Abstract We report the growth and characterization of record‐efficiency ZnO/CdS/CuInGaSe 2 thin‐film solar cells. Conversion efficiencies exceeding 19% have been achieved for first time, this result indicates that 20% goal is within reach. Details experimental procedures are provided, material device data presented. Published in 2003 by John Wiley & Sons, Ltd.

A photovoltaic conversion efficiency of 40.8% at 326 suns concentration is demonstrated in a monolithically grown, triple-junction III–V solar cell structure which each active junction composed an alloy with different lattice constant chosen to maximize the theoretical efficiency. The semiconductor was grown by organometallic vapor phase epitaxy inverted configuration 1.83 eV Ga.51In.49P top lattice-matched GaAs substrate, metamorphic 1.34 In.04Ga.96As middle junction, and 0.89 In.37Ga.63As...

The authors demonstrate a thin, Ge-free III–V semiconductor triple-junction solar cell device structure that achieved 33.8%, 30.6%, and 38.9% efficiencies under the standard 1sun global spectrum, space concentrated direct spectrum at 81suns, respectively. consists of 1.8eV Ga0.5In0.5P, 1.4eV GaAs, 1.0eV In0.3Ga0.7As p-n junctions grown monolithically in an inverted configuration on GaAs substrates by organometallic vapor phase epitaxy. lattice-mismatched junction was last graded GaxIn1−xP...

The self-absorption of radiated photons increases the minority carrier concentration in semiconductor optoelectronic devices such as solar cells. This so-called photon recycling leads to an increase external luminescent efficiency, fraction internally that are able escape through front surface. An increased efficiency turn correlates with open-circuit voltage and ultimately conversion efficiency. We develop a detailed ray-optical model calculates Voc for real, non-idealized cells, accounting...

A link between urban living and disease is seen in recent historical records, but the presence of this association prehistory has been difficult to assess. If transition does result an increase disease-based mortality, we might expect see evidence increased resistance longer-term urbanized populations, as natural selection. To test this, determined frequency allele (SLC11A1 1729 + 55del4) associated with intracellular pathogens such tuberculosis leprosy. We found a highly significantly...

We present results for quadruple-junction inverted metamorphic (4J-IMM) devices under the concentrated direct spectrum and analyze limitations to performance. The integrate lattice-matched subcells with rear heterojunctions, as well lattice-mismatched low threading dislocation density. To interconnect subcells, thermally stable tunnel junctions are used, a GaAsSb/GaInAs junction between subcells. A broadband antireflection coating is front metal grid designed high concentration operation....

The inverted metamorphic solar cell has highly tunable bandgaps, in part due to the subcells. Using phosphide-based compositionally graded buffers, we show a wide variety of GaInAs cells, ranging bandgap from 1.2 0.7 eV. These subcells are all high quality and can be used for multijunction designs. cells with 0.70 eV bandgaps developed using an InAsP buffer that extends beyond InP lattice constant, allowing access additional 2 mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Single-wall carbon nanotube (SWCNT) networks form a highly transparent and electrically conductive thin film that can be used to replace traditional conducting oxides (TCOs) in variety of applications. Here, the authors demonstrate their use as back contact near-infrared (NIR) CdTe solar cell. SWCNT are hole-selective conductors have significantly greater NIR transparency than TCOs—qualities which could both make them very useful tandem thin-film cells. incorporated into single-junction...

Efficient crystalline silicon heterojunction solar cells are fabricated on p-type wafers using amorphous emitter and back contact layers. The independently confirmed AM1.5 conversion efficiencies 19.3% a float-zone wafer 18.8% Czochralski wafer; show no significant light-induced degradation. best open-circuit voltage is above 700 mV. Surface cleaning passivation play important roles in cell performance.

For solar cells dominated by radiative recombination, the performance can be significantly enhanced improving internal optics. We demonstrate a detailed model for that calculates external luminescent efficiency and discuss relationship between luminescence. The accounts wavelength-dependent optical properties in each layer, parasitic electrical losses, multiple reflections within cell, assumes isotropic emission. single-junction cells, calculation leads to V <sub...

The formation chemistry and growth dynamics of thin-film CuInSe2 grown by physical vapor deposition have been considered along the reaction path leading from CuxSe:CuInSe2 two-phase region to single-phase CuInSe2. (Cu2Se)β(CuInSe2)1−β (0&amp;lt;β≤1) mixed-phase precursor is created in a manner consistent with liquid-phase assisted process. At substrate temperatures above 500 °C presence excess Se, film structure columnar through thickness column diameters range 2.0–5.0 μm. Films deposited on...

Abstract We report the growth and characterization of improved efficiency wide‐bandgap ZnO/CdS/CuGaSe 2 thin‐film solar cells. The CuGaSe absorber thickness was intentionally decreased to better match depletion widths indicated by drive‐level capacitance profiling data. A total‐area 9·5% achieved with a fill factor 70·8% V oc 910 mV. Published in 2003 John Wiley &amp; Sons, Ltd.

AlGaInP solar cells with bandgaps between 1.9 and 2.2 eV are investigated for use in next-generation multijunction photovoltaic devices. This quaternary alloy is of great importance to the development III-V five or more junctions optimized operation at elevated temperatures because high required these designs. In this work, we explore conditions organometallic vapor-phase epitaxy growth study their effects on cell performance. Initial efforts focused developing ~2.0-eV a nominal aluminum...

We discuss lattice-mismatched (LMM) approaches utilizing compositionally step-graded layers and buffer that yield III-V photovoltaic devices with performance parameters equaling those of similar lattice-matched (LM) devices. Our progress in developing high-performance, LMM, InP-based GaInAs/InAsP materials for thermophotovoltaic (TPV) energy conversion is highlighted. A novel, monolithic, multi-bandgap, tandem device solar PV (SPV) involving LMM also presented along promising preliminary results.

Abstract Designing a tandem solar cell for use in concentrator system is challenging because: (a) the conditions are variable, so cells rarely operate under optimal conditions, and (b) not controlled, any design problems difficult to characterize. Here, we show how fill factor can be used as diagnostic tool either verify correct operation or help identify problem. We give particular attention detection of spectral skewing by optics, this reduce performance GaInP 2 /GaAs The conclusions...

Abstract To fabricate a high‐efficiency polycrystalline thin‐film tandem cell, the most critical work is to make top cell ( &gt; 15%) with high bandgap (E g = 1·5–1·8 eV) and transmission (T 70%) in near‐infrared (NIR) wavelength region. The CdTe one of candidates for because state‐of‐the‐art single‐junction devices efficiencies more than 16% are available, although its (1·48 slightly lower current‐matched dual‐junction device. In this paper, we focus on development a: (1) thin, low‐bandgap...

Abstract We describe the design and performance of a three‐terminal tandem solar cell for low‐concentration terrestrial applications. Designed operation under GaAs filter, demonstrates cumulative conversion efficiencies 10.2 11.9% at 1 sun 45 suns, respectively, concentrated direct spectrum. The middle terminal is shared between two subcells allows them to be operated independently their respective maximum power points. Copyright © 2009 John Wiley &amp; Sons, Ltd.

The performance of 2-μm-thick crystal silicon (c-Si) solar cells grown epitaxially on heavily doped wafer substrates is quantitatively linked to absorber dislocation density. We find that such thin devices have a high tolerance bulk impurities compared wafer-based cells. minority carrier diffusion length about half the spacing and must be roughly three times thickness for efficient extraction. Together, modeling experimental results provide design guidelines film c-Si photovoltaic

The inverted metamorphic multijunction (IMM) solar cell has demonstrated efficiencies as high 40.8% at 25°C and 326 suns concentration. actual operating temperature in a commercial module, however, is likely to be much 50-70°C hotter, reaching 100°C. In order able evaluate the performance under these real-world conditions, we have measured open-circuit voltage, short-circuit current density efficiency temperatures up 125°C concentrations 1000 suns, well coefficients of parameters. Spectral...

Multijunction solar cells can be fabricated by mechanically bonding together component that are grown separately. Here, we present four-junction four-terminal mechanical stacks composed of GaInP/GaAs tandems on GaAs substrates and GaInAsP/GaInAs InP substrates. The were bonded with a low-index transparent epoxy acts as an angularly selective reflector to the bandedge luminescence, while simultaneously transmitting nearly all subbandgap light. As determined electroluminescence measurements...