Publications by Ulf Anders Hagfeldt

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Light-induced degradation in metal halide perovskites is a major concern that can potentially hamper the commercialization of perovskite optoelectronic devices. The phenomena viz. ion migration, phase segregation, and defect intolerance are believed to be ...

Mesoporous carbon (MC)-imbedded tungsten carbide (W2C) composites are synthesized via a simple methodology and subsequently used as flexible counter electrodes (CEs) in dye-sensitized solar cells (DSCs). The W2C/MC composite possesses remarkable electroche ...

Two cyanobiphenyl liquid crystals (LCs), 5CB (4-cyano-4'-pentylbiphenyl) and 8CB (4-cyano-4'-octylbiphenyl), are introduced as additives into Co(II/ III) electrolytes for dye-sensitized solar cells (DSCs). An electrolyte containing a combination of these L ...

Growing large, oriented grains of perovskite often leads to efficient devices, but it is unclear if properties of the grains are responsible for the efficiency. Domains observed in SEM are commonly misidentified with crystallographic grains, but SEM images ...

Organometal halide perovskite solar cells have demonstrated high conversion efficiency but poor long-term stability against ultraviolet irradiation and water. We show that rapid light-induced free-radical polymerization at ambient temperature produces mult ...

A two-step deposition technique is used for preparing CH3NH3PbI3 perovskite solar cells. Using ZrO2 and TiO2 as a mesoporous layer, we obtain an efficiency of 10.8% and 9.5%, respectively, under 1000 W m(-2) illumination. The ZrO2 based solar cell shows hi ...

Perovskite solar cells based on CH3NH3PbI3 and related materials have reached impressive efficiencies that, on a lab scale, can compete with established solar cell technologies, at least in short-term observations. Despite frequently voiced concerns about ...

The employment of 2D perovskites is a promising approach to tackling the stability and voltage issues inherent in perovskite solar cells. It remains unclear, however, whether other perovskites with different dimensionalities have the same effect on efficie ...

A semitransparent, flexible single-walled carbon nanotube (SWCNT) film was efficiently used in place of evaporated silver as the counter electrode of a poly(3,4-ethylenedioxythiophene) polymer-based solid-state dye solar cell (SSDSC): the solar-to-electric ...

A cobalt-catalyzed cyclotrimerization of bis(aryl)alkyne is used as an innovative tool to obtain hole-transport materials (HTMs). The novel HTM containing six units of oligotriarylamine (HAB1), characterized by UV-vis, cyclic voltammetry, DFT, and thermogr ...

Pt/carbon fiber composite (Pt/Cf) with a low Pt loading of 1.0 wt% is introduced into dye-sensitized solar cells as counter electrode (CE) catalyst. The cobalt-electrolyte based device using this composite CE achieves power conversion efficiency of 8.97%, ...

With Ru-II(bpyMeP)(2)tpphzPtCl(2) (4) a molecular photocatalyst has been synthesized for visible-light-driven H-2-evolution. It contains the ligand bpyMeP (4,4'-bis(diethyl-(methylene)-phosphonate)-2,2'-bipyridine) with phosphate ester groups as prec ...

Mixtures of cations or halides with FAPbI(3) (where FA is formamidinium) lead to high efficiency in perovskite solar cells (PSCs) but also to blue-shifted absorption and long-term stability issues caused by loss of volatile methylammonium (MA) and phase se ...

Power conversion efficiency (PCE) of the perovskite solar cells (PSCs) has remarkably been increased from3.1%to 25.2%. The fast expansion of the PSCs has been along with the development of compositional and interface engineering, which has been playing a c ...

We demonstrate that by a proper design of a system comprising a perovskite solar cell (PSC) coupled to an electrochemical double-layer capacitor (EDLC), it is possible to simultaneously improve both the PSC and EDLC performance and outperform each single u ...

Two new dyes, E1 and E2, equipped with triphenylamine as the electron donor, oligothiophene as the linker and different electron acceptor groups, have been designed and synthesized as photosensitizers for p-type dye-sensitized solar cells (p-DSCs). A syste ...

We report a novel electron-rich molecule based on 3,4-ethylenedioxythiophene (H101). When used as the hole-transporting layer in a perovskite-based solar cell, the power-conversion efficiency reached 13.8% under AM 1.5G solar simulation. This result is com ...

In this study, a new mechanism for doping of spiro-MeOTAD by Zn(TFSI)(2) is revealed, which is completely different from the mechanism induced by LiTFSI. The oxidation of spiro-MeOTAD is facilitated by complexation between the zinc cation and tert-butylpyr ...

Lead halide perovskites have a range of spectacular properties and interesting phenomena and are a serious candidate for the next generation of photovoltaics with high efficiencies and low fabrication costs. An interesting phenomenon is the anomalous hyste ...

Ulf Anders Hagfeldt

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Understanding and decoupling the role of wavelength and defects in light-induced degradation of metal-halide perovskites

Mesoporous carbon-imbedded W2C composites as flexible counter electrodes for dye-sensitized solar cells

Photovoltage enhancement from cyanobiphenyl liquid crystals and 4-tert-butylpyridine in Co(II/III) mediated dye-sensitized solar cells

Crystal Orientation and Grain Size: Do They Determine Optoelectronic Properties of MAPbI(3) Perovskite?

Improving efficiency and stability of perovskite solar cells with photocurable fluoropolymers

Using a two-step deposition technique to prepare perovskite (CH3NH3PbI3) for thin film solar cells based on ZrO2 and TiO2 mesostructures

Proof-of-concept for facile perovskite solar cell recycling

Passivation Mechanism Exploiting Surface Dipoles Affords High-Performance Perovskite Solar Cells

Carbon nanotube film replacing silver in high-efficiency solid-state dye solar cells employing polymer hole conductor

Perovskite Solar Cells Based on Oligotriarylamine Hexaarylbenzene as Hole-Transporting Materials

Synthesis of highly effective Pt/carbon fiber composite counter electrode catalyst for dye-sensitized solar cells

Synthesis and characterization of an immobilizable photochemical molecular device for H-2-generation

Vapor-assisted deposition of highly efficient, stable black-phase FAPbI(3) perovskite solar cells

Compositional and Interface Engineering of Organic-Inorganic Lead Halide Perovskite Solar Cells

Perovskite solar cell - electrochemical double layer capacitor interplay

A study of oligothiophene-acceptor dyes in p-type dye-sensitized solar cells

A Simple 3,4-Ethylenedioxythiophene Based Hole-Transporting Material for Perovskite Solar Cells

The Role of 3D Molecular Structural Control in New Hole Transport Materials Outperforming Spiro-OMeTAD in Perovskite Solar Cells

Revealing the Mechanism of Doping of spiro-MeOTAD via Zn Complexation in the Absence of Oxygen and Light

Photon Energy-Dependent Hysteresis Effects in Lead Halide Perovskite Materials