Variable definitions.

Variable definitions.</p

Address endogeneity problems.

Address endogeneity problems.</p

Sample selection process.

Sample selection process.</p

Robustness test.

Robustness test.</p

Audit firm’s culture as a selection mechanism.

Audit firm’s culture as a selection mechanism.</p

The direct effect of audit office’s culture on auditor’s behavior.

The direct effect of audit office’s culture on auditor’s behavior.</p

Descriptive statistics.

Descriptive statistics.</p

Benchmark regression.

Benchmark regression.</p

Solvent-Assisted Self-Assembly of Fullerene into Single-Crystal Ultrathin Microribbons as Highly Sensitive UV–Visible Photodetectors

The size, shape, and crystallinity of organic nanostructures play an important role in their physical properties and are mainly determined by the self-assembling kinetics of molecular components often involving the solvent conditions. Here, we reported a kinetically controlled self-assembly of C₆₀ assisted by the solvent carbon bisulfide (CS₂) into single-crystal ultrathin microribbons of 2C₆₀·3CS₂, upon mixing the poor solvent isopropyl alcohol with a C₆₀/CS₂ stock solution. Surface energy calculations reveal that these microribbons represent a kinetically favored high-energy state as compared with the thermodynamically stable shape of prismatic rods. High-resolution transmission electron microscopy observations clarify that association of CS₂ at the nucleation stage helps to guide and rigidify the formation of π–π stacking 1D chains of C₆₀ through the surrounding CS₂ cage-like structures, which further act as glue, boosting lateral assembly of as-formed 1D chains into untrathin 2D microribbon single crystals. Precise control over the thickness, width, and length of 2C₆₀·3CS₂ microribbons was achieved by manipulation of the growth kinetics through adjusting the solvent conditions. Upon heating to 120 °C, sublimation of CS₂ components results in fcc C₆₀ microribbons. We found that both microribbons of solvated monoclinic 2C₆₀·3CS₂ and pure fcc C₆₀ exhibit highly sensitive photoconductivity properties with a spectral response range covering UV to visible. The highest on/off ratio of two-terminal photodetectors based on single ribbons reaches around 250, while the responsitivity is about 75.3 A W^–1 in the UV region and 90.4 A W^–1 in the visible region

Fullerene Hollow Microspheres Prepared by Bubble-Templates as Sensitive and Selective Electrocatalytic Sensor for Biomolecules

We developed an electrocatalytic sensor based on C60 hollow microspheres for highly sensitive and selective detection of dopamine (DA) in the presence of ascorbic acid (AA), and uric acid (UA) in the presence of l-cysteine (RSH). The hollow microspheres of C60 with a diameter controllable in the range of 0.5 to 1.5 μm and a thickness of 200 nm are synthesized by a high-temperature reprecipitation method with the assistance of alcohol bubbles. The superhydrophobicity of C60 hollow microspheres makes them capable of forming a compact thin film at air/water interface, which can be readily transferred on the surface of gold or glassy carbon electrodes. This porous C60 film made from C60 hollow microspheres shows a specific surface area as high as 107 m2 g–1. In order to obtain a conducting film, the C60-modified electrode is pretreated by scanning the potential range from 0.0 to −1.5 V in 1 M KOH followed by potential cycling between 550 to −50 mV in a pH 7.2 phosphate buffer solution. On the basis of XPS and IR measurements, we found that surface oxides, such as −OH and CO groups, are introduced on the surfaces of the conducting C60 film. This, combined with the porosity that enhances the adsorption activity of C60-modified electrodes, enable the electrocatalytic analysis of target biomolecules with detection limit as low as 0.1 nM for DA in the presence of AA, and 1 μM for UA in the presence of RSH