Interfacial Voids Trigger Carbon-Based, All-Inorganic Cs Pb IBr2 Perovskite Solar Cells with Photovoltage Exceeding 1.33 V

A novel interface design is proposed for carbon-based,all-inorganic CsPbIBr2 perovskite solar cells(PSCs)by introducing interfacial voids between TiO2 electron transport layer and CsPbIBr2 absorber.Compared with the general interfacial engineering strategies,this design exempts any extra modification layer in final PSC.More importantly,the interfacial voids produced by thermal decomposition of 2-phenylethylammonium iodide trigger three beneficial e ects.First,they promote the light scattering in CsPbIBr2 film and thereby boost absorption ability of the resulting CsPbIBr2 PSCs.Second,they suppress recombination of charge carriers and thus reduce dark saturation current density(J0)of the PSCs.Third,interfacial voids enlarge built-in potential(Vbi)of the PSCs,awarding increased driving force for dissociating photo-generated charge carriers.Consequently,the PSC yields the optimized e ciency of 10.20%coupled with an open-circuit voltage(Voc)of 1.338 V.The Voc achieved herein represents the best value among CsPbIBr2 PSCs reported earlier.Meanwhile,the non-encapsulated PSCs exhibit an excellent stability against light,thermal,and humidity stresses,since it remains^97%or^94%of its initial e ciency after being heated at 85℃for 12 h or stored in ambient atmosphere with relative humidity of 30–40%for 60 days,respectively.

Sea urchin‐like NiMoO_(4) nanorod arrays as highly efficient bifunctional catalysts for electrocatalytic/photovoltage‐driven urea electrolysis

Developing multifunctional electrocatalysts with high catalytic activity,longterm stability,and low cost is essential for electrocatalytic energy conversion.Herein,sea urchinlike NiMoO_(4) nanorod arrays grown on nickel foam has been developed as a bifunctional electrocatalyst for urea oxidation and hydrogen evolution.The NiMoO_(4)‐200/NF catalyst exhibits efficient activity toward hydrogen evolution reaction with a low overpotential of only 68 mV in 1.0 mol/L KOH to gain a current density of 10 mA cm^(–2).The NiMoO_(4)‐300/NF catalyst exhibits a prominent oxygen evolution reaction(OER)catalytic activity with an overpotential of 288 mV at 50 mA cm^(–2),as well as for urea oxidation reaction with an ultralow potential of 1.36 V at 10 mA cm^(–2).The observed difference in electrocatalytic activity and selectivity,derived by temperature variation,is ascribed to different lattice oxygen contents.The lattice oxygen of NiMoO_(4)‐300/NF is more than that of NiMoO_(4)‐200/NF,and the lattice oxygen is conducive to the progress of OER.A urea electrolyzer was assembled with Ni‐MoO_(4)‐200/NF and NiMoO_(4)‐300/NF as cathode and anode respectively,delivering a current density of 10 mA cm^(–2)at a cell voltage of merely 1.38 V.The NiMoO_(4)nanorod arrays has also been successfully applied for photovoltage‐driven urea electrolysis and hydrogen production,revealing its great potential for solar‐driven energy conversion.

Angle-sensitive and fast photovoltage of silver nanocluster embeded ZnO thin films induced by 1.064-μm pulsed laser

Silver nanocluster embedded ZnO composite thin film was observed to have an angle-sensitive and fast photovoltaic effect in the angle range from -90° to 90° , its peak value and the polarity varied regularly with the angle of incidence of the 1.064-μm pulsed Nd：YAG laser radiation onto the ZnO surface. Meanwhile, for each photovoltaic signal, its rising time reached -2 ns with an open-circuit photovoltage of -2 ns full width at half-maximum. This angle-sensitive fast photovoltaic effect is expected to put this composite film a candidate for angle-sensitive and fast photodetector.

Study on the Surface Photovoltage and Fluorescence Properties of N, N-Bis(4-aminopheny)-1, 4 quinonenediimine Doped with H_4SiW_(12)O_(40)

Aniline oligomer composite materials using heteropolyacid H4SiW12O40 as dopant was synthesized, and the effect of the doping concentration on the photoluminescence and surface photovoltaic properties were investigated.

STUDIES OF SURFACE PHOTOVOLTAGE PROPERTIES AND CHARGE TRANSFER ON TRANSITION METAL PORPHYRIN COMPLEX （Ⅰ）

Photovoltage properties and charge transfer process of tailed porpbyrin Mn(Ⅲ) complex. meso-mono-|o-(4-diethylamino) butyramidophenyl| triphenyl porphyrin Mn(Ⅲ) (MDBPTPPMn(Ⅲ)Cl) were investigated by surface photovoltage spectrum (SPS)and field modulation surface photovoltage spectrum (FMSPS). Furthermore, its absorption spectra in near-ultraviolet and near-infrared that have been disputed are given a new assignment in this paper.

Photovoltage analysis of a heterojunction solar cell

According to the p n junction model of Shockley, the relationship between the equilibrium carrier concentrations of n-type and p-type semiconductors on the edges of the depletion region of a p-n junction solar cell is analysed. The calculation results show that the photovoltage can exceed the built-in voltage for a special kind of heterojunction solar cell. When the photovoltage exceeds the built-in voltage under illumination, the dark current and the photocurrent are impeded by the peak of voltage barrier at the interface and the expression of the total I-V characteristic is given.

The Photovoltage-gas Sensitive Properties of 7,7,8,8-Tetracyanoquinodimethane(TCNQ)

In this paper, surface photovoltage technique (SPV) was applied to the study of photovoltaic and gas sensitive properties of TCNQ polycrystal. It was found that SPV shows two peaks at 390 nm(P1) and 480 nm (P2) in the ultraviolet-visible range. And they are opposite in phase. The results of gaseous adsorption confirm that P, shows the acceptor characteristics, while PI shows that of donor. During adsorption, donor gas interacts with conjugated II * orbital, acceptor gas with the terminal group C=N .

A Study on Synthesis and Surface Photovoltage Spectrum of Palladium Tetraethyl-tetramethylporphyrin and Feasilibity of Phosphorescence Manometry

A static optical pressure measurement system and the synthesis of Palladium tetraethyl tetramethyl porphyrin(PdTETMP) are investigated in this paper. UV visible spectrum, surface photovoltage spectrum of PdTETMP and oxygen quenching phosphorescence of PdTETMP are determined. The results indicate that the photovoltaic respons of PdTETMP decrease as the partial pressure of oxygen rises, which is similar to oxgyen quenching of the phosphorescence of PdTETMP. The data shows, as predicted by Stem Volmer relationship I 0/I=A+Bp/p 0, that a nearly linear relationship between I 0/I versus p/p 0 and the intercept A and slope B are 0.32, 0.67, respectively.

Vacuum Sensitivity of Photovoltage of AlGaAs/GaAsMultiple Quantum Wells

Abstract: The photovoltage spectra of AlGaAs/GaAs multiple quantum wells at different vacuum have been measured and the vacuum sensitivity of photovoltage is re-ported. The experimental results show that the photovoltage decreases in a step - like manner at 105 Pa and increases in a sept - like manner at 0.1 Pa. It is believed that the variation of photovoltage with vacuum is due to the action of oxygen atoms adsorbing at the surface of AlGaAs/GaAs multiple quantum wells structure.

In-situ transient photovoltage study on interface electron transfer regulation of carbon dots/NiCo_(2)O_(4) photocatalyst for the enhanced overall water splitting activity

Photocatalytic hydrogen production by overall water solar-splitting is a prospective strategy to solve energy crisis.However,the rapid recombination of photogenerated electron–hole pairs deeply restricts photocatalytic activity of catalysts.Here,the in-situ transient photovoltage(TPV)technique was developed to investigate the interfacial photogenerated carrier extraction,photogenerated carrier recombination and the interfacial electron delivery kinetics of the photocatalyst.The carbon dots/NiCo_(2)O_(4)(CDs/NiCo_(2)O_(4))composite shows weakened recombination rate of photogenerated carriers due to charge storage of CDs,which enhances the photocatalytic water decomposition activity without any scavenger.CDs can accelerate the interface electron extraction about 0.09 ms,while the maximum electron storage time by CDs is up to 0.7 ms.The optimal CDs/NiCo_(2)O_(4)composite(5 wt.%CDs)displays the hydrogen production of 62µmol·h^(−1)·g^(−1) and oxygen production of 29µmol·h^(−1)·g^(−1) at normal atmosphere,which is about 4 times greater than that of pristine NiCo_(2)O_(4).This work provides sufficient evidence on the charge storage of CDs and the interfacial charge kinetics of photocatalysts on the basis of in-situ TPV tests.

Highly efficient metal-free catalyst from cellulose for hydrogen peroxide photoproduction instructed by machine learning and transient photovoltage technology

Great attention has been paid to green procedures and technologies for the design of environmental catalytic systems.Biomassderived catalysts represent one of the greener alternatives for green catalysis.Photocatalytic production of hydrogen peroxide(H_(2)O_(2))from O_(2) and H_(2)O is an ideal green way and has attracted widespread attention.Here,we show a metal-free photocatalyst from cellulose,which has a high photocatalytic activity for the photoproduction of H_(2)O_(2) with the reaction rate up to 2,093μmol/(h·g)and the apparent quantum efficiency of 2.33%.Importantly,a machine learning model was constructed to guide the synthesis of this metal-free photocatalyst.With the help of transient photovoltage(TPV)tests,we optimized their fabrication and catalytic activity,and clearly showed that the formation of carbon dots(CDs)facilitates the generation,separation,and transfer of photo-induced charges on the catalyst surface.This work provides a green way for the highly efficient metal-free photocatalyst design and study from biomass materials with the machine learning and TPV technology.

Preparation of dye-sensitized solar cells with high photocurrent and photovoltage by using mesoporous titanium dioxide particles as photoanode material

Several mesoporous TiO2 （MT） materials were synthesized under different conditions following a hydrothermal procedure using poly（ethylene-glycol）- block-poly（propylene-glycol）-block-poly（ethylene-glycol） （P123） as the template and titanium isopropoxide as the titanium source. The molar ratios of Ti/P123, and the pH values of the reaction solution in an autoclave were investigated. Various techniques such as Brunauer-Emmett-Teller （BET）, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, laser Raman spectrometry （LRS）, scanning electron microscopy （SEM）, and high-resolution transmission electron microscopy （HRTEM） were used to characterize the products. Then, these materials were assembled into dye-sensitized solar cells （DSSCs）. Analysis of the J-V curves and electrochemical impedance spectroscopy （EIS） were applied to characterize the cells. The results indicated that the specific surface area and crystalline structure of these materials provide the possibility of high photocurrent for the cells, and that the structural characteristics of the specimens led to increased electron transfer resistance of the cells, which was beneficial for the improvement of the photovoltage of the DSSCs. The highest photoelectric conversion efficiency of the cells involving MT materials reached 8.33%, which, compared with that of P25- based solar cell （5.88%）, increased by 41.7%.

Surface photovoltage phase spectroscopy study of the photo-induced charge carrier properties of TiO_(2) nanotube arrays

By using the surface photovoltage (SPV) technique based on a lock-in amplifier, surface states located 3.1 eV below the conduction band of TiO_(2) have been detected in TiO_(2) nanotube arrays prepared by anodization of titanium foil in fluoride-based ethylene glycol solution. The photo-induced charge transportation behavior of TiO_(2) nanotube arrays was also studied by quali- tatively analyzing their SPV phase spectra measured under different external bias. When a negative bias was applied, carriers excited from surface states have the same transportation properties as those excited from the valence band; in contrast, when a positive bias was applied, these two kinds of photo-excited carriers exhibit different transportation behavior..

Photoluminescence and surface photovoltage properties of Zn Se nanoribbons

ZnSe nanoribbons were synthesized with chemical vapor deposition route. The excitation power-dependent photol and surface photovoltage （SPV） techniques were used to study the optoelectronic properties of the as-grown ZnSe nanoribbons. Three deep defect （DD）-related emission bands, respectively, centered at 623 nm （DD1）, 563 nm （DD2） and 525 nm （DD3）, emerge orderly with increasing the excitation power, which is attributed to the saturation of the DD states from deeper to shallower level. The SPV spectrum and the corresponding phase spectrum show that DD1 mainly acts as recombination center, while DD2 and DD3 can act as both the recombination center and electron traps. The influence of the trapping electrons on the SPV response dynamic was studied with transient SPV.

High-sensitivity photovoltage based on the interfacial photoelectric effect in the SrTiO_(3-δ)/Si heterojunction

A high sensitivity photovoltaic effect has been observed in a heterojunction composed of n-type wide bandgap oxide SrTiO 3-δ and p-type Si fabricated by laser molecular beam epitaxy.The responsivity of open-circuit photovoltage can reach 10 4 V/W without any amplification under zero bias for the wavelength range from visible to near infrared light in nW-μW order.We attribute the high performance of the photovoltage responsivity to the interfacial photoelectric effects in the SrTiO 3-δ /Si heterojunction.From the experimental results,some ideas can be generalized to improve photovoltaic efficiency and develop high sensitivity photodetectors with wide bandgap oxide materials and Si.

Double-peaked decay of transient photovoltage in nanoporous ZnO/n-Si photodetector

In the present work,a nanoporous ZnO/n-Si structure has been proposed as a new type infrared photodetector.Triggered by one laser pulse with wavelength of 1064 nm,this structure exhibits a double-peak decay of transient photovoltage.Also,the time interval between these two peaks increases linearly with the increase of irradiated pulsed energy,indicating the promising application of this hetero-junction in photo-energy detection of infrared pulsed laser.A possible mechanism for this particular photoresponse has been discussed.

The Bromination Binding of Photosensitive Dyes on Monocrystalline Silicon Surface and Their Surface Photovoltage Spectroscopy

At present, the development and utilization of new photoelectric materials are avery active research field in which the research of semiconductor materials is important.

Transient photovoltage and photoluminescence study of exciton dissociation at indium tin oxide/pentacene interface

The exciton dissociation at ITO/pentacene interface is studied by means of transient photovoltage measurement.Opposite to ITO/NPB,ITO/CuPc or ITO/C60 interface where polarity change of transient photovoltage is observed,no interfacial dissociation is found at room temperature,which indicates a lack of Frenkel excitons in pentacene.Temperature-dependent photoluminescence (PL) is investigated.More like the behavior of inorganic semiconductors,the integrated PL intensity exhibits monotonic decrease with increasing temperature.A nonradiative path with characteristic activation energy of 8 meV is found to dominate at room temperature.The PL measurement also indicates that like in inorganic semiconductors,other types of excitation,for example,free carriers,could be responsible for the photoelectric processes.

Photovoltage of Bacteriorhodopsin in the Purple Membrane Langmuir-Blodgett Film

With the rise of studying biomolecular electronics and biocomputer since the 1980s, bactefiorhodopsin (BR) of purple membrane (PM) from Halobacteria halobium has become an outstanding candidate for studying biomolecular devices due to its stable structure, light-driven proton pumping capability, bistable property, photoelectric responses from ps to ms, as well as its potential application to developing biomolecular devices, biochips and so on. However, the BR not only must, but also can be oriented due

Distance dependence of atomic-resolution near-field imaging on α-Al2O3 （0001） surface with respect to surface photovoltage of silicon probe tip

Recently, we achieved atomic-resolution optical imaging with near-field scanning optical microscopy using photon-induced force detection. In this technique, the surface photovoltage of the silicon-tip apex induced by the optical near field on the surface is measured as the electrostatic force. We demonstrated atomicresolution imaging of the near field on the α-Al2O3 （0001） surface of a prism. We investigated the spatial distribution of the near field by scanning at different tip-sample distances and found that the atomic corrugation of the near-field signal was observed at greater distances than that of the atomic force microscopy signal. As the tip-sample distance increased, the normalized signal-to-noise ratio of the near field is in a gradual decline almost twice that of the frequency shift （Δf）.