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Development of a Mixed Halide-chalcogenide Bismuth-based Perovskite MABiI <sub/>2</sub> S with Small Bandgap and Wide Absorption Range
摘要： During the last years, the lead perovskites have achieved high power conversion efficiency of 23%. However, its long-term stability and toxicity are still the crucial issues that required attention. In this study, we are the first to report on the synthesis and characterizations of a new lead-free mixed halide-chalcogenide perovskite MABiI2S (MBIS), and determined its physical and optical properties by various testing methods. The MBIS has a low bandgap of 1.52 eV, with an extended absorption onset up to over 1000 nm. Solar cells fabricated with the MBIS were inspected and device improvement were applied.
关键词： Bismuth-based perovskite,Small bandgap,Lead free perovskites
更新于2025-09-23 15:23:52
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A Guide to Small-Scale Energy Harvesting Techniques || Quest for Lead-Free Perovskite-Based Solar Cells
摘要： Today, the perovskite solar cells (PSCs) are showing excellent potentials in terms of simple processing, abundance of materials, and architectural integration, as well as very promising device’s power conversion efficiencies (PCEs), rocketed from 3.8% in 2009 to 23.3% in 2018. However, the toxic lead (Pb) element containing the chemical composition of typically used organic-inorganic halide perovskites hinders the practical applications of PSCs. This chapter starts with a general discussion on the perovskite crystal structure along with the serious efforts focused on Pb replacement in these devices. Section 2 will elaborate the fundamental features of tin (Sn)-based perovskites together with their performance in the PSCs. Other alternative elements, such as copper (Cu), germanium (Ge), bismuth (Bi), and antimony (Sb), will be discussed in Section 3. The end will summarize the challenges and opportunities based on the chapter contents.
关键词： stability,lead-free perovskites,chemical composition,toxicity
更新于2025-09-23 15:21:01
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Lead-free perovskite/organic semiconductor vertical heterojunction for highly sensitive photodetectors
摘要： In recent years, photodetectors based on organic-inorganic lead halide perovskites have been studied extensively. However, the inclusion of lead in those materials can cause severe human health and environmental problems, which is undesirable for practical applications. Here, we report high-performance photodetectors with a tin-based perovskite/PEDOT:PSS vertical heterojunction. The device demonstrates broadband photo-response from NIR to UV. The maximum responsivity and gain are up to 2.6 × 106 A/W and 4.7 × 106, respectively. Moreover, a much shorter response time and higher detectivity can be achieved by reducing the thickness of PEDOT:PSS. The outstanding performance is due to the excellent optoelectronic properties of the perovskite and the photo-gating effect originated from the heterojunction. Furthermore, devices fabricated on flexible substrates can demonstrate not only high sensitivity but also excellent bending stability. This work opens up the opportunity of using lead-free perovskite in highly sensitive photodetectors with vertical heterojunctions.
关键词： Photo-gating,heterojunction,organic semiconductors,Photodetectors,Lead free perovskites
更新于2025-09-23 15:21:01
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Laser-Induced Optoelectronic and Crystallographic Tuning of Methyl Ammonium Iodobismuthate Perovskite for Improved Performance of Sandwiched a?? Type Photodetectors
摘要： Towards development of high-performance perovskite based photodetectors, it is required that optical and crystallographic properties of perovskites materials be enhanced through perovskites materials modification. Many attempts on this quest result in alteration of chemical structure of perovskites materials through introduction of dopants. Here in, we present a clean and structural preservative technique of tuning optical and crystallographic properties of bismuth based lead free perovskite materials through irradiation with 2.5 mJ laser pulses ejected from Nd:YAG LASER operating in its second harmonics. XRD spectra show improved crystallinity and reduced crystallite size, SEM images show defect – minimized surface morphology, PL spectra show minimized rate of Auger recombination and absorbance spectra show improved absorbance at a constant band gap value. Consequently, simplified sandwiched architectural type photodetectors fabricated with the modified bismuth based perovskite materials display maximum photodetectivity of 4.5 × 109 Jones, maximum photoresponsivity of 25 μA/W, maximum photosensitivity of about 104 and minimum optical switching times of 10 ms under testing conditions of -2 V bias voltage, 15 mW/cm2 incident solar light and room temperature. Thus, laser pulses irradiation presents an alternative method of enhancing optical and crystallographic properties of perovskite materials from which highly efficient classes of photonics and photovoltaic devices can be developed.
关键词： Laser Irradiation,crystallographic properties,optical properties,perovskite photodetectors,lead free perovskites materials
更新于2025-09-23 15:21:01
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Inorganic Halide Perovskite Solar Cells: Progress and Challenges
摘要： All-inorganic perovskite semiconductors have recently drawn increasing attention owing to their outstanding thermal stability. Although all-inorganic perovskite solar cells (PSCs) have achieved significant progress in recent years, they still fall behind their prototype organic–inorganic counterparts owing to severe energy losses. Therefore, there is considerable interest in further improving the performance of all-inorganic PSCs by synergic optimization of perovskite films and device interfaces. This review article provides an overview of recent progress in inorganic PSCs in terms of lead-based and lead-free composition. The physical properties of all-inorganic perovskite semiconductors as well as the hole/electron transporting materials are discussed to unveil the important role of composition engineering and interface modification. Finally, a discussion of the prospects and challenges for all-inorganic PSCs in the near future is presented.
关键词： perovskites,inorganic perovskite,lead-based,perovskite solar cells,lead-free perovskites
更新于2025-09-23 15:19:57
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Ion Exchange/Insertion Reactions for Fabrication of Efficient Methylammonium Tin Iodide Perovskite Solar Cells
摘要： The low toxicity, narrow bandgaps, and high charge-carrier mobilities make tin perovskites the most promising light absorbers for low-cost perovskite solar cells (PSCs). However, the development of the Sn-based PSCs is seriously hampered by the critical issues of poor stability and low power conversion efficiency (PCE) due to the facile oxidation of Sn2+ to Sn4+ and poor film formability of the perovskite films. Herein, a synthetic strategy is developed for the fabrication of methylammonium tin iodide (MASnI3) film via ion exchange/insertion reactions between solid-state SnF2 and gaseous methylammonium iodide. In this way, the nucleation and crystallization of MASnI3 can be well controlled, and a highly uniform pinhole-free MASnI3 perovskite film is obtained. More importantly, the detrimental oxidation can be effectively suppressed in the resulting MASnI3 film due to the presence of a large amount of remaining SnF2. This high-quality perovskite film enables the realization of a PCE of 7.78%, which is among the highest values reported for the MASnI3-based solar cells. Moreover, the MASnI3 solar cells exhibit high reproducibility and good stability. This method provides new opportunities for the fabrication of low-cost and lead-free tin-based halide perovskite solar cells.
关键词： ion exchange/insertion reaction,solar cells,crystal growth,lead-free perovskites
更新于2025-09-23 15:19:57
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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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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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First-Principles Screening of Lead-Free Mixed-Anion Perovskites for Photovoltaics
摘要： Organic-inorganic hybrid lead perovskites have made rapid progress in photovoltaic fields. However, the toxicity and poor long-term stability of these materials still limit their further commercial application. Herein, we proposed a system of lead-free mixed-anion perovskites in which a chalcogen element is incorporated into the perovskite octahedrons to improve the system stability. We performed first-principles calculations of the bandgaps of 192 lead-free mixed-anion perovskites belonging to the class of ABX'X"2, where A=Cs+, CH3NH3+, and HC(NH2)2+; B=Ga3+, In3+, Sb3+, Bi3+; X'= O2-, S2-, Se2-, and Te2-, and X"= F-, Cl-, Br-, and I-. The bandgap shows a linear relationship with the average anion electronegativity. The contribution of anions to the band edge states is related to electron affinity and structure parameters. Considering multiple factors forming perovskites, we screened out a promising candidate, CsInOBr2, with a suitable bandgap (1.3 eV) for application in photovoltaics.
关键词： theoretical screening,GLLB-SC methods,photovoltaic materials,lead-free perovskites,bandgap
更新于2025-09-12 10:27:22
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Broadband Defects Emission and Enhanced Ligand Raman Scattering in 0D Cs <sub/>3</sub> Bi <sub/>2</sub> I <sub/>9</sub> Colloidal Nanocrystals
摘要： Excitonic 0D and 2D lead-halide perovskites have been recently developed and investigated as new materials for light generation. Here broadband (>1 eV) emission from newly synthesized 0D lead-free colloidal Cs3Bi2I9 nanocrystals (NCs) is reported. The nature of their emissive states as well as the relative dynamics which are currently hotly debated are investigated. In particular, it is found that the broadband emission is made by the coexistence of emissive excitons and sub-bandgap emissive trap-states. Remarkably, evidence of enhanced Raman scattering from the ligands is observed when attached to the NCs surface, an effect that is preliminarily attributed to strong exciton-ligands electronic coupling in these systems.
关键词： trap-states emission,enhanced Raman scattering,broadband emission,lead-free perovskites,0D nanocrystals
更新于2025-09-10 09:29:36