A5061989085- Perovskite Materials and Applications
- Conducting polymers and applications
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Solid-state spectroscopy and crystallography
- Organic Electronics and Photovoltaics
- Silicon and Solar Cell Technologies
- Luminescence Properties of Advanced Materials
- Gas Sensing Nanomaterials and Sensors
- Radiation Detection and Scintillator Technologies
- Organic and Molecular Conductors Research
- Crystal Structures and Properties
- Advanced Photocatalysis Techniques
University of Washington
2020-2025
Georgia Institute of Technology
2023
Drawing from both experimental data and simulation, we highlight best practices for fitting time-resolved photoluminescence (TRPL) decays of halide perovskite semiconductors, which are now widely studied applications in photovoltaics light-emitting diodes (LEDs). First, at low excitation intensities, high-quality perovskites often show pseudo-first-order kinetics, consistent with classic minority carrier lifetimes. Second, multiexponential decays, frequently observed have significant...
We show that adding ethylenediamine (EDA) to perovskite precursor solutions improves the photovoltaic device performance and material stability of high-bromide-content, methylammonium-free, formamidinium cesium lead halide perovskites FA1–xCsxPb(I1–yBry)3, which are currently interest for perovskite-on-Si tandem solar cells. Using spectroscopy hyperspectral microscopy, we additive film homogeneity suppresses phase instability is ubiquitous in high-Br formulations, producing films remain...
We demonstrate reduced surface recombination velocity (SRV) and enhanced power-conversion efficiency (PCE) in mixed-cation mixed-halide perovskite solar cells by using (3-aminopropyl)trimethoxysilane (APTMS) as a passivator. show the APTMS serves to passivate defects at surface, while also decoupling from detrimental interactions C60 interface. measure SRV of ∼125 ± 14 cm/s, concomitant increase ∼100 meV quasi-Fermi level splitting passivated devices compared controls. use time-resolved...
Humid atmosphere annealing enhances interdiffusion in sequentially evaporated perovskites, leading to improved crystallinity and reduced non-radiative recombination. This boosts PLQY raises PCE 21.0%, while enhancing stability under 85 °C full-spectrum illumination.
We control surface recombination in the mixed-cation, mixed-halide perovskite, FA0.83Cs0.17Pb(I0.85Br0.15)3, by passivating nonradiative defects with polymerizable Lewis base (3-aminopropyl)trimethoxysilane (APTMS). demonstrate average minority carrier lifetimes >4 μs, nearly single exponential monomolecular photoluminescence decays, and high external quantum efficiencies (>20%, corresponding to ∼97% of maximum theoretical quasi-Fermi-level splitting) at low excitation fluence. confirm both...
Interfacial passivation with bulky organic cations such as phenetylammonium iodide has enabled high performance for metal halide perovskite optoelectronic devices. However, the homogeneity of these interfaces and their formation dynamics are poorly understood. We study how Ruddlesden–Popper 2D phases form at a 3D interface when precursors introduced via solution or vapor. When using vapor deposition, we observe uniform coverage capping layer predominantly n = 2 phase. In contrast, presence...
While amines are widely used as additives in metal-halide perovskites, our understanding of the way perovskite precursor solutions impact resultant film is still limited. In this paper, we explore multiple effects benzylamine (BnAm), also referred to phenylmethylamine, passivate both FA
We use multimodal microscopy to study carrier recombination in semiconducting tin halide perovskite films based on PEA0.2FA0.8SnI3 (PEA = phenethylammonium; FA formamidinium). the observation of pseudo-first-order photoluminescence (PL) decay kinetics establish a method for quantifying hole dopant level and nonradiative rate constant. find that untreated exhibit large doping concentrations p0 ≈ 1019 cm–3, which is reduced 1016 cm–3 after SnF2 treatment. While it well-known radiative rates...
Abstract Compositional heterogeneity in wide-bandgap (1.8 − 2.1 eV) mixed-halide perovskites is a key bottleneck the processing of high-quality solution-processed thin films and prevents their application efficient multijunction solar cells. Notably, mixed-cation (formamidinium-methylammonium) perovskite are prone to form micrometer-scale wrinkles which can interfere with smooth surfaces ideal for devices. Here, we study formation dynamics wrinkled its impact on local composition...
We copolymerize a norbornene monomer bearing pendant naphthalene diimide with cinnamate moiety to synthesize crosslinkable electron-transporting polymer and study its use in solution-processed n–i–p perovskite solar cells. The crosslinked material exhibits over 90% transparency the visible region higher thermal stability (>300 °C) lower surface energy than corresponding homopolymer of functionalized norbornene. Coating an ITO photo-crosslinked copolymer yields slightly work function...
We report positive and negative ion time-of-flight secondary mass spectrometry (ToF-SIMS) spectra of metal-halide perovskite (MHP) films used for photovoltaic applications. This ToF-SIMS spectral library is importance because it identifies the major peaks in most MHP from organic [formamidinium (FA+)] inorganic (Cs+) cations anions (I− Br−).
Abstract Solution‐processed organic and hybrid semiconductor materials have great potential for ionizing radiation direct detection, as they combine high sensitivity, low‐power consumption, flexibility. There is, however, an open challenge related to the stability in ambient/operational conditions of this class devices. In work, air‐stable, solution‐processed flexible X‐ray detector is reported, based on integration perovskite thin films used active layer functional interlayers,...
Antisolvent treatment is used in the fabrication of perovskite films to control grain growth during spin coating. We study widely incorporated aromatic hydrocarbons and aprotic ethers, discussing origin their performance differences 2D/3D Sn (PEA0.2FA0.8SnI3) solar cells. Among antisolvents that we screen, diisopropyl ether yields highest power conversion efficiency use a combination optical structural characterization techniques reveal this improved originates from higher concentration 2D...
<title>Abstract</title> Compositional heterogeneity in wide-bandgap (1.8 − 2.1 eV) mixed-halide perovskites is a key bottleneck the processing of high-quality solution-processed thin films, and prevents their application efficient multijunction solar cells. Notably, mixed-cation (formamidinium-methylammonium) perovskite films are prone to form micrometer-scale wrinkles which can interfere with smooth surfaces ideal for devices. Here, we study formation dynamics wrinkled its impact on local...
We show that the use of 1,3-diaminopropane (DAP) as a chemical modifier at perovskite/electron-transport layer (ETL) interface enhances power conversion efficiency (PCE) 1.7 eV bandgap FACs mixed-halide perovskite single-junction cells, primarily by boosting open-circuit voltage (VOC) from 1.06 V to 1.15 V. Adding post-processing annealing step after C60 evaporation, further improves fill factor (FF) 20% control DAP + post-annealing devices. Using hyperspectral photoluminescence microscopy,...
We demonstrate the critical role of surface recombination in mixed-cation, mixed-halide perovskite, FA0.83Cs0.17Pb(I0.85Br0.15)3. By passivating non-radiative defects with polymerizable Lewis base (3-aminopropyl)trimethoxysilane (APTMS) we transform these thin films. average minority carrier lifetimes > 4 {\mu}s, nearly single exponential monomolecular PL decays, and concomitantly high external photoluminescence quantum efficiencies (>20%, corresponding to ~97% maximum theoretical...
Halide perovskites have attracted tremendous research interest due to their potential applications in photovoltaics. In this work, we demonstrate reduced surface recombination velocity (SRV) and enhanced power-conversion efficiency (PCE) mixed-cation mixed-halide perovskite solar cells by using a passivator of (3-aminopropyl)trimethoxysilane (APTMS). We show that APTMS passivates defects at the surface, while also decoupling from detrimental interactions C60 interface. measure an increase...
This presentation demonstrates recent advances in reducing the surface recombination velocity and provides insights to develop passivating molecules that help reduce MA-free mixed-cation mixed-halide films.
We demonstrate reduced surface recombination velocity (SRV) and enhanced power-conversion efficiency (PCE) in mixed-cation mixed-halide perovskite solar cells by using (3-aminopropyl)trimethoxysilane (APTMS) as a passivator. show the APTMS serves to passivate defects at surface, while also decoupling from detrimental interactions C60 interface. measure SRV of ~125 + 14 cm/s, concomitant increase ~100 meV quasi-Fermi level splitting passivated devices compared controls. use time-resolved...
We show that adding ethylenediamine (EDA) to perovskite precursor solution improves the photovoltaic device performance and material stability of high-bromide-content, methylammonium-free, formamidinium cesium lead halide perovskites FA1-xCsxPb(I1-yBry)3 which are currently interest for perovskite-on-Si tandem solar cells. Using spectroscopy hyperspectral microscopy, we additive film homogeneity suppresses phase instability is ubiquitous in high-Br formulations, producing films remain stable...