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Radiation effects on the performance of flexible perovskite solar cells for space applications
摘要： Solar cells for space applications are required to be tolerant to harsh environmental conditions. Especially, tolerance against radiation and charged particles is mandatory. Here we study the effect of low-energy (<< 1 MeV) proton radiation to evaluate the radiation tolerance of flexible perovskite solar cells (PSCs). Low-energy protons are more likely to be stopped in the shallower regions of solar cells, thereby causing greater performance degradation than high-energy protons. Flexible PSCs with layer sequence PET/ITO/PEDOT:PSS/perovskite/PCBM/BCP/metal were fabricated and were irradiated with 100 keV protons (fluence from ~ 3 × 1010 to ~ 3 × 1012 protons/cm2, equating several years in space). Flexible PSCs exhibited a good radiation tolerance and did not show color center formation, revealing their outstanding resistance against low-energy proton radiation. This can be credited to the combined effect of intrinsically large carrier diffusion length exceeding the thin absorber film thickness and the defect tolerance of perovskite crystals.
关键词： defect tolerance,space applications,radiation tolerance,low-energy proton radiation,flexible perovskite solar cells
更新于2025-09-23 15:19:57
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The effect of manufacturing defects on the fatigue life of selective laser melted Ti-6Al-4V structures
摘要： The manufacturing defects introduced by selective laser melting typically lead to lower fatigue strength and a larger variation in fatigue life compared to conventionally manufactured structures. X-ray micro computed tomography (μCT) is used to characterize the porosity and lack of fusion defects in terms of population, morphology, dimension and location. The defect size and location are combined with the NASA/FLACGRO (NASGRO) fatigue crack growth model to predict the likely fatigue life, in which an effective initial crack length is defined using the cyclic plastic zone and the defect radius. An eXtended defect zone (XDZ) describing the propensity for local plasticity during fatigue around a defect has been shown through numerical analysis to be a good indicator of the ranking of the threat to fatigue caused by differently located manufacturing defects. This indicates that the effect of a defect, initial radius, r0, is likely to be pronounced when its center is within 2r0 of the surface and maximal when it lies just beneath the surface.
关键词： Additive manufacturing,High cycle fatigue (HCF),Fatigue crack initiation and growth,Digital printing,Defect tolerance method
更新于2025-09-23 15:19:57
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Bournonite CuPbSbS3: an electronically-3D, defect-tolerant, and solution-processable semiconductor for efficient solar cells
摘要： The absorber layer is a key component of thin-film solar cells. Based-on the recently-proposed electronic dimensionality concept, a promising solar cell absorber material should be electronically high-dimensional, as is the case for all the mainstream absorbers, such as Si, GaAs, CIGS, CdTe, and CH3NH3PbI3. In this work, we propose an electronically three-dimensional semiconductor, bournonite CuPbSbS3, as a prospective efficient solar cell absorber material. Our density functional theory calculations indicate that CuPbSbS3 exhibits desired optoelectronic properties, such as a nearly direct bandgap, high optical absorption coefficients, appropriate p-type doping, and defect tolerance. Experimentally, we developed a butyldithiocarbamate acid (BDCA) solution process for depositing high-quality CuPbSbS3 thin films and built the first CuPbSbS3 solar cells. Our CuPbSbS3-based thin film solar cells achieved a preliminary power conversion efficiency of 2.23% (open circuit voltage of 699 mV), highlighting the potential of this semiconductor for thin film photovoltaics.
关键词： defect tolerance,thin film solar cell,BDCA solution,Bournonite,electronic dimensionality
更新于2025-09-19 17:13:59
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A new approach to correlate the defect population with the fatigue life of selective laser melted Ti-6Al-4V alloy
摘要： Microstructural features and defects arising from selective laser melting (SLM) determine the in-service performance of additively manufactured near-net-shape components. Here the grain type, shape, size and distribution were characterized using electron backscattered diffraction (EBSD). High-resolution synchrotron radiation X-ray computed tomography was used to quantify the population, morphology and dimensions of porosity and lack of fusion defects. For SLM Ti-6Al-4V alloy, the larger-sized defects in comparison with α′ grains are more important for crack initiation, typically leading to poor fatigue resistance and a pronounced variation in fatigue life. The fatigue strength was then evaluated in terms of the defect population using a combination of the statistics of extremes and the Murakami model. Finally, an extended Kitagawa-Takahashi fatigue diagram was established within the framework of defect-tolerant design, which includes a classical safe-life region and the defect-determined lifetime in the finite life region.
关键词： Defect tolerance assessment,Chapetti model,Fatigue crack initiation and propagation,Kitagawa-Takahashi diagram,Additive manufacturing
更新于2025-09-19 17:13:59
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Effects of laser peening on the fatigue strength and defect tolerance of aluminum alloy
摘要： The effects of laser peening (LP) on the bending fatigue strength of the 7075-T651 aluminum alloy were investigated. Accordingly, the defect tolerance of the aluminum alloy subjected to LP is discussed on the basis of fracture mechanics. The results indicate that a deeper compressive residual stress was induced by LP compared with the case of shot peening (SP). The fatigue strengths increased when both peening types were used. Semicircular slits with depths less than 0.4 and 0.1 mm were rendered harmless on the basis of the applications of LP and SP, respectively. The apparent threshold stress intensity factor range ΔKth,ap increased by approximately five and two times owing to LP and SP, respectively. The increase of the ΔKth,ap was caused by the compressive residual stress induced by the peening. The Kitagawa-Takahashi diagram of the laser-peened specimens shows that the defect tolerance of the aluminum alloy was improved by LP.
关键词： fatigue strength,laser peening,residual stress,shot peening,defect tolerance,aluminum alloy
更新于2025-09-16 10:30:52