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Ambient-Processed, Additive-Assisted CsPbBr3 Perovskite Light-Emitting Diodes with Colloidal NiOx Nanoparticles for Efficient Hole Transporting
摘要： In this study, the electrically driven perovskite light-emitting diodes (PeLEDs) were investigated by hybridizing the organic polyethylene oxide, 1,3,5-tris (N-phenylbenzimiazole-2-yl) benzene (TPBi), and bis(3,5-di?uoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (FIrpic) with CsPbBr3 in the emission layer and adopting the colloidal NiOx nanoparticle (NP) hole transport layer. The synthesized NiOx NPs, having an average size of ~5 nm, can be spin-coated to become a smooth and close-packed ?lm on the indium–tin–oxide anode. The NiOx NP layer possesses an overall transmittance of ~80% at 520 nm, which is about the peak position of electroluminescence (EL) spectra of CsPbBr3 emission layer. The coating procedures of NiOx NP and CsPbBr3 layers were carried out in ambient air. The novel PeLED turned on at 2.4 V and emitted bright EL of 4456 cd/m2 at 7 V, indicating the remarkable nonradiative-related defect elimination by organic additive addition and signi?cant charge balance achieved by the NiOx NP layer.
关键词： colloidal NiOx nanoparticles,organic additives,ambient-process,perovskite light-emitting diodes (PeLEDs),inorganic lead halide perovskites
更新于2025-09-23 15:19:57
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Inorganic halide double perovskites with optoelectronic properties modulated by sublattice mixing
摘要： All-inorganic halide double perovskites have emerged as a promising class of materials that are potentially more stable and less toxic than lead-containing hybrid organic-inorganic perovskite optoelectronic materials. In this work, 311 cesium chloride double perovskites (Cs2BB’Cl6) were selected from a set of 903 compounds as likely being stable based on a statistically learned tolerance factor (t) for perovskite stability. First-principles calculations on these 311 double perovskites were then performed to assess their stability and identify candidates with band gaps appropriate for optoelectronic applications. We predict that 261 of the 311 Cs2BB’Cl6 compounds are likely synthesizable based on a thermodynamic analysis of their decomposition to competing compounds (decomposition enthalpy < 0.05 eV/atom). Of these 261 likely synthesizable compounds, 47 contain no toxic elements and have direct or nearly direct (within 100 meV) band gaps between 1 and 3 eV as computed with hybrid density functional theory (HSE06). Within this set, we identify the triple alkali perovskites Cs2[Alk]+[TM]3+Cl6, where Alk is a group 1 alkali cation and TM is a transition metal cation, as a class of Cs2BB’Cl6 double perovskites with remarkable optical properties, including large and tunable exciton binding energies as computed by the GW-Bethe Salpeter Equation (GW-BSE) method. We attribute the unusual electronic structure of these compounds to the mixing of the Alk-Cl and TM-Cl sublattices, leading to materials with small band gaps, large exciton binding energies, and absorption spectra that are strongly influenced by the identity of the transition metal. The role of the double perovskite structure in enabling these unique properties is probed through analysis of the electronic structures and chemical bonding of these compounds as compared with other transition metal and alkali transition metal halides.
关键词： stability,sublattice mixing,band gaps,inorganic halide double perovskites,optoelectronic properties,excitons
更新于2025-09-23 15:19:57
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Nanoscale Perovskite-Sensitized Solar Cell Revisited: Is This Dye-Cell or Perovskite-Cell?
摘要： A general and straightforward way of preparing few nanometer-sized well-separated MAPbIxBr3-x perovskite photosensitizers on the surface of ~1 μm thick mesoporous TiO2 photoanode was suggested via a two-step sequential deposition of low-concentrated lead halides (0.10 ~ 0.30 M PbI2 or PbBr2) and methylammonium iodide/bromide (MAI/MABr). When those nanoscale MAPbIxBr3-x perovskites are incorporated as a photosensitizer in typical solid state dye-sensitized solar cells (ss-DSSCs), it could be verified clearly by the capacitance analysis that nano-particulate MAPbI3 perovskites are playing the same role as that of a typical dye sensitizer (MK-2 molecule) though their size, composition and structure are different.
关键词： perovskites,Impedance analysis,solid state dye-sensitized solar cells,sensitizers,nanostructures
更新于2025-09-23 15:19:57
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Asymmetric Alkyl Diamine Based Dion-Jacobson Low-Dimensional Perovskite Solar Cells with Efficiency Exceeding 15%
摘要： Low-dimensional (LD) Dion-Jacobson perovskites (DJPs) are showing great potential to solve the stability issue of perovskite solar cells (PSCs). However, it is still a challenge to simultaneously obtain high power conversion efficiency (PCE) and high stability in DJP-LD-PSCs. Here, we present an asymmetric alkyl diammonium 3-(dimethylammonium)-1-propylammonium (DMAPA2+) as spacer cation to resolve this issue. With small adjacent inorganic interlayer distance, PSCs based on LD (DMAPA)MAn-1PbnI3n+1 (n = 1) achieve a PCE of 3.85%, the currently highest PCE for PSCs based on n = 1 LD-DJP. The systematic study of the crystallization kinetics of DJPs with higher n values (n = 3, 4, 5) demonstrate that the perovskite quality is mainly dominated by the formation and decomposition of its intermediate phase. PSCs based on on n = 4 LD-DJP (DMAPA)MA3Pb4I13), with vertical crystal orientation, hierarchical phase distribution and low trap density, yield high PCEs up to 15.16%, and excellent stability with over 90% of the initial PCE retained without encapsulation after being stored at 85 °C in air for 1000 hours and ~80% PCE retained after 300-h of continous operation under 1-sun illumination in air.
关键词： Dion-Jacobson perovskites,perovskite solar cells,asymmetric alkyl diammonium,stability,Low-dimensional,power conversion efficiency
更新于2025-09-23 15:19:57
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Flexible and Selfa??Powered Lateral Photodetector Based on Inorganic Perovskite CsPbI <sub/>3</sub> a??CsPbBr <sub/>3</sub> Heterojunction Nanowire Array
摘要： Self-powered perovskite photodetectors mainly adopt the vertical heterojunction structure composed of active layer, electron–hole transfer layers, and electrodes, which results in the loss of incident light and interfacial accumulation of defects. To address these issues, a self-powered lateral photodetector based on CsPbI3–CsPbBr3 heterojunction nanowire arrays is designed on both a rigid glass and a flexible polyethylene naphthalate substrate using an in situ conversion and mask-assisted electrode fabrication method. Through adding the polyvinyl pyrrolidone and optimizing the concentration of precursors under the pressure-assisted moulding process, both the crystallinity and stability of perovskite nanowire array are improved. The nanowire array–based lateral device shows a high responsivity of 125 mA W?1 and a fast rise and decay time of 0.7 and 0.8 ms under a self-powered operation condition. This work provides a new strategy to fabricate perovskite heterojunction nanoarrays towards self-powered photodetection.
关键词： perovskites,photodetectors,flexible devices,self-powered
更新于2025-09-23 15:19:57
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Coordination Engineering of Singlea??Crystal Precursor for Phase Control in Ruddlesdena??Popper Perovskite Solar Cells
摘要： 2D Ruddlesden–Popper perovskites (RPPs) have recently drawn significant attention because of their structural variability that can be used to tailor optoelectronic properties and improve the stability of derived photovoltaic devices. However, charge separation and transport in 2D perovskite solar cells (PSCs) suffer from quantum well barriers formed during the processing of perovskites. It is extremely difficult to manage phase distributions in 2D perovskites made from the stoichiometric mixtures of precursor solutions. Herein, a generally applicable guideline is demonstrated for precisely controlling phase purity and arrangement in RPP films. By visually presenting the critical colloidal formation of the single-crystal precursor solution, coordination engineering is conducted with a rationally selected cosolvent to tune the colloidal properties. In nonpolar cosolvent media, the derived colloidal template enables RPP crystals to preferentially grow along the vertically ordered alignment with a narrow phase variation around a target value, resulting in efficient charge transport and extraction. As a result, a record-high power conversion efficiency (PCE) of 14.68% is demonstrated for a (TEA)2(MA)2Pb3I10 (n = 3) photovoltaic device with negligible hysteresis. Remarkably, superior stability is achieved with 93% retainment of the initial efficiency after 500 h of unencapsulated operation in ambient air conditions.
关键词： 2D perovskites,coordination engineering,phase distribution,perovskite solar cells,single-crystals
更新于2025-09-23 15:19:57
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Effect of Sr substitution on the air-stability of perovskite solar cells
摘要： By using a two-step spin-coating method, 10 mol% SrI2 and 10 mol% SrCl2-substituted perovskite films were synthesized and utilized to construct mesoscopic perovskite solar cells (PSCs), respectively. The influences of Sr substitutions on the humidity and thermal stability of PSCs were systematically investigated. It is indicated that both 10 mol% SrI2 substitution and 10 mol% SrCl2 substitution can enhance the power conversion efficiency (PCE) of PSC to more than 15%. The 10 mol% SrCl2 substitution can improve the humidity resistance of perovskite films, which is conducive to inhibiting the increase of perovskite’s defect density caused by humidity. After storing at 20±5 (cid:1), 30±5%RH for 21 d, the 10 mol% SrCl2-substituted PSC can still maintain 84% of the initial efficiency. However, the 10 mol% SrI2-substituted PSC exhibits a strong humidity sensitivity, which results in the increase of series resistance and the decrease of recombination impedance, thus making the PCE decrease to less than 20% of the initial value after storing at 20±5 (cid:1), 30±5%RH for 21 d. As for the thermal stability of PSCs, both the 10 mol% SrI2 and 10 mol% SrCl2-substituted perovskite films exhibit a certain thermal resistance. After 18 thermal cycles, both the 10 mol% SrI2 and 10 mol% SrCl2-substituted PSCs can maintain over 90% of the initial PCEs.
关键词： Perovskite solar cells,Sr-substituted perovskites,Humidity stability,Thermal stability
更新于2025-09-23 15:19:57
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Size- and Composition-Dependent Exciton Spin Relaxation in Lead Halide Perovskite Quantum Dots
摘要： The strong spin-orbital coupling in lead halide perovskites allows for facile spin injection for spintronics applications, but on the other hand also limits the lifetime of the injected spins. Full-dimensional confinement of the carriers using quantum dots (QDs) has been envisioned as an effective means to prolong the spin relaxation lifetime and has been explored for II-VI and III-V group QDs. Here we applied this idea to colloidal lead halide perovskite QDs and measured the exciton spin dynamics of QDs of varying sizes and compositions using circularly polarized transient absorption spectroscopy at room temperature. Interestingly, the spin lifetimes of CsPbI3 and CsPbBr3 QDs were prolonged and shortened, respectively, as compared to their bulk counterparts. Both CsPbI3 and CsPbBr3 QDs showed decreasing spin lifetime with decreasing QD size. Possible spin relaxation mechanisms, including those that are unique to these quantum-confined systems, were proposed, with important ramifications for the use of these perovskite QDs in spin-related applications.
关键词： lead halide perovskites,spin-orbital coupling,exciton spin dynamics,circularly polarized transient absorption spectroscopy,quantum dots
更新于2025-09-23 15:19:57
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Passivating contacts and tandem concepts: Approaches for the highest silicon-based solar cell efficiencies
摘要： The efficiency of photovoltaic energy conversion is a decisive factor for low-cost electricity from renewable energies. In recent years, the efficiency of crystalline silicon solar cells in mass production has increased annually by about 0.5–0.6%abs per year. In order to maintain this development speed, new technologies must be developed and transferred to industrial production. After the transition from full area Al back surface field cells to passivated emitter and rear contact cells, passivating contacts are an important step to get as close as possible to the efficiency limit of single junction Si solar cells. The theoretical background and the two prominent technologies for passivating contacts are presented and discussed. After implementing passivating contacts, the fundamental limit of single junction Si solar cells of 29.4% is in reach. Multi-junction solar cells are the most promising option to achieve efficiencies greater than 30%. Tandem technologies based on crystalline silicon as bottom cells have the advantage that they are based on a mature technology established on a gigawatt scale and can partially use the existing production capacity. In addition, silicon has an ideal bandgap for the lower subcell of a tandem solar cell. The two most promising material candidates for the top cell, i.e., III/V and perovskites, will be discussed. The presented technology routes show that silicon is able to maintain its outstanding position in photovoltaics in the coming years.
关键词： perovskites,multi-junction solar cells,III/V,photovoltaic energy conversion,passivating contacts,tandem technologies,crystalline silicon solar cells
更新于2025-09-23 15:19:57
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High-Performance UVa??Vis Photodetectors Based on a Lead-Free Hybrid Perovskite Crystal (MV)[SbI <sub/>3</sub> Cl <sub/>2</sub> ]
摘要： Low-dimensional lead-free organic?inorganic hybrid perovskites have gained increasing attention as having low toxicity, ease of processing, and good optoelectronic properties. Seeking for lead-free and narrow band gap organic?inorganic hybrid perovskites are of great importance for the development and application of photoelectric materials. Here, we reported a Sb-based organic?inorganic hybrid perovskite (MV)[SbI3Cl2], which has one-dimensional inorganic frameworks of the I-sharing double octahedra. (MV)[SbI3Cl2] shows a narrow direct band gap of 1.5 eV, and displays obvious photoresponse for the 532 nm light with rapid response speed of trise = 0.69 s, tdecay = 0.28 s. With an illumination power of 5 mW and a 50 V bias, the responsivities (R) and external quantum e?ciency (EQE) for (MV)[SbI3Cl2] photodetector under 532 nm laser are 29.75 mA/W and 6.69% respectively. This Sb-based halide double perovskite material will provide an alternative material for photodetector devices.
关键词： organic?inorganic hybrid perovskites,Sb-based,narrow band gap,photodetectors,lead-free
更新于2025-09-23 15:19:57