Low cost photovoltaic modules based on dye sensitized nanocrystalline titanium dioxide and carbon powder

Thin-film solar cells

Physics of Amorphous Silicon–Carbon Alloys

Enhancing the performance of building integrated photovoltaics

The commercial manufacturing of perovskite solar modules (PSM) suffers from stability concerns and scalability issues. We demonstrate a hole-conductor-free printable solar module embodiment, which employs a triple layer of mesoporous TiO2/ZrO2/carbon as scaffold, and is infiltrated by a mixed cation lead halide perovskite (5-AVA)x(MA)1−xPbI3 as a light harvester. Here, hole conductor or Au reflector are not employed, and instead, the back contact comprises simply a printed carbon layer. Upon optimizing the thickness alignment of the triple mesoscopic layer and the design of the active area, the unit cell shows 14.02% power conversion efficiency (PCE) under 100 mW cm−2 condition, while a larger area of 10 serially connected cells module (10 × 10 cm2), shows a 10.4% PCE on an active area of 49 cm2. Light-soaking stability of 1000 h has been demonstrated, as well as local outdoor stability of 1 month and a shelf-life stability of over 1 year. This paves the way for the realization of efficient and stable large-area PSMs for industrial deployment.

Stable Large-Area (10 × 10 cm2) Printable Mesoscopic Perovskite Module Exceeding 10% Efficiency

The influence of the Si-H2 bond on light-induced degradation and the thermal recovery of a-Si films and a-Si solar cells were studied. The influence of the Si-H2 bond on light-induced degradation depends on the impurity content in a-Si films, and light-induced degradation can be reduced by decreasing the Si-H2 bond density in a-Si films with impurity content of 1018 cm-3. The activation energy of the thermal recovery process was about 1.0 eV, and it did not depend on the Si-H2 bond density. However, an irreversible phenomenon was observed in film properties and solar cell characteristics with high Si-H2 bond density. It is thought that the structural flexibility of the Si-H2 bond is related to this irreversible phenomenon.

https://iopscience.iop.org/article/10.1143/JJAP.28.1762/pdf

The Influence of the Si-H2 Bond on the Light-Induced Effect in a-Si Films and a-Si Solar Cells

A laser patterning method was investigated as a fabrication method for integrated-type amorphous-silicon (a-Si) solar cell submodules. A three-dimensional thermal analysis of a multilayer structure was performed to determine the selective scribing conditions for each layer of an a-Si solar cell. The optimum laser power densities calculated from a three-dimensional thermal analysis were confirmed by the experiments. It was found that not only transparent conductive oxide and a-Si films, but also the metal electrodes of the integrated-type a-Si solar cell submodule were selectively scribed. The total output power of an a-Si solar cell submodule patterned by optimum laser-power densities was 9% higher than that achieved by a conventional patterning method.

Laser Patterning Method for Integrated Type a-Si Solar Cell Submodules

A separated ultra-high vacuum (UHV) reaction chamber system, called the super chamber, has been newly developed. A background pressure of 10-9 Torr was obtained, and the impurity concentrations of oxygen, nitrogen and carbon in an a-Si film fabricated in the super chamber were 2×1018 cm-3, 1×1017 cm-3, and 2×1018 cm-3, respectively. The space charge density and the ESR spin density of the a-Si film were 5×1014 cm-3 and 2×1015 cm-3, respectively. These values were much lower than those for films fabricated in a conventional chamber. The ratio of the light-induced degradation in the photoconductivity of the a-Si film was also small compared with that of conventional a-Si films. A conversion efficiency of 11.7% was obtained for a glass/textured TCO/pin/Ag a-Si solar cell, whose i-layer was fabricated in the super chamber.

http://iopscience.iop.org/article/10.1143/JJAP.26.33/pdf

Preparation and Properties of High-Quality a-Si Films with a Super Chamber (Separated Ultra-High Vacuum Reaction Chamber)

Development and application of see-through a-Si solar cells

A new method of preparing a-Si film, in which each of the p, i, and n layers are deposited in consecutive, separated reaction chambers, is presented. It was confirmed experimentally that, in the conventional single reaction chamber method for a-Si film, the residual dopant gases which remain in the reaction chamber cause undesirable doping of the film, resulting in deterioration of the film quality. This undesirable doping can be avoided in the separated reaction chamber method. The photoconductivity of the i-layer prepared by this method was about 1×10-3 (Ω-1cm-1) in sunlight of AM–1 100 mW/cm-2. The best conversion efficiency of p-i-n a-Si solar cells prepared by this method was 6.91%.

Michitoshi Ohnishi

Papers

The Influence of the Si-H2 Bond on the Light-Induced Effect in a-Si Films and a-Si Solar Cells

Laser Patterning Method for Integrated Type a-Si Solar Cell Submodules

Preparation and Properties of High-Quality a-Si Films with a Super Chamber (Separated Ultra-High Vacuum Reaction Chamber)

Development and application of see-through a-Si solar cells

Preparation and Properties of Amorphous Silicon Produced by a Consecutive, Separated Reaction Chamber Method