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Enhanced performance of tin halide perovskite solar cells by addition of hydrazine monohydrobromide
摘要： Although tin-based perovskite has been considered as a kind of potential environmentally-friendly photovoltaic materials, the tin-based perovskite solar cells are limited due to their poor stability and low conversion efficiency mainly tracing to the oxidation from Sn2t state in tin-based perovskite films. Herein, a facile reductive approach is developed to suppress the oxidation, in which tiny amount of hydrazine monohydrobromide is doped into FASnI3-based perovskite precursor solution as a reducing agent. Our results demonstrate that the addition of hydrazine monohydrobromide could reduce the defects and trap states in perovskite by inhibiting formation of tetravalent tin, and increase the open circuit voltage by widening the bandgap of perovskite. As a consequence, the best optimized perovskite solar cell achieves an excellent power conversion efficiency of 7.81%, which represented a 39.5% improvement compared to the best reference device. The optimized devices display stabilized power output near the maximum power point and negligible hysteresis effect.
关键词： Trap states,Defect,Hydrazine monohydrobromide,Lead-free,Tin-based perovskite solar cell
更新于2025-09-23 15:19:57
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Highly Reproducible and Efficient FASnI <sub/>3</sub> Perovskite Solar Cells Fabricated with Volatilizable Reducing Solvent
摘要： Lead-free tin halide perovskite solar cells (PSCs) have attracted great attention because of their low toxicity, ideal band gap, and high carrier mobilities. However, the efficiency and reproducibility of tin halide PSCs has been limited because of the facile oxidation of Sn2+ to Sn4+. Herein, liquid formic acid (LFA) was introduced as a reducing solvent in the FASnI3 (FA: formamidinium) perovskite precursor solution. Unlike solid reducing additives, the LFA solvent is volatile, so no residual LFA remained in the FASnI3 perovskite film. Use of the LFA solvent resulted in production of the FASnI3 perovskite film with high crystallinity, low Sn4+ content, reduced background doping, and low electronic trap density. As a result, an efficiency of over 10% was obtained for lead-free tin halide PSCs with improved reproducibility.
关键词： tin,Lead-free,oxidation,trap density,standard reduction potential
更新于2025-09-23 15:19:57
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Colloidal Synthesis and Charge-Carrier Dynamics of Cs2AgSb1-yBiyX6 (X: Br, Cl; 0 ≤y ≤ 1) Double Perovskite Nanocrystals
摘要： A series of lead-free double perovskite NCs: Cs2AgSb1-yBiyX6 (X: Br, Cl; 0≤y≤1) NCs are synthesized. In particular, Cs2AgSbBr6 NCs is a new double perovskite material that has not been reported for the bulk form. Mixed Ag-Sb/Bi NCs exhibit enhanced stability in colloidal solution compared to Ag-Bi or Ag-Sb NCs. Femtosecond transient absorption studies indicate the presence of two prominent fast trapping processes in the charge carrier relaxation. The two fast trapping processes are dominated by intrinsic self-trapping (1~2 ps) due to giant exciton-phonon coupling and surface defects trapping (50~100 ps), respectively. Slow hot-carrier relaxation is observed at high pump fluence, and the possible mechanisms for the slow hot-carrier relaxation are also discussed.
关键词： nanocrystal,double perovskite,carrier-phonon coupling,hot-carrier cooling,trap state
更新于2025-09-23 15:19:57
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Colloidal Synthesis and Charge-Carrier Dynamics of Cs2AgSb1-yBiyX6 (X: Br, Cl; 0 ≤y ≤ 1) Double Perovskite Nanocrystals
摘要： A series of lead-free double perovskite NCs: Cs2AgSb1-yBiyX6 (X: Br, Cl; 0≤y≤1) NCs are synthesized. In particular, Cs2AgSbBr6 NCs is a new double perovskite material that has not been reported for the bulk form. Mixed Ag-Sb/Bi NCs exhibit enhanced stability in colloidal solution compared to Ag-Bi or Ag-Sb NCs. Femtosecond transient absorption studies indicate the presence of two prominent fast trapping processes in the charge carrier relaxation. The two fast trapping processes are dominated by intrinsic self-trapping (1~2 ps) due to giant exciton-phonon coupling and surface defects trapping (50~100 ps), respectively. Slow hot-carrier relaxation is observed at high pump fluence, and the possible mechanisms for the slow hot-carrier relaxation are also discussed.
关键词： nanocrystal,double perovskite,carrier-phonon coupling,hot-carrier cooling,trap state
更新于2025-09-23 15:19:57
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On thermoluminescence mechanism and energy leakage in Lu2O3:Tb,V storage phosphor
摘要： The energy storage properties of Lu2O3:Tb,V sintered materials when exposed to X-rays were investigated for the first time using a number of thermoluminescent techniques. Thermoluminescence was generated exclusively by the Tb3+ ions, which served also as hole-trapping centers. Two TL peaks at ～170 °C and 220 °C were found to be directly connected with V-electron traps and were assigned to the release of first (170 °C) and second (220 °C) electron from VX Lu. It was evidenced that each of the two TL bands results from strongly overlapping components showing continuous distribution of energies. Significant contribution from semi-localized transitions to carriers annihilation was also proved.
关键词： Storage phosphors,Continuous distribution of trap energy,Lutetium oxide,Semi-localized transition model
更新于2025-09-19 17:15:36
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Luminescence and dielectric properties of Ni2+ ions added to calcio yttria borophosphate glasses for optoelectronic uses
摘要： Glass materials of composition CaO – Y2O3 – B2O3 – P2O5 added with different concentrations of NiO (Ni2+: CYBP) are synthesized by conventional rapid melt quenching method. Various physical properties of these glasses such as polaron radius (rp), molar volume (Vm), optical basicity (Λth) and refractive index (μ) are studied. As an elastic characterization Young’s modulus (Y), Poison ratio (σ) and micro hardness (H) of these glasses are studied. These grades suggest that the prepared materials are mechanically hard and exhibiting covalently interlinked structure. Further these samples are characterized by various techniques such as differential thermal analysis, thermoluminiscence, optical absorption, photoluminescence, Ionic conductivity and dielectric dispersion. The thermoluminiscence grades such as peak temperature maximum (Tm), shape symmetry factor (μsf) and activation energies ( Eτ, Eδ and Eω) are studied at various UV irradiation levels. These results strongly recommended that the both electron and hole trap centers were created at the deeper trap levels and contribute higher orders of thermoluminiscence emission with in these glasses subjected to higher orders of temperature and UV irradiation. The various optical absorption and photoluminescence factor's such as, optical band gap (Eo), nephelauxetic ratio (β), emission cross section (Ω), branching ratio (ζ) and radiative life times (τ) are studied. These grades found to be maximum for the material which has 0.5 mol% of NiO concentration may be most suggestible for optoelectronic application. The dc and ac conductivity (σdc & σac) of these glasses are estimated. The various dielectric parameter’s such as loss tangent (Tan (φ)), temperature region of relaxation (ΔT), density of states near Fermi level (N(Ef)), activation energies of both dipoles and conduction (Ed & Ec) are also calculated. These reports clearly disclose that the octahedrally located Ni2+ ions are increasing with increase NiO concentration with in present calcio yttria borophosphate glasses.
关键词： emission cross section,nephelauxetic ratio,micro hardness,trap depth parameters,Ni2+: CYBP glass materials,temperature region of relaxation
更新于2025-09-19 17:15:36
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Effect of maleic anhydride on trap levels of alumina/low-density polyethylene by photo-stimulated discharge
摘要： In this paper, the distribution of trap levels of alumina/low-density polyethylene (Al2O3/LDPE) modified by maleic anhydride (MAH) was studied by photo-stimulated discharge (PSD). The PSD results show that the energy level of charge traps in the 0.5% and 1% Al2O3/LDPE modified by MAH is mainly distributed in 4.68–5.64 eV, and the trap density maximum is at 235 nm and 230 nm, respectively. According to the experimental result, the maleic anhydride can provide pure polyethylene with abundant deep traps. However, it can effectively reduce trap density of the Al2O3/LDPE system, especially, this kind of mechanism of action is more obvious for the 1%-doped Al2O3/LDPE system.
关键词： maleic anhydride,Photo-stimulated discharge,trap levels,nanoparticles
更新于2025-09-19 17:15:36
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Gate Bias and Length Dependences of Total-Ionizing-Dose Effects in InGaAs FinFETs on Bulk Si
摘要： We evaluate the total-ionizing-dose (TID) responses of InGaAs nMOS FinFETs with different gate lengths irradiated with 10-keV X-rays under different gate biases. The largest degradation after irradiation occurs at VG = -1 V. Radiation-induced trapped positive charge dominates the TID response of InGaAs FinFET transistors, consistent with previous results for InGaAs multi-fin capacitors. Shorter gate-length devices show larger radiation-induced charge trapping than longer gate-length devices, most likely due to the electrostatic effects of trapped charge in the surrounding SiO2 isolation and SiO2/Si3N4 spacer oxides. 1/f noise measurements indicate a high trap density and a non-uniform defect-energy distribution, consistent with a strong variation of effective border-trap density with surface potential.
关键词： 1/f noise,FinFETs,InGaAs,Total-Ionizing-Dose,Bulk Si,border-trap,Gate length dependence,III-V
更新于2025-09-19 17:15:36
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Simultaneous photoreduction and Raman spectroscopy of red blood cells to investigate the effects of organophosphate exposure
摘要： Simultaneous photoreduction and Raman spectroscopy with 532 nm laser has been used to study the effects of organophosphate (chlorpyrifos) exposure on human red blood cells. Since in red blood cells, auto-oxidation causes oxidative stress, which, in turn, is balanced by the cellular detoxicants, any possible negative effect of chlorpyrifos on this balance should results in an increased level of damaged (permanently oxygenated) hemoglobin. Therefore, when 532 nm laser, at a suitable power, was applied to photoreduce the cells, only common oxygenated form of hemoglobin got photoreduced leaving the permanently oxygenated hemoglobin detectable in the Raman spectra simultaneously excited by the same laser. Using the technique effects of chlorpyrifos to build up oxidative stress on red blood cells could be detected at concentrations as low as 10 ppb from a comparison of relative strengths of different Raman bands. Experiments performed using simultaneously exposing the cells, along with chlorpyrifos, to H2O2 (oxidative agent) and/or 3-Aminotriazole (inhibitor of anti-oxidant catalase), suggested role of chlorpyrifos to suppress the cellular anti-oxidant mechanism. Since the high level of damaged hemoglobin produced by the action of chlorpyrifos (at concentrations > 100 ppm) is expected to cause membrane damage, atomic force microscopy was used to identify such damages.
关键词： atomic force microscopy,Photoreduction,optical trap,Raman spectroscopy,red blood cells,chlorpyrifos
更新于2025-09-19 17:15:36
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Electronic Traps and its Correlations to Perovskite Solar-Cell Performance via Compositional and Thermal-Annealing Controls
摘要： Herein, underlying factors for enabling efficient and stable performance of perovskite solar cells are studied through nanostructural controls of organic-inorganic halide perovskites. Namely, MAPbI3, (FA0.83MA0.17)Pb(I0.83Br0.17)3, and (Cs0.10FA0.75MA0.15)Pb(I0.85Br0.15)3 perovskites (abbreviated as MA, FAMA, and CsFAMA, respectively) are examined with a grain growth control through thermal annealing. FAMA- and CsFAMA- based cells result in stable photovoltaic performance while MA cells are sensitively dependent on the perovskite grain size dominated by annealing time. Micro-/nanoscopic features are comprehensively analysed to unravel the origin that is directly correlated to the cell performance with the applications of electronic-trap characterizations such as photoconductive noise microscopy and capacitance analyses. It is revealed that CsFAMA has a lower trap density compared to MA and FAMA through the analyses of 1/f noises and trapping/detrapping capacitances. Also, an open-circuit voltage (Voc) change is correlated to the variation of trap states during the shelf-life test: FAMA and CsFAMA cells with the negligible change of Voc over weeks exhibit trap states shifting toward the bandedge, although the power-conversion efficiencies are clearly reduced. It is discussed about the origins that critically affect the solar cell performance through the characterizations of shallow/deep traps with additional mobile defects in the perovskite and interfaces.
关键词： 1/f noise,Organic-inorganic halide perovskite,Perovskite solar cell,Capacitance,Electronic trap
更新于2025-09-19 17:15:36