improve the overall performance of robust organic-free, Pb-free, and dopant-free perovskite solar cells.
关键词： solar cells,lead free,photovoltaics,perovskites,all inorganic
更新于2025-09-19 17:13:59
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Chalcogenide Materials and Derivatives for Photovoltaic Applications
摘要： Chalcogenide AB(S,Se)3 materials have recently attracted increased attention as they could simultaneously solve both the stability and toxicity issues faced by conventional perovskite solar cells. Computer-aided design of metal chalcogenide semiconductors has experienced important progress over the past few years, leading to the discovery of very promising AB(S,Se)3 compounds and derivatives for application as absorbers in thin-film photovoltaic devices. Experimental evidence demonstrates that the synthesis of such compounds is possible, confirming the theoretical predictions, although more research work needs to be done to further investigate the optoelectrical properties of the corresponding thin films. With the aim to provide an exhaustive starting point to further develop chalcogenide absorbers and related devices, this Review presents both an overview of the predicted chalcogenide materials and interesting derivatives for thin-film solar cells applications, as well as a summary of the synthesis techniques developed so far to prepare such materials. The possible challenges that can be encountered during the development of chalcogenide-based solar cells are also discussed.
关键词： lead-free perovskites,chalcogenides,solar cells,computational materials designs,thermodynamic stabilities
更新于2025-09-19 17:13:59
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Numerical modeling of lead-free perovskite solar cell using inorganic charge transport materials
摘要： Ten years after their first mention in report on solar cell implementation, organic-inorganic hybrid perovskites are still the focal point of photovoltaic research. Proper selection of material for different layers has enabled high power conversion efficiency (PCE) values that presently surpass 24%. Unfortunately, the metal halide perovskite solar cells (PSC) contain toxic lead, which is a serious concern for their commercialization process. To tackle lead toxicity issues in perovskite-based solar cells, intensive research by PSC research fraternity is ongoing to develop lead-free metal halide perovskite. In this paper, a novel solar cell configuration which consists of FTO/Transition Metal Di-Chalcogenides/Perovskite/Copper thiocyanate/Au is proposed. In this Transition Metal Di-Chalcogenides (Tungsten Disulfide) is used as an electron transport metal (ETM) due to its high electron mobility and Copper thiocyanate (CuSCN) is used as a hole transport metal (HTM) due to its high transparency and ideal band alignment with perovskite. Impact of variation in thickness of perovskite layer, electron transport layer and hole transport layer on performance parameters were examined. A PCE of 19.84% is achieved at the optimal perovskite layer thickness of 700 nm. When the thickness surpasses 700 nm, PCE drops due to an increase in the recombination of electron-hole pairs. Impact of interfacial defects on the performance parameter was also scrutinized. Simulation results reveal that the interfacial defect of ETM/Perovskite has a larger impact on performance parameters than that of Perovskite/HTM defect when light is irradiated from the ETM side. We also investigated the effect of temperature variation on device performance. The PSC showed optimum performance in the range of 20 °C to 50 °C and the ideal working temperature was viewed as 30 °C.
关键词： Transition metal di-chalcogenides,Power conversion efficiency,Stability,Lead-free perovskite,Copper thiocyanate
更新于2025-09-19 17:13:59
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Chinaa??s progress of perovskite solar cells in 2019
摘要： Perovskite solar cells (PSCs) have attracted worldwide attention due to their high efficiency and low manufacturing cost. As the largest supplier of photovoltaic modules, China has made huge endeavors in the research on PSCs. In 2019, Chinese research groups were still holding the top position for paper publications in the world. Both the efficiency and the stability of the device have been steadily increasing, pushing forward the commercialization of PSCs step by step. This review summarizes the highlights of China’s PSC research progress in 2019 and briefly introduces the development of PSC modules in industry.
关键词： Module,Stability,Perovskite solar cells,Lead-free
更新于2025-09-19 17:13:59
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Effect of mixed halide contents on structural, electronic, optical and elastic properties of CsSnI <sub/>3a??x</sub> Br <sub/>x</sub> for solar cell applications: first-principles study
摘要： In this study, structural, electronic, optical and elastic properties of CsSnI3?xBrx perovskites are investigated by full potential linearized augmented plane wave method (FP-LAPW) with exchange correlation functionals GGA-PBE and GGA-mBJ as implemented in Wien2k. The calculated structural parameters for all compositions are in good correlation with literature. The band structures and density of states (DOS) are calculated by GGA which indicated that all these alloys have direct band gap. Furthermore, the band gaps are also calculated by employing modified Beck-Johnson’s (mBJ) exchange potential. The obtained band gaps with this method are found to be improved as compared to GGA. The calculated optical parameters show that these materials have the competency for light absorption and to retain it. These characteristics make them promising materials for solar cell applications. The elastic constants have also been calculated which revealed that all these compounds have ductile nature. The mixed halide contents are pioneered in this study and therefore, no data is in hand for estimation.
关键词： optical and elastic properties,electronic properties,lead free perovskites,halide contents,modified beck and johnson (mbj) exchange potential
更新于2025-09-16 10:30:52
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Ferroelectric ordering and energy storage capacity in lead-free Ba(Zr <sub/>0.2</sub> Ti <sub/>0.8</sub> )O <sub/>3</sub> nanoscale film capacitors fabricated using pulsed laser deposition technique
摘要： Dielectric thin film capacitors, storing large charge density, are useful in electric energy storing devices. Highly oriented lead-free BaZr0.20Ti0.80O3 (BZT20) thin films were grown on a conducting bottom layer La0.7Sr0.3MnO3 deposited on a MgO (100) substrate under an oxygen atmosphere using a pulsed laser deposition technique. X-ray diffraction studies indicate that BZT20 films were stabilized in a (100) oriented tetragonal phase. Microstructural studies on thin films indicate a smooth film (a roughness of ～1.25 nm) with a thickness of around 320 nm. The structural sensitive A1(TO2) Raman band exhibits a discontinuous change across the tetragonal-cubic phase transition temperature Tc ～ 275 K. The appearance of the broad Raman band in the cubic (Pm?3m) phase at an elevated temperature suggests the activation of symmetry forbidden Raman active bands. The temperature dependent band frequency and integrated intensity of the structural sensitive A1(TO2) band show anomaly across Tc. Temperature dependent dielectric studies (100–650 K) carried out in a wide range of frequencies 102–106 Hz on a fabricated Pt/BZT20/LSMO metal-insulator-metal capacitor suggest a broad dispersive peak of around 290 K. The polarization relaxation follows the Vogel-Fulcher relation with an activation energy of Ea = 0.047 eV and a freezing temperature of Tf = 246 K. The slim polarization P-E loops with a remanent polarization of ～89.6 μC/cm2 and an EC value of ～0.29 MV/cm were observed, suggesting its local ferroelectric ordering in corroboration with Raman and dielectric findings. From the P-E loop analysis, a large energy storage density of 31.9 J/cm3 and an energy storage efficiency of 56% were obtained. Our experimental results revealed that the BZT20 thin film capacitors have potential for energy storage device applications.
关键词： Ferroelectric ordering,Ba(Zr0.2Ti0.8)O3,energy storage capacity,nanoscale film capacitors,lead-free,pulsed laser deposition technique
更新于2025-09-16 10:30:52
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Electrospun Lead-Free All-Inorganic Double Perovskite Nanofibers for Photovoltaic and Optoelectronic Applications
摘要： Organic-inorganic hybrid perovskite compounds are currently the archetypal materials for high performance photovoltaic (PV) and optoelectronic devices. However, the remaining bottle necks preventing their large scale production are their environmental/thermal instability and lead toxicity. Herein, we demonstrate a novel approach to synthesize single phase electrospun Cs2SnIxCl6-x double perovskites with varying halide content (I, Cl or mixed I/Cl) as active materials for potential application in perovskite solar cells (PSCs). The x-ray photoelectron spectroscopy and Raman spectroscopy analyses indicated the in-situ formation of graphene oxide (GO) during the annealing process. The GO layer was found to enhance the optical properties and thermal stability of the fabricated perovskites even at high Cl content. Moreover, the presence of GO as an insulating layer significantly decreases the band gap energy of the resulting perovskites. The perovskites with a mix iodide and chloride ions showed significantly improved optical properties with higher photoluminescence (PL) intensity than that of pure chloride or iodide counterparts. Moreover, the compound with low chloride content showed superior thermal stability to those reported in literature. Therefore, the application of the electrospinning technique is a useful strategy to in-situ incorporate GO in lead-free perovskite matrix for potential photovoltaic and optoelectronic applications.
关键词： DFT,perovskite,stability,graphene,optics,lead-free
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing INTERNATIONAL SYMPOSIUM ON GREEN AND SUSTAINABLE TECHNOLOGY (ISGST2019) - Perak, Malaysia (23–26 April 2019)] INTERNATIONAL SYMPOSIUM ON GREEN AND SUSTAINABLE TECHNOLOGY (ISGST2019) - Lead-free solders for ribbon interconnection of crystalline silicon PERC solar cells with infrared soldering
摘要： We report about the analysis of Pb-free, low-temperature solders for the ribbon-interconnection of PERC solar cells with an industrial infrared stringer. Five solders (SnPb, SnBi-A, SnBi-B, SnBiAg and a proprietary lead-free, low-temperature (PLFLT) alloy) are characterized with di?erential scanning calorimetry to determine the melting and solidi?cation temperature. It is found that SnBi-B, SnBiAg, and the PLFLT composition melt in a temperature range between 137 ?C to 171 ?C instead of a single temperature. Solidi?cation occurs at a 3 K to 11 K lower temperature (undercooling). Mono-crystalline silicon PERC cells are contacted using an industrial stringer. The microstructure of the solder bonds is investigated with scanning electron microscopy. For the SnBi-A-solder, large and brittle Bi-phases are identi?ed. The SnBi-B, SnBiAg and PLFLT solder show a ?ner grain structure. The added Ag in SnBiAg forms an intermetallic compound of Ag3Sn close to the Cu-core of the ribbon. The peel strength of the connected solar cells with the Pb-free solders is on average 1 N mm?1 or slightly higher. Some bonds show low adhesion. The observed fracture mode is mainly failure at the busbar metallization to solar cell irrespective of the solder type. However, the occasionally observed solder residues on the metallization clearly reveal brittle fracture for the Pb-free solders, which is not observed for SnPb. First reliability tests show similar degradation of 1 % to 2 % for all solders.
关键词： ribbon interconnection,infrared soldering,lead-free solders,crystalline silicon PERC solar cells
更新于2025-09-16 10:30:52
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Charge Injection from Excited Cs2AgBiBr6 Quantum Dots into Semiconductor Oxides
摘要： Lead-free double perovskites such as Cs2AgBiBr6 are gaining attention because of their environmental friendliness compared to the lead halide perovskites. In order to establish their photoactivity, we have probed the excited state behavior of Cs2AgBiBr6 nanocrystals and charge injection from their excited state into different metal oxides (TiO2, ZnO). The electron transfer rate constants determined from ultrafast transient absorption spectroscopy were in the range of 1.2–5.2 × 1010 s-1. Under steady state photolysis (ambient conditions) the electrons injected into TiO2 are scavenged by atmospheric oxygen, leaving behind holes which accumulate within the quantum dots (QDs). These accumulated holes further induce oxidation of QDs, resulting in the overall photodegradation of perovskite film. Annealed films of Cs2AgBiBr6 nanocrystals, when employed as an active layer in solar cell, delivered photocurrent under visible light excitation.
关键词： Metal oxides,Quantum dots,Photodegradation,Charge injection,Cs2AgBiBr6,Solar cells,Lead-free double perovskites
更新于2025-09-12 10:27:22