scholarly journals Intrinsically Stable Wide Band Gap Br-Free CsxFA1-xPbI3 (x=0.5-0.9) Perovskites Overcoming Phase Segregation

2020 ◽  
Author(s):  
Xingtao Wang ◽  
Yuetian Chen ◽  
Taiyang Zhang ◽  
Yong Wang ◽  
Miao Kan ◽  
...  
Keyword(s):  
Precursor Solution ◽  
Phase Segregation ◽  
Wide Band ◽  
Contact Layer ◽  
Hole Transport ◽  
Precursor Film ◽  
Wide Band Gap ◽  
Thermal Evaporator ◽  
20 Nm ◽  
Butanol Solution

<p>A ~20 nm thick compact TiO<sub>2</sub> was deposited on patterned FTO (TEC-7) by spray pyrolysis of 0.2 M Ti (IV) bis(ethylacetoacetate)-diisopropoxide 1-butanol solution at 450 ºC followed by annealing at 450 ºC for one hour. The perovskite precursor solution was prepared by dissolving CsI, FAI, PbI<sub>2</sub> and DMAI in 1 mL DMF and was deposited on 70 ℃ preheated c-TiO<sub>2</sub>/FTO substrate by spin coating at 3000 rpm for 30 s. The obtained precursor film was annealed at 170℃ for 40 min. A hole-transport material (HTM) solution containing 0.1 M spiro-OMeTAD, 0.035 M Li-TFSi, and 0.12 M 4-tert-butylpyridine (tBP) in chlorobenzene solution was then spin coated onto the perovskite film at 4000 rpm for 20 s. Finally, a 100 nm thick Ag was deposited as contact layer via thermal evaporator.</p>

scholarly journals Intrinsically Stable Wide Band Gap Br-Free CsxFA1-xPbI3 (x=0.5-0.9) Perovskites Overcoming Phase Segregation

2020 ◽  
Author(s):  
Xingtao Wang ◽  
Yuetian Chen ◽  
Taiyang Zhang ◽  
Yong Wang ◽  
Miao Kan ◽  
...  
Keyword(s):  
Precursor Solution ◽  
Phase Segregation ◽  
Wide Band ◽  
Contact Layer ◽  
Hole Transport ◽  
Precursor Film ◽  
Wide Band Gap ◽  
Thermal Evaporator ◽  
20 Nm ◽  
Butanol Solution

<p>A ~20 nm thick compact TiO<sub>2</sub> was deposited on patterned FTO (TEC-7) by spray pyrolysis of 0.2 M Ti (IV) bis(ethylacetoacetate)-diisopropoxide 1-butanol solution at 450 ºC followed by annealing at 450 ºC for one hour. The perovskite precursor solution was prepared by dissolving CsI, FAI, PbI<sub>2</sub> and DMAI in 1 mL DMF and was deposited on 70 ℃ preheated c-TiO<sub>2</sub>/FTO substrate by spin coating at 3000 rpm for 30 s. The obtained precursor film was annealed at 170℃ for 40 min. A hole-transport material (HTM) solution containing 0.1 M spiro-OMeTAD, 0.035 M Li-TFSi, and 0.12 M 4-tert-butylpyridine (tBP) in chlorobenzene solution was then spin coated onto the perovskite film at 4000 rpm for 20 s. Finally, a 100 nm thick Ag was deposited as contact layer via thermal evaporator.</p>

scholarly journals Compositional Engineering for Efficient Wide Band Gap Perovskites with Improved Stability to Photoinduced Phase Segregation

2018 ◽  
Vol 3 (2) ◽  
pp. 428-435 ◽  
Author(s):  
Kevin A. Bush ◽  
Kyle Frohna ◽  
Rohit Prasanna ◽  
Rachel E. Beal ◽  
Tomas Leijtens ◽  
...  
Keyword(s):  
Band Gap ◽  
Phase Segregation ◽  
Wide Band ◽  
Wide Band Gap ◽  
Improved Stability

Process Characterization of Ultra-fine Tin Oxide Fibers Synthesis

2006 ◽  
Vol 951 ◽  
Author(s):  
Yu Wang ◽  
Idalia Ramos ◽  
Jorge J. Santiago-Avilés
Keyword(s):  
Tin Oxide ◽  
Precursor Solution ◽  
Wide Band ◽  
X Ray Diffraction ◽  
Wide Band Gap ◽  
Rutile Structure ◽  
Sensor Applications ◽  
Process Characterization ◽  
Poly Ethylene ◽  
Physical Changes

ABSTRACTTin oxide (SnO2) with rutile structure is a wide-band gap semiconductor that has been used extensively in optoelectronic devices and sensors. A fibrous shape is especially favorable for the sensor applications. The authors synthesized micro-/nano- SnO2 fibers from a precursor solution of poly (ethylene oxide) (PEO), chloroform (CHCl3) and dimethyldineodecanoate tin (C22H44O4Sn) using electrospinning and metallorganics decomposition techniques. This paper uses Fourier-transform infrared spectroscopy, thermogravimetric and differential thermal analysis, and x-ray diffraction to reveal a series of chemical and physical changes from the starting chemicals to the final product of ultra-fine SnO2 fibers: the solvent CHCl3 evaporates during the electrospinning; the organic groups in PEO and C22H44O4Sn decompose with Sn-C bond in C22H44O4Sn replaced by Sn-O between 220 and 300°C, and transform into rutile structure between 300 and 380°C; the incipient rutile lattice develops into a relatively complete degree after sintering at higher temperatures up to 600°C.

Triple-halide wide–band gap perovskites with suppressed phase segregation for efficient tandems

Science ◽  
2020 ◽  
Vol 367 (6482) ◽  
pp. 1097-1104 ◽  
Author(s):  
Jixian Xu ◽  
Caleb C. Boyd ◽  
Zhengshan J. Yu ◽  
Axel F. Palmstrom ◽  
Daniel J. Witter ◽  
...  
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Low Cost ◽  
Perovskite Solar Cells ◽  
Phase Segregation ◽  
Wide Band ◽  
Charge Carrier Mobility ◽  
Lattice Parameter ◽  
Open Circuit ◽  
Wide Band Gap

Wide–band gap metal halide perovskites are promising semiconductors to pair with silicon in tandem solar cells to pursue the goal of achieving power conversion efficiency (PCE) greater than 30% at low cost. However, wide–band gap perovskite solar cells have been fundamentally limited by photoinduced phase segregation and low open-circuit voltage. We report efficient 1.67–electron volt wide–band gap perovskite top cells using triple-halide alloys (chlorine, bromine, iodine) to tailor the band gap and stabilize the semiconductor under illumination. We show a factor of 2 increase in photocarrier lifetime and charge-carrier mobility that resulted from enhancing the solubility of chlorine by replacing some of the iodine with bromine to shrink the lattice parameter. We observed a suppression of light-induced phase segregation in films even at 100-sun illumination intensity and less than 4% degradation in semitransparent top cells after 1000 hours of maximum power point (MPP) operation at 60°C. By integrating these top cells with silicon bottom cells, we achieved a PCE of 27% in two-terminal monolithic tandems with an area of 1 square centimeter.

TEM and cathodoluminescence of precipitates in II-VI semiconductors

1988 ◽  
Vol 46 ◽  
pp. 488-489
Author(s):  
Joanna L. Batstone
Keyword(s):  
Crystal Growth ◽  
Band Gap ◽  
Local Strain ◽  
Wide Band ◽  
Optoelectronic Device ◽  
Wide Band Gap ◽  
Bulk Crystal Growth ◽  
Transmission Electron ◽  
Device Applications ◽  
Stoichiometry Control

Interest in II-VI semiconductors centres around optoelectronic device applications. The wide band gap II-VI semiconductors such as ZnS, ZnSe and ZnTe have been used in lasers and electroluminescent displays yielding room temperature blue luminescence. The narrow gap II-VI semiconductors such as CdTe and HgxCd1-x Te are currently used for infrared detectors, where the band gap can be varied continuously by changing the alloy composition x.Two major sources of precipitation can be identified in II-VI materials; (i) dopant introduction leading to local variations in concentration and subsequent precipitation and (ii) Te precipitation in ZnTe, CdTe and HgCdTe due to native point defects which arise from problems associated with stoichiometry control during crystal growth. Precipitation is observed in both bulk crystal growth and epitaxial growth and is frequently associated with segregation and precipitation at dislocations and grain boundaries. Precipitation has been observed using transmission electron microscopy (TEM) which is sensitive to local strain fields around inclusions.

Electron microscopic characterization of diamond thin films and substrates for diamond heteroepitaxial growth

1989 ◽  
Vol 47 ◽  
pp. 592-593
Author(s):  
J.B. Posthill ◽  
R.P. Burns ◽  
R.A. Rudder ◽  
Y.H. Lee ◽  
R.J. Markunas ◽  
...  
Keyword(s):  
Thin Films ◽  
Wide Band ◽  
Deposition Process ◽  
Heteroepitaxial Growth ◽  
Electron Microscopic ◽  
Wide Band Gap ◽  
Lattice Matching ◽  
Different Types ◽  
Diamond Thin Films

Because of diamond’s wide band gap, high thermal conductivity, high breakdown voltage and high radiation resistance, there is a growing interest in developing diamond-based devices for several new and demanding electronic applications. In developing this technology, there are several new challenges to be overcome. Much of our effort has been directed at developing a diamond deposition process that will permit controlled, epitaxial growth. Also, because of cost and size considerations, it is mandatory that a non-native substrate be developed for heteroepitaxial nucleation and growth of diamond thin films. To this end, we are currently investigating the use of Ni single crystals on which different types of epitaxial metals are grown by molecular beam epitaxy (MBE) for lattice matching to diamond as well as surface chemistry modification. This contribution reports briefly on our microscopic observations that are integral to these endeavors.

Wide Band-Gap Kesterite Thin Films for Photovoltaic Applications

2018 ◽  
Author(s):  
Raquel Caballero ◽  
Leonor de la Cueva ◽  
Andrea Ruiz-Perona ◽  
Yudenia Sánchez ◽  
Markus Neuschitzer ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Wide Band ◽  
Wide Band Gap ◽  
Photovoltaic Applications
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