It has been a challenge to achieve high efficiency organic photovoltaics (OPV) that absorb long wavelength solar radiation without incurring unacceptable reductions in open circuit voltage (V_(oc)) or charge separatio...
详细信息
ISBN:
(纸本)9781424499663
It has been a challenge to achieve high efficiency organic photovoltaics (OPV) that absorb long wavelength solar radiation without incurring unacceptable reductions in open circuit voltage (V_(oc)) or charge separation efficiency. Based on the parent structure of the 2, 4-bis[4-(N, N-diisobutylamino)-2,6-dihydroxyphenyl] squaraine (SQ), we have increased V_(oc) using a family of highly near-infrared absorbing SQs, achieving values as high as 0.94 V. These SQ donors are: 2, 4-bis[4-(N-Phenyl-1-naphthylamino)-2,6-dihydroxyphenyl] squaraine (1-NPSQ),2,4-bis[4-(N,N-diphenylamino)-2,6 dihydroxyphenyl] squaraine (DPSQ), 2,4-bis[4-(N,N-diphenylamino)-2,6-dihydroxyphenyl] asymmetric squaraine (DPASQ). The spin-cast SQ, 1-NPSQ, DPSQ and DPASQ donors are then coated with the acceptor C_(60) to form bulk heterojunction (BHJ) solar cells that take advantage of their exceptionally high absorption coefficient and nanocrystalline morphology to overcome the short diffusion length characteristic of these materials. Combined with a high short-circuit current density (J_(sc)=10.6 mA/cm~2) and high fill factor (FF=0.64), the optimized 1-NPSQ/C_(60) photovoltaic cells with 1-NPSQ annealed at elevated temperature have a power conversion efficiency of η_p as high as 6.0% (correcting for solar mismatch) at 1 sun (AM 1.5G) simulated solar illumination, which to our knowledge is the highest efficiency reported to date for small molecule OPVs.
Pancreatic adenocarcinoma has a five-year survival rate of only 6%, largely because current diagnostic methods cannot reliably detect the disease in its early stages. Reflectance and fluorescence spectroscopies have t...
详细信息
The PbSe quantum dots‐doped germano‐silica glass fiber was manufactured by using a modified chemical vapor deposition process and the existence of PbSe QDs (∼3.4 nm‐5 nm) was verified by using the TEM and the Rama...
The PbSe quantum dots‐doped germano‐silica glass fiber was manufactured by using a modified chemical vapor deposition process and the existence of PbSe QDs (∼3.4 nm‐5 nm) was verified by using the TEM and the Raman spectrum measurement. The single photon absorption process related peaks appeared at about 882 nm and 1350 nm and two photon absorption process related peaks were observed at about 1022 nm and 1094 nm.
We have investigated the solid nucleation mechanism in laser-quenched Si films on SiO2. Previously neglected experimental steps, consisting of BHF-etching and irradiation in vacuum, were implemented to reduce potentia...
详细信息
The classical Lorentz oscillator model of bound electron motion ordinarily excludes magnetic forces at nonrelativistic intensities for the simple reason that their magnitude is small. However, perturbative and numeric...
详细信息
The classical Lorentz oscillator model of bound electron motion ordinarily excludes magnetic forces at nonrelativistic intensities for the simple reason that their magnitude is small. However, perturbative and numerical results show that when the v⃗×B⃗ term is retained, dynamically enhanced terms give rise to large amplitude, magnetically induced charge displacements at zero frequency and at twice the driving frequency in the Cartesian laboratory frame. Numerical simulations of electron motion are in accord with the predictions of perturbative theory for steady-state motion in the classical picture. Direct integration shows that magnetic response which is comparable to electric dipole response can arise in transparent dielectrics at optical frequencies. Parametric instability in the equations of motion is implicated as the source of rapid energy transfer from electric to magnetic motions by reduction of the equations to a complex Mathieu equation.
We report on a two-week professional development workshop for middle and high school science teachers offered as part of a three-year Indiana Department of Education Math-Science Partnership grant awarded to Rose-Hulm...
详细信息
We report on a two-week professional development workshop for middle and high school science teachers offered as part of a three-year Indiana Department of Education Math-Science Partnership grant awarded to Rose-Hulman Institute of Technology (RHIT) and Vigo County School Corporation (VCSC).
A process, continuous wrapping tantalum barrier, has been developed and investigated in order to reduce the manufacturing cost. By avoiding inserting expensive tantalum tube, a long sheet barrier was directly used to ...
详细信息
A process, continuous wrapping tantalum barrier, has been developed and investigated in order to reduce the manufacturing cost. By avoiding inserting expensive tantalum tube, a long sheet barrier was directly used to wrap a prior restack. In this work, a tantalum barrier with 20 % overlap was wrapped onto sub-elements. Then 18-filament Nb 3 Sn plus 1 copper core restack billet was successfully drawn down and extruded into round wire as thin as a diameter of 0.84 mm. The longitudinal and cross-sectional images revealed most of barriers were continuous and intact. However, further experiments are needed to optimize the process in order to keep the all barriers continuous and intact after manufacturing.
Ni/Al nanostructured multilayer foils were machined with femtosecond pulse-length laser irradiation at various fluences. Scanning electron microscopy, back-scattered electron detection, and atomic force microscopy wer...
Ni/Al nanostructured multilayer foils were machined with femtosecond pulse-length laser irradiation at various fluences. Scanning electron microscopy, back-scattered electron detection, and atomic force microscopy were used to characterize the resulting laser modified regions. We show that material removal at the micron scale is possible with no ignition of a self-propagation reaction emanating from the irradiated areas, a danger minimized by the fact that the extremely short time duration of the pulse produces negligible heat dissipation into the multilayer system. Nevertheless, initial AFM and BSE results give indication that multilayers may be intermixing and reacting locally in areas smaller than the laser beam diameter, though the exact ignition mechanism is still to be determined.
Conducting polyaniline is unique among conducting polymers on account of its excellent optical and electronic properties. The processing of conducting polymers has attracted considerable attention owing to their possi...
Conducting polyaniline is unique among conducting polymers on account of its excellent optical and electronic properties. The processing of conducting polymers has attracted considerable attention owing to their possible application in molecule‐based electronic devices, such as molecular rectifiers, field‐ effect transistors, molecular transducers and sensors. Methods that were applied in this study are addition method (powder), liquid homogeneous method and filtration method. The effects of bonding between methanol and Polyaniline emeraldine base (PANI‐EB) has been investigated. UV‐visible spectrum shows two sharp absorption peaks at 350nm (π‐ π*) and ∼720nm (polaron bands). FTIR spectra proved there is a distinct increase in wave number when PANI‐EB dissolved in methanol which caused by the H‐bonding interaction between PANI‐EB chains and methanol. Thus this make the PANI‐EB molecules change in size that supported by a DLS result. As a conclusion, it indicates that there is interaction between methanol molecules and polyaniline chains.
In electronics and photonics phonons hinder transport or present inefficiency, but here we scrutinized them to improve the photovoltaic solar-cell performance. Phonons account for a significant portion of the temperat...
In electronics and photonics phonons hinder transport or present inefficiency, but here we scrutinized them to improve the photovoltaic solar-cell performance. Phonons account for a significant portion of the temperature-dependent absorption coefficient of a-Si:H (hydrogenated amorphous silicon), e.g., at 300 K, between 1.5 to 2.2 eV. We propose and theoretical treat introduction of suitable a-Si x Sn 1-x alloy, choosing Sn for desired phonons to assist in the absorption of photons and increase the overall efficiency of the cell. Phonons are essentially thermally induced vibrations within the semiconductor lattice. The spectra of these vibrations are characterized by (a) structure and (b) force constant between atoms (inter-atomic potential). Here we show that Sn alloy can be used to enhance phonon-assisted absorption which in turn may increase the current generation.
暂无评论