A5100361747- Perovskite Materials and Applications
- Quantum Dots Synthesis And Properties
- Solid-state spectroscopy and crystallography
- Conducting polymers and applications
- Chalcogenide Semiconductor Thin Films
- Semiconductor Quantum Structures and Devices
- 2D Materials and Applications
- Organic Light-Emitting Diodes Research
- Luminescence Properties of Advanced Materials
- Organic and Molecular Conductors Research
- Optical properties and cooling technologies in crystalline materials
- Ga2O3 and related materials
- Crystal Structures and Properties
- Advanced Semiconductor Detectors and Materials
- Integrated Circuits and Semiconductor Failure Analysis
- Luminescence and Fluorescent Materials
- Acoustic Wave Resonator Technologies
- Organic Electronics and Photovoltaics
Lund University
2018-2023
Nankai University
2023
Liaoning University
2022
State Key Laboratory of Silicon Materials
2021
Zhejiang University
2021
NOAA Chemical Sciences Laboratory
2021
Abstract Organo-metal halide perovskites are promising solution-processed semiconductors, however, they possess diverse and largely not understood non-radiative mechanisms. Here, we resolve contributions of individual recombination centers (quenchers) in nanocrystals methylammonium lead iodide by studying their photoluminescence blinking caused random switching quenchers between active passive states. We propose a model to describe the observed reduction upon cooling determine energetic...
Abstract Molecular additives are widely utilized to minimize non-radiative recombination in metal halide perovskite emitters due their passivation effects from chemical bonds with ionic defects. However, a general and puzzling observation that can hardly be rationalized by alone is most of the molecular enabling high-efficiency light-emitting diodes (PeLEDs) chelating (multidentate) molecules, while respective monodentate counterparts receive limited attention. Here, we reveal largely...
Abstract Although the 2D spacer modification is widely studied in perovskite solar cells (PVSCs), energy level alignment between 2D/3D interfaces makes it unfavorable for top surface passivation inverted p‐i‐n device structure. To address this issue, effect of bottom interface with three representative spacers, i.e., Ruddlesden‐Popper spacer, Dion‐Jacobson and strong PVSCs. After optimization, PVSCs these modifications universally exhibit best efficiencies ≈21.6%, which constitutes dramatic...
Nonradiative losses in semiconductors are related to defects. At cryogenic temperatures, defect-related photoluminescence (PL) at energies lower than the band-edge PL is observed methylammonium lead triiodide perovskite. We applied multispectral imaging samples prepared by two different procedures and exhibiting 1 order of magnitude quantum yield (PLQY). The high-PLQY sample showed concentration emitting defect sites around 1012-1013 cm-3. No correlation between PLQY relative intensity...
Abstract Antibunching effect is typically observed in individual systems possessing photoluminescence (PL) blinking and vice versa. Contrary to this common perception, absence of antibunching strongly methyl ammonium led tri‐iodide (MAPbI 3 ) perovskite crystals sizes from tens hundreds nanometers regardless the excitation power density observed. does not appear even when photon statistics are analyzed for bright intermediate PL intensity levels independently. This shows that there no...
Abstract Metal halide perovskites are an important class of emerging semiconductors. Their charge carrier dynamics is poorly understood due to limited knowledge defect physics and recombination mechanisms. Nevertheless, classical ABC Shockley-Read-Hall (SRH) models ubiquitously applied without considering their validity. Herein, advanced technique mapping photoluminescence quantum yield (PLQY) as a function both the excitation pulse energy repetition frequency developed employed examine...
Preparation of metal-halide perovskites under room temperature attracts attention because energy saving by removing thermal annealing. Room-temperature transformation spin-cast wet films consisting methylammonium (MA) iodide, PbI2, and dimethylformamide toward solid MAPbI3 perovskite proceeds via several intermediate crystalline states is strongly dependent on ambient humidity. Light transmission photoluminescence (PL) microscopy spectroscopy were used to monitor the growth crystals their...
Metal halide perovskites show great promise for a wide range of optoelectronic applications but are plagued by instability when exposed to air and light. This work presents low-temperature solution growth vertically aligned CsPbBr3 nanowire arrays in AAO (anodized aluminum oxide) templates with excellent stability, samples 4 months still exhibiting comparable photoluminescence UV stability fresh samples. The single-crystal length is adjusted from ∼100 nm 5 μm adjusting the precursor amount...
Time-resolved analysis of photon cross-correlation function g(2)(τ) is applied to photoluminescence (PL) individual submicrometer size MAPbI3 perovskite crystals. Surprisingly, an antibunching effect in the long-living tail PL observed, while prompt obeys statistics typical for a classical emitter. We propose that antibunched photons from decay originate radiative recombination detrapped charge carriers which were initially captured by very limited number (down one) shallow defect states....
Abstract The photoluminescence (PL) of metal halide perovskites can recover after light or current‐induced degradation. This self‐healing ability is tested by acting mechanically on MAPbI 3 polycrystalline microcrystals an atomic force microscope tip (applying force, scratching, and cutting) while monitoring the PL. Although strain crystal damage induce strong PL quenching, initial balance between radiative nonradiative processes in restored within a few minutes. stepwise quenching–recovery...
Abstract The fate of excited charge carriers in metal halide perovskite semiconductors is influenced by energetic disorder and defects. Here, photoluminescence (PL) blinking used to probe metastable nonradiative (NR) centers the nanoscale energy landscape. Temporal activation an NR center creates a local region with increased recombination. Activation deactivation this PL quenching does not only lead blinking, but also fluctuations spectra, if crystal inhomogeneous sense that emission...
Abstract Metal halide perovskites are promising optoelectronic materials. Their electronic properties however rather unstable which is often assigned to ion migration. Ion migration can be readily influenced by an electric field (EF). Here, the response of photoluminescence (PL) individual MAPbX 3 (MA = CH NH , X I, Br) sub‐micrometer‐sized polycrystals EF studied. Alternating with frequency higher than 10 Hz found reversibly quench PL. It proposed that alternating when applied together...
Recently, research on the edge states of 2D lead halide perovskites (LHPs) has been attracting much attention. The lower‐energy state (LES) is believed to provide an efficient pathway for dissociation photoexcited excitons. However, mechanism LES formation remains controversial, and studies that establish precisely local electronic properties are lacking. Herein, first study spatially resolved structures in LHP single‐crystal flakes by X‐ray photoemission electron microscopy presented,...
Inorganic CsPbBr3 perovskite solar cells (PSCs) have attracted wide attention due to their low cost and excellent resistance ultraviolet light, oxygen, temperature. However, the mechanism of crystallization is relatively complex lower solubility CsBr in N,N-dimethylformamide. Also, excessively high valence band offset between a hole transport layer (HTL), such as Spiro-OMeTAD, main factor limiting improvement efficiency. Herein, based on top-down vertical polycrystalline prepared by...
Organo metal halide perovskites are solution processed semiconductors that recently attracted a great attention. They possess rather “soft” and (photo) chemically active solid structure allowing for ion migration other mass diffusion processes. This is likely reason why non-radiative recombination centres in these materials activated deactivated on relatively slow time-scales. dynamics reveals as photoluminescence (PL) fluctuations (blinking) of individual microcrystals local areas films...
The TiO 2 conversion luminescent materials doped with different ratios of Er 3+ and Yb rare earth ions are used as the electron transport layer under scattered solar light irradiation by prism to enhance photoelectric performance CH 3 NH PbI perovskite cells (MAPbI PSC). up-conversion down-conversion films were prepared sol-gel method. composition morphology determined XRD, XPS SEM. optical properties characterized UV-vis PL spectra. film can absorb multiple low energy infrared photons...
The ancient technology of colouring by mechanical rubbing a dry pigment onto surfaces can be applied to metal halide perovskites, enabling the fabrication highly luminescent templated micro and nano arrays.