A dynamic-inner LSTM prediction method for key alarm variables forecasting in chemical process

With the increase in the complexity of industrial system, simply detecting and diagnosing a fault may be insufficient in some cases, and prognosing the fault ahead of time could have a certain necessity. Accurate prediction of key alarm variables in chemical process can indicate the possible change to reduce the probability of abnormal conditions. According to the characteristics of chemical process data, this work proposed a key alarm variables prediction model in chemical process based on dynamic-inner principal component analysis(DiPCA) and long short-term memory(LSTM). DiPCA is used to extract the most dynamic components for prediction. While LSTM is used to learn the relationship and predict the key alarm variables. This work used a simulation data set and a real hydrogenation process data set for applications and explained the model validity from the essential characteristics. Comparison of results with different models shows that our model has better prediction accuracy and performance, which can provide the basis for fault prognosis and health management.

Ternary blend strategy in benzotriazole-based organic photovoltaics for indoor application

Organic photovoltaics(OPVs)suitable for application in indoor lighting environments can power a wide range of internet of things(Io T)related electronic devices.The ternary structure has huge advantages in improving the photovoltaic performance of OPVs,including broadening the light absorption,improving the charge transport,manipulating the energy loss(E_(loss))and so on.Herein,we use wide-bandgap photo-active materials,including the benzotriazole-based polymer donor(J52-F),chlorinated polymer donor(PM7)and A_(2)-A_1-D-A_1-A_(2)-structured acceptor(BTA3),to construct ternary OPVs for indoor light applications.Benefitting from the introduction of PM7 as the third component in J52-F:BTA3-based blend,a gratifying PCE of 20.04%with a high V_(OC)of 1.00 V can be obtained under the test conditions with an illumination of 300 lx from an LED lighting source with a color temperature of 3000 K.The excellent device performance is inseparable from the matched spectrum,enhanced light absorption and the reduced E_(loss),while the improved charge transport capability and suppression of carrier recombination also play an indelible role.Our work shows a potential material system to meet the requirement of devices applied under indoor light.Moreover,these findings demonstrate that designing multi-component OPVs is indeed a feasible way to further improve the performances of the photovoltaic energy conversion system for indoor applications.

Correlated perovskite nickelates with valence variable rare-earth compositions

While the metal to insulator transition(MIT)of d-band correlated perovskite nickelates(RENiO_(3))are widely adjustable via their rare-earth composition,the roles of potential valence variabilities associated with the rare-earth elements were rarely concerned.Herein,we demonstrate the material synthesis and MIT properties of RENiO_(3) containing valence variable rare-earth compositions,such as Ce,Pr,Sm,Eu and Tb.The metastable perovskite structure of SmNiO_(3) and EuNiO_(3) with a rare-earth valence states variable towards+2 can be effectively synthesized under high oxygen pressures as it is necessary to reduce their formation free energies.This is in contrast to Ce and Tb,in which situations the variable rare-earth valence state towards+4 reduces their ionic radius and prohibits their occupation or co-occupation of the rare-earth site within the perovskite structured RENiO_(3).Nevertheless,PrNiO_(3) with MIT properties can be effectively synthesized at lower oxygen pressures,owing to the higher stability to form a fully occupied 6s orbit associated Pr3+compared to the half-filled one related to Pr4+.The present work provides guidance for regulating the MIT properties of RENiO_(3).

Printable SnO2 cathode interlayer with up to 500 nm thickness-tolerance for high-performance and large-area organic solar cells

The printable electrode interlayer with excellent thickness tolerance is crucial for mass production of organic solar cells(OSCs)by solution-based print techniques. Herein, high-quality printable SnO2 films are simply fabricated by spin-coating or bladecoating the chemical precipitated SnO2 colloid precursor with post thermal annealing treatment. The SnO2 films possess outstanding optical and electrical properties, especially extreme thickness-insensitivity. The interfacial electron trap density of SnO2 cathode interlayers(CILs) are very low and show negligible increase as the thicknesses increase from 10 to 160 nm,resulting in slight change of the power conversion efficiencies(PCEs) of the PM6:Y6 based OSCs from 16.10% to 13.07%. For blade-coated SnO2 CIL, the PCE remains high up to 12.08% even the thickness of SnO2 CIL is high up to 530 nm. More strikingly, the large-area OSCs of 100 mm2 with printed SnO2 CILs obtain a high efficiency of 12.74%. To the best of our knowledge, this work presents the first example for the high-performance and large-area OSCs with the thickness-insensitive SnO2 CIL.

Solution-Processed Titanium Chelate Used as Both Electrode Modification Layer and Intermediate Layer for Efficient Inverted Tandem Polymer Solar Cells

ABSTRACT Organic polymer solar cells （PSCs） have attracted increasing attention due to light weight, low cost, flexibility and roll-to-roll manufacturing. However, the limited light harvest range of the photoactive layer greatly restrains the power conversion efficiency （PCE） enhancement. In order to expand the light absorption range and further enhance the PCE of the PSCs, tandem structures have been designed and demonstrated. In tandem solar cell, the intermediate layer （IML） plays a critical role in physically and electrically connection of the two subcells. Herein, we apply titanium （diisopropoxide） bis（2,4-pentanedionate） （TIPD） as both electrode modification layer and intermediate layer to investigate the feasibility in inverted tandem polymer solar cells. The same photoactive layers of PTB7-Th：PC71BM are adopted in both front and rear subcells to simplify the evaluation of effectiveness of TIPD layer in tandem structures. By modulating the treatment condition of IML and the thickness of photoactive layer, efficient inverted tandem PSCs have been achieved with minimized voltage loss and excellent charge transportation, giving a best Voc of 1.54 V, which is almost two times that of the single bulk heterojunction （BHJ）-PSC （0.78 V） and an enhanced PCE up to 8.11%.

1.3 μm InAs/GaAs quantum dot lasers on silicon with GaInP upper cladding layers

We report on the first electrically pumped continuous-wave(CW) In As/Ga As quantum dot(QD) laser grown on Si with a GaInP upper cladding layer. A QD laser structure with a Ga_(0.51)In_(0.49)P upper cladding layer and an Al_(0.53)Ga_(0.47)As lower cladding layer was directly grown on Si by metal–organic chemical vapor deposition. It demonstrates the postgrowth annealing effect on the QDs was relieved enough with the GaInP upper cladding layer grown at a low temperature of 550°C. Broad-stripe edge-emitting lasers with 2-mm cavity length and 15-μm stripe width were fabricated and characterized. Under CW operation, room-temperature lasing at ~1.3 μm has been achieved with a threshold density of 737 A∕cm^2 and a single-facet output power of 21.8 mW.

Recent Advances of Monolithic All-Perovskite Tandem Solar Cells:From Materials to Devices

Organic-inorganic metal-halide perovskite solar cells(PerSCs)have achieved significant progresses due to their outstanding optoelectronic charac-teristics,and the power conversion efficiency(PCE)of single-junction PerSCs has been boosted from 3.8%to a certified 25.2%.However,the efficien-cy of single-junction cells is governed by the Shockley-Queisser(S-Q)radiative limit,and fabricating all-perovskite tandem solar cells is a particularly attractive method to break the S-Q limit.Since the bandgap of lead(Pb)-based mixed halide perovskite can be tuned from 1.55 eV to 2.3 eV,and the mixed tin(Sn)-Pb perovskites have bandgap of~1.2 eV,these perovskites become the best candidates for the front and rear subcells of all-perovskite tandem device,respectively.In this review,we firstly summarize the current development progresses of two-terminal(2-T)all-perovskite tandem so-lar cells.For further optimizing the device performance,the wide bandgap mixed halide perovskites for front subcell,mixed Sn-Pb narrow bandgap perovskites for rear subcell,and the interconnection layer(ICL)of 2-T tandem device are then discussed.This review aims to open a pathway to real-ize highly efficient all-perovskite tandem solar cells.

Efficient organic solar cells with low-temperature in situ prepared Ga_(2)O_(3) or In_(2)O_(3) electron collection layers

Facile synthesis of an interfacial layer in organic solar cells (OSCs) is important for broadening material designs and upscaling photovoltaic conversion efficiency (PCE).Herein,a mild solution process of spin-coating In(acac)3and Ga(acac)3isopropanol precursors followed by low-temperature thermal treatment was developed to fabricate In_(2)O_(3)and Ga2O3cathode buffer layers (CBLs).The introduction of In_(2)O_(3)or Ga2O3CBLs endows PM6:Y6-based OSCs with outstanding performance and high PCEs of 16.17%and 16.01%,respectively.Comparison studies present that the In_(2)O_(3)layer possesses a work function (WF) of 4.58 eV,which is more favorable for the formation of ohmic contact compared with the Ga2O3layer with a WF of 5.06 eV and leads to a higher open circuit voltage for the former devices.Electrochemical impedance spectroscopy was performed to reveal how In_(2)O_(3)and Ga2O3affect the internal charge transfer and the origin of their performance difference.Although In_(2)O_(3)possesses lower series resistance loss,Ga2O3has a higher recombination resistance,which enhances the device fill factor and compensates for its series resistance loss to some extent.Comparative analysis of the photo-physics of In_(2)O_(3)and Ga2O3suggests that both are excellent CBLs for highly efficient OSCs.

Size-Controllable Metal Chelates as Both Light Scattering Centers and Electron Collection Layer for High-Performance Polymer Solar Cells

An electron collection layer(ECL)between a photoactive overlay and an electrode plays a crucial role in optimizing the light field and charge extraction in bulk-heterojunction(BHJ)polymer solar cells(PSCs).However,the typical thickness of the photoactive layer is thinner than its optical path lengths,limiting further improvement of light absorption and device performance.