19 research outputs found
ITO-Free Transparent Organic Solar Cell with Distributed Bragg Reflector for Solar Harvesting Windows
We demonstrated an indium tin oxide (ITO)-free, highly transparent organic solar cell with the potential to be integrated into window panes for energy harvesting purposes. A transparent, conductive ZnO/Ag/ZnO multilayer electrode and a Ag:Ca thin film electrode were used in this transparent device as the bottom and top electrode, respectively. To further improve the transmittance of the solar cell, the thickness of the top ZnO layer was investigated both experimentally and with simulations. An average visible transmittance of \u3e60% was reached, with a maximum transmittance of 73% at 556 nm. Both top and bottom illumination of the solar cell generated comparable power conversion efficiencies, which indicates the wide application of this solar cell structure. In addition, we fabricated distributed Bragg reflector mirrors with sputtered SiO2 and TiO2, which efficiently increased the power conversion efficiency over 20% for the solar cells on glass and poly(ethylene terephthalate) (PET) substrates
Selective quantum Zeno effect of ultracold atom-molecule scattering in dynamic magnetic fields
We demonstrated that final states of ultracold scattering between atom and
molecule can be selectively produced using dynamic magnetic fields of multiple
frequencies. The mechanism of the dynamic magnetic field control is based on a
generalized quantum Zeno effect for the selected scattering channels. In
particular, we use an atom-molecule spin flip scattering to show that the
transition to the selected final spin projection of the molecule in the
inelastic scattering can be suppressed by dynamic modulation of coupling
between the Floquet engineered initial and final states
High Energy Density, Super-Deformable, Garment-Integrated Microsupercapacitors for Powering Wearable Electronics
ITO-Free Transparent Organic Solar Cell with Distributed Bragg Reflector for Solar Harvesting Windows
Transforming Commercial Textiles and Threads into Sewable and Weavable Electric Heaters
We
describe a process
to transform commercial textiles and threads into electric heaters
that can be cut/sewn or woven to fashion lightweight fabric heaters
for local climate control and personal thermal management. Off-the-shelf
fabrics are coated with a 1.5 ÎĽm thick film of a conducting
polymer, polyÂ(3,4-ethylenedioxythiophene), using an improved reactive
vapor deposition method. Changes in the hand feel, weight, and breathability
of the textiles after the coating process are imperceptible. The resulting
fabric electrodes possess competitively low sheet resistancesî—¸44
Ω/□ measured for coated bast fiber textiles and 61 Ω/□
measured for coated cotton textilesî—¸and act as low-power-consuming
Joule heating elements. The electrothermal response of the textile
electrodes remain unaffected after cutting and sewing due to the robustness
of the conductive coating. Coated, conductive cotton yarns can also
be plain-woven into a monolithic fabric heater. A demonstrative circuit
design for a soft, lightweight, and breathable thermal glove is provided
Experimental and simulation analysis of bubble deformation in foaming polypropylene
This paper investigates the bubble deformation in bubble growth using a self-made in situ visual injection molding device. The results show that the deformation degree of independent bubbles is kept within 0.015. Under the frame rate of 25 frames per second (FPS), it is found that adjacent bubbles with the same average diameter simultaneously pass through the deformation critical point, while adjacent bubbles with different average diameters can’t pass through the critical deformation point at the same time. The interaction in the process of adjacent bubble growth is simulated by finite element software, radial migration of bubbles is suppressed, the hoop stretch of bubbles is enhanced, and the deformation sequence of adjacent bubbles is determined by bubble radius and bubble pressure. On the basis of the bubble influence zone model and the bubble deformation model, a bubble deformation response model is established, used to reflect adjacent bubbles’ deformation response speed
Molecular Orientation-Dependent Interfacial Energetics and Built-in Voltage Tuned by a Template Graphene Monolayer
Highly transparent and conductive
monolayer graphene was used as a template to tune
the crystal orientation of pentacene from generic standing-up (001)
to lying-down (022) in neat films. Spatially resolved Kelvin probe
force microscopy (KPFM) was used to reveal the energy levels of pentacene
thin films grown on substrates with and without the template graphene
layer, as well as the energy level alignment in various pentacene-containing
organic–organic heterojunctions. A correlation between crystal
domain orientation and the work function was directly observed using
KPFM. Up to 0.36 eV shifts in work function were observed in neat
pentacene films over large areas (>0.5 in.<sup>2</sup>) upon orientation
transition, likely due to the transition from Fermi level pinning
(standing-up pentacene on ITO) to vacuum level alignment (lying-down
pentacene on graphene–ITO). Morphology-induced energy level
shifts versus interfacial electronic equilibration effects were disentangled
using atomic force microscopy, KPFM, X-ray diffraction, and Raman
data for neat pentacene films and pentacene containing heterojunctions
on monolayer graphene. The data detailed herein provide a fundamental
picture of the major interfacial effects active in optoelectronic
devices containing a bare graphene electrode