The interparticle distance limit for multiple exciton dissociation in PbS quantum dot solid films.

Understanding the behaviour of multiple exciton dissociation in quantum dot (QD) solid films is of fundamental interest and paramount importance for improving the performance of quantum dot solar cells (QDSCs). Unfortunately, the charge transfer behaviour of photogenerated multiple exciton in QD solid films is not clear to date. Herein, we systematically investigate the multiple exciton charge transfer behaviour in PbS QD solid films by using ultrafast transient absorption spectroscopy.

Interface Passivation Effects on the Photovoltaic Performance of Quantum Dot Sensitized Inverse Opal TiO₂ Solar Cells.

Quantum dot (QD)-sensitized solar cells (QDSSCs) are expected to achieve higher energy conversion efficiency than traditional single-junction silicon solar cells due to the unique properties of QDs. An inverse opal (IO)-TiO₂ (IO-TiO₂) electrode is useful for QDSSCs because of its three-dimensional (3D) periodic nanostructures and better electrolyte penetration compared to the normal nanoparticles (NPs)-TiO₂ (NPs-TiO₂) electrode. We find that the open-circuit voltages of the QDSSCs with IO-TiO₂ electrodes are higher than those of QDSSCs with NPs-TiO₂ electrodes.

Lead Selenide Colloidal Quantum Dot Solar Cells Achieving High Open-Circuit Voltage with One-Step Deposition Strategy.

Lead selenide (PbSe) colloidal quantum dots (CQDs) are considered to be a strong candidate for high-efficiency colloidal quantum dot solar cells (CQDSCs) due to its efficient multiple exciton generation. However, currently, even the best PbSe CQDSCs can only display open-circuit voltage ( V) about 0.530 V.

Highly Luminescent Phase-Stable CsPbI Perovskite Quantum Dots Achieving Near 100% Absolute Photoluminescence Quantum Yield.

Perovskite quantum dots (QDs) as a new type of colloidal nanocrystals have gained significant attention for both fundamental research and commercial applications owing to their appealing optoelectronic properties and excellent chemical processability. For their wide range of potential applications, synthesizing colloidal QDs with high crystal quality is of crucial importance. However, like most common QD systems such as CdSe and PbS, those reported perovskite QDs still suffer from a certain density of trapping defects, giving rise to detrimental nonradiative recombination centers and thus quenching luminescence.

Recombination Suppression in PbS Quantum Dot Heterojunction Solar Cells by Energy-Level Alignment in the Quantum Dot Active Layers.

Using spatial energy-level gradient engineering with quantum dots (QDs) of different sizes to increase the generated carrier collection at the junction of a QD heterojunction solar cell (QDHSC) is a hopeful route for improving the energy-conversion efficiency. However, the results of current related research have shown that a variable band-gap structure in a QDHSC will create an appreciable increase, not in the illumination current density, but rather in the fill factor. In addition, there are a lack of studies on the mechanism of the effect of these graded structures on the photovoltaic performance of QDHSCs.

High Efficiency Quantum Dot Sensitized Solar Cells Based on Direct Adsorption of Quantum Dots on Photoanodes.

Unambiguously direct adsorption (DA) of initial oil-soluble quantum dots (QDs) on TiO film electrode is a convenient and simple approach in the construction of quantum dot sensitized solar cells (QDSCs). Regrettably, low QD loading amount and poor reproducibility shadow the advantages of DA route and constrain its practical application. Herein, the influence of experimental variables in DA process on QD loading amount as well as on the photovoltaic performance of the resultant QDSCs was investigated and optimized systematically, including the choice of solvent, purification of QDs, and sensitization time, as well as QD concentration.

Alloying Strategy in Cu-In-Ga-Se Quantum Dots for High Efficiency Quantum Dot Sensitized Solar Cells.

I-III-VI group "green" quantum dots (QDs) are attracting increasing attention in photoelectronic conversion applications. Herein, on the basis of the "simultaneous nucleation and growth" approach, Cu-In-Ga-Se (CIGSe) QDs with light harvesting range of about 1000 nm were synthesized and used as sensitizer to construct quantum dot sensitized solar cells (QDSCs). Inductively coupled plasma atomic emission spectrometry (ICP-AES), wild-angle X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses demonstrate that the Ga element was alloyed in the Cu-In-Se (CISe) host.

Photoreceptor images of normal eyes and of eyes with macular dystrophy obtained in vivo with an adaptive optics fundus camera.

Purpose: To report on images of the human photoreceptor mosaic acquired in vivo with a newly developed, compact adaptive optics (AO) fundus camera.

Methods: The photoreceptors of two normal subjects and a patient with macular dystrophy were examined by using an AO fundus camera equipped with a liquid crystal phase modulator. In the eye with macular dystrophy, the fixation point in the AO images was identified using scanning laser ophthalmoscope (SLO) microperimetric image superimposed on a color fundus photograph.

Binocular open-view Shack-Hartmann wavefront sensor with consecutive measurements of near triad and spherical aberration.

We have developed a binocular open-view Shack-Hartmann wavefront sensor for measuring time variation of binocular accommodation, vergence, pupil sizes (i.e., the binocular near triad), and monochromatic aberrations.

Adaptive optics fundus camera to examine localized changes in the photoreceptor layer of the fovea.

Purpose: To examine highly localized photoreceptor disruptions in the fovea by a high-resolution adaptive optics (AO) fundus camera combined with Fourier-domain optical coherence tomography (FD OCT).

Design: Observational case series.

Participants: Three eyes of 3 patients who showed dark foveal spots by slit-lamp biomicroscopy.

In vivo measurements of cone photoreceptor spacing in myopic eyes from images obtained by an adaptive optics fundus camera.

Purpose: To determine the cone spacing in normal and myopic eyes from the images obtained by an adaptive optics (AO) fundus camera.

Methods: Nineteen eyes of 19 healthy volunteers with a mean +/- SD spherical equivalent refractive error of -3.7 +/- 3.