Low-temperature Preparation Research Articles

Low-temperature preparation of novel fluoro-fluoro semi-interpenetrating polymer networks as a strong, tough and safe polymer binder for PBX

This work provides an energy saving strategy for strengthening and toughening fluoroelastomer (linear F2314) by using liquid fluorine rubber (HTLF-700). A series of semi-interpenetrating polymer networks based on the F2314 and the crosslinked HTLF-700 (namely F23-CLF-X semi-IPNs) were firstly prepared at low temperatures and characterized using FTIR, SEM, EDS, TGA, DSC, DMA and tensile testing et al. The as-prepared F23-CLF-30 semi-IPNs film possessed well interpenetrating co-continuous phases and thus exhibited prominent mechanical performance with the higher tensile strength (33.0 MPa), the larger elongation at break (165.0%), the better mechanical stability at high and low temperature shock and the higher high-temperature creep resistance compared with the F2314. Meanwhile, the arc Brazilian test indicates that F23-CLF semi-IPNs could be a promising candidate as a polymer binder for polymer bonded explosive (PBX).

Low temperature preparation of high-flux α-alumina tight ultrafiltration membrane by modified co-sintering process

A high-efficiency α-alumina ultrafiltration membrane was proposed and fabricated by co-sintering a gel layer with a pre-sintered interlayer. A pre-sintered interlayer with rigidity and low roughness was used, which was conducive to the preparation of a defect-free and ultra-thin separation layer. In the process of co-sintering, the crystal phase of the separation layer was completely transformed to α-alumina at 950 °C, and permeation of pre-sintered interlayer increase with calcination temperature. The prepared α-alumina ultrafiltration membrane had an ultrathin thickness of only ∼140 nm, pure water permeability as high as 230 L m−2h−1 bar−1, and average pore size approximately ∼7 nm. In the separation of polyvinyl alcohol (PVA) wastewater, the membrane had a rejection rate of 99 % and permeability of 60 L m−2h−1 bar−1. In the removal of Congo red dye, it showed a high rejection rate of >99 % and permeability of 212 L m−2h−1 bar−1.

O3-assisted low-temperature preparation of marginal S and graphitic N co-doped graphene oxide as high-performance electrocatalyst for bisphenol A degradation

In this research, a novel insight was provided for oriented low-temperature S and N doping into graphene oxide (GO).Given the gradual concern in the high-temperature dependence of traditional annealing method for the oriented design of heteroatom doping, utilizing O3 etching-assisted heteroatom doping can simultaneously resolve the problems of energy consumption and doping species design. In this research, with O3 etching, 100 at.% marginal S (C-SOX-C) and 92 at.% graphitic N co-doped O3-S/NGO were successfully synthesized at annealing temperature of 200 °C. Characterization results showed that S and N doping via O3 etching maintained the sheet-like structure of GO without much stacking (layer thickness of 4–5 nm). In addition, active defects were formed by O3 etching and S/N atom doping to provide active center for catalytic reaction. The electrocatalytic degradation behavior proved that 100 % bisphenol A degradation efficiency could be achieved by O3-S/NGO within 30 min and that the main active species generated during the reaction were O2•−, 1O2 and active chlorine. The possible pathways of bisphenol A degradation were also determined to complete the discussion. This project was based on the environmental demand of organic pollution control and suggested an optimal preparation strategy for high-performance catalyst preparation and utilization.

Low-temperature sintered PMnS–PZT multilayer-ceramic for nano-step piezomotor application

Multilayer piezoceramic featured with low driving voltage and large generation force is a basic core component of piezoelectric motors. It has been found that Pb(Mn1/3Sb2/3)O3–Pb(Zr,Ti)O3 (PMnS–PZT) piezoceramic is a powerful system as it simultaneously exhibits a large piezoelectric coefficient (d) and a high mechanical quality factor (Q). However, a quite high sintering temperature (> 1200 ℃) is required, which limits the low-temperature co-firing preparation of the PMnS–PZT multilayer ceramic. In this work, we report a high-performance PMnS–PZT multilayer ceramic using Li2CO3 as a sintering aid and a linear piezoelectric motor based on the multilayer ceramic. The investigations show that a 0.4 wt% Li2CO3-modified PMnS–PZT ceramic sintered at 980 ℃ exhibits excellent ferroelectric, piezoelectric and electromechanical coupling properties. Furthermore, a 12-layer structured linear piezomotor was fabricated based on the Li2CO3-modified PMnS–PZT multilayer ceramic (with Ag/Pd internal electrodes), which shows a superhigh unit volume driving force in comparison with the previously reported piezoelectric motors and a 50 nm step resolution. The obtained results indicated that Li2CO3-modified PMnS–PZT ceramic and its multilayer structure have great potential for high-power device applications.

Low-temperature preparation and electrical properties of CaBi2Nb2O9 piezoelectric ceramic by addition of B2O3

CaBi2Nb2O9 ceramics were fabricated via the solid-state reaction method by the addition of B2O3 as a sintering aid at lower sintering temperatures than that prepared without B2O3. Ferroelectricity, piezoelectricity, and resistivity can be still greatly enhanced when the sintering temperature is decreased from 1075 °C for CaBi2Nb2O9 to 975 °C for CaBi2Nb2O9–0.25 wt. % B2O3. The high resistivity and weak c-axis texture ensure that the ceramics can be fully polarized in a high enough electric field. The increased spontaneous ferroelectric and remanent polarization result in a significant enhancement in the piezoelectric properties of CaBi2Nb2O9–0.25 wt. % B2O3. The sample sintered at 975 °C possesses a high piezoelectric coefficient d33 of ∼15.0 pC/N and resistivity of 1.4 × 106 Ω cm (at 600 °C) along with a high ferroelectric Curie temperature TC of ∼954 °C. This work is beneficial for the preparation of high-temperature piezoelectric ceramics with excellent electrical properties at a low sintering temperature.

Impacts of 0D Cs4PbI6 phase in all-inorganic CsPbI3 perovskites on their physical, optical properties and photovoltaic performances

All-inorganic CsPbI3-based perovskite solar cells were therefore developed under a low preparation temperature of 150 °C through the control of Cs4PbI6/CsPbI3 (or 0-dimentional (0D)/3-dimentional (3D)) phase ratio (or its stoichiometry) by varying the annealing time from 0 to 30 min. In this work, it is disclosed that the stoichiometry among Cs, Pb, and I in the resulting CsPbI3 perovskite absorbers can be manipulated through the annealing time, where the 0D Cs4PbI6 phase in the films is reduced with the increase in the annealing time. The Cs4PbI6 phase in the CsPbI3 perovskites results in (i) the effective passivation of the shallow defects, thus increasing the carrier lifetime, and (ii) the suppression of the δ-CsPbI3 yellow phase, improving the phase stability. Moreover, the appropriate annealing time of 20 min gives rise to the suitable Cs4PbI6/CsPbI3 (0D/3D) phase ratio in the perovskite absorber, thereby leading to the enhanced efficiency of about 7.6%.

Effect of temperature and D-sorbitol reducing agent content on the structural and optical properties of copper oxide thin films deposited by ultrasonic spray pyrolysis

In this article are investigated the optical and structural properties of copper oxide thin films deposited by ultrasonic spray pyrolysis and the effect of the substrate temperature and the D-sorbitol precursor solution reducing agent. The Cu2O/CuO phase transition, a key factor for the development of this metal oxide for photovoltaics and other applications, is studied using X-ray diffraction, confocal micro-Raman and transmittance spectroscopy. The obtained structural and optical properties are correlated to analyze the phase transition and the effect of the reducing agent concentration combined to the controlled and precisely defined preparation temperature. The study permitted to use a relatively low preparation temperature of 230 ∘C to produce a single Cu2O phase using the D-sorbitol reducing agent. The optimized structural and optical properties were obtained without the need of using D-sorbitol in excess compared to copper acetate, as usually done when using glucose, thereby reducing the density of defects and improving electrical properties for optoelectronic applications.

Low-temperature fabrication of NASICON-type LATP with superior ionic conductivity

NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) has attracted much attention as a fast lithium-ion conductor for all-solid-state lithium-based batteries. However, the large grain-boundary resistance and high sintering temperature above 950 °C for pure LATP electrolytes hinder their practical application in lithium-based batteries. Here, a low-temperature preparation approach for the superionic conductor LATP electrolyte with sintering aids is proposed. By introducing sintering aids Li3PO4, LiBO2·0.3H2O, and binary 0.32Li3PO4-0.68LiBO2·0.3H2O, LATP-based pellets can be fabricated at optimized sintering temperatures below 900 °C. The resultant LATP-based pellets maintain a high relative density and homogeneous microstructure, which arises from the sintering aid to facilitate the grain rearrangement and fill the interstices between grains. The LATP pellets using sintering aid Li3PO4 achieve a high ionic conductivity of 5.2 × 10−4 S cm−1 at a low temperature of 800 °C, 7.3 times that (7.1 × 10−5 S cm−1) of pure LATP pellets sintered at 950 °C, which demonstrates the effectiveness of low-temperature preparation approach to reducing the preparation cost and optimizing the ionic conductivity of LATP-based electrolytes.

Low temperature preparation of W-doped In2O3 transparent electrodes for p-i-n structured perovskite solar cells

W-doped In2O3 (IWO) films prepared by reactive plasma deposition (RPD) technique at 150 °C have been studied to replace Sn-doped In2O3 (ITO) serving as transparent electrodes for p-i-n structured perovskite solar cells. The optical and electrical properties of IWO films were found to depend on the oxygen partial pressure of deposition process. Compared with the reference ITO films, the IWO films obtained at an oxygen partial pressure of 0.12 Pa exhibited prominent performance, including higher near-infrared transmittance and carrier mobility. Furthermore, the IWO films showed higher work function than that of the ITO films, resulting in the enhancement of open-circuit voltage (0.982 V vs 0.901 V) and conversion efficiency (12.9 % vs 11.9 %). It can be attributed to that high work function of the IWO films reduced the carrier transport barrier at the interface between transparent electrode and PEDOT:PSS and enhanced the carrier collection near the edge of the perovskite bandgap. The excellent properties of the RPD-prepared IWO films indicate that it is a promising transparent electrode material for p-i-n structured perovskite solar cells, especially for applications requiring low-temperature fabrication.

Photocurrent and Gelation Properties of Polyphenol-Modified Titanium-Oxo Compounds.

Organic-inorganic hybrid metal-polyphenols as stable structural modules have gained extensive interest due to their diverse applications. However, titanium-oxo compounds (TOCs) with large molecular polyphenols have been less explored, and they were expected to be different from small polyphenols with isolated metal ions. Herein, 4-methyl-esculetin (Mesc), a catechol derivative, was selected to construct three TOCs, namely, [Ti17O24(Mesc)4(OiPr)16] (1), [Ti12O14(OiPr)18][Ti16O14(Mesc)12(OiPr)14] (2), and [Ti3O(Mesc)2(OAc)2(OiPr)4] (3). These compounds were structurally characterized. Photocurrent responses were evaluated using the compound-sensitized TiO2 electrodes. It was found that the current densities of 1-3 electrodes are in the order of 1 ≫ 3 > 2, which relates to the ligand-to-TiO core and ligand-to-ligand charge transfers (LMCT and LLCT, respectively). Density functional theory calculations showed that the lowest band gap of 1 originates from its LLCT. Compound 1 reacted with polyphenol tannin (TA) to form a fully transparent and robust gel (1-TA), and the gelation properties were investigated. Using the gel as a nano-TiO2 fixing agent, solar cell electrodes were prepared by a low-temperature wet method. The photocurrent responsive behavior of the 1-TA/TiO2 electrode was compared with that of the 1-sensitized traditional high-temperature-treated TiO2 electrode. Although the current density of the former is somewhat lower than that of the traditional electrode, the low-temperature wet preparation of the 1-TA/TiO2 electrode is more energy-efficient and sustainable.

Alkali Metal Cations Modulate the Energy Level of SnO2 via Micro-agglomerating and Anchoring for Perovskite Solar Cells.

N-type tin oxide (SnO2) films are commonly used as an electron transport layer (ETL) in perovskite solar cells (PSCs). However, SnO2 films are of poor quality due to facile agglomeration under a low-temperature preparation method. In addition, energy level mismatch between the SnO2 and perovskite (PVK) layer as well as interfacial charge recombination would cause open-circuit voltage loss. In this work, alkali metal oxalates (M-Oxalate, M = Li, Na, and K) are doped into the SnO2 precursor to solve these problems. First, it is found that the hydrolyzed alkali metal cations tend to change colloid size distribution of SnO2, in which Na-Oxalate with suitable basicity leads to most uniform colloid size distribution and high-quality SnO2-Na films. Second, the electron conductivity is enhanced by slightly agglomerated SnO2-Na, which facilitates the transmission of electrons. Third, alkali metal cations increase the conduction band level of SnO2 in the sequence of K+, Na+, and Li+ to promote band alignment between ETLs and perovskite. Based on the optimized film quality and energy states of SnO2-Na, the best PSC efficiency of 20.78% is achieved with a significantly enhanced open-circuit voltage of 1.10 V. This work highlights the function of alkali metal salts on the colloid particle distribution and energy level modulation of SnO2.

Novel SiBCN composite fibers with broadband and strong electromagnetic wave absorption performance

The SiBCN composite fibers with strong electromagnetic wave (EMW) absorption performance were successfully prepared via polymer-derived ceramics (PDCs) and electrospinning methods at relatively lower preparation temperature. The results showed that the in-situ generated free carbon which existed in the matrix in the form of simple substance and was characterized by low crystallinity. The graphite carbon improved the dielectric loss and properties of SiBCN composite fibers. In particular for the SiBCN composite fibers pyrolyzed at 1300 °C, the in-situ generated nano β-SiC crystallization increased the EMW absorption performance significantly. The minimum reflection loss (RL min ) of the SiBCN-3 reached − 54.91 dB at 2.35 mm and the effective absorption band (EAB, RL ≤ −10 dB) reached 4.72 GHz (13.28–18 GHz, 1.75 mm). Hence, the SiBCN fibers prepared at relatively lower temperature give good absorption performance and predict a broader application prospect in the field of EMW absorption materials. • SiBCN fibers with excellent EMW absorption performance were successfully prepared. • The in-situ generated free carbon improved the dielectric loss and properties of SiBCN fibers. • The minimum reflection loss (RL min ) of SiBCN-3 reached − 54.91 dB at 2.35 mm. • The effective absorption band (EAB, RL ≤ −10 dB) of SiBCN-3 reached 4.72 GHz (13.28–18 GHz) at 1.75 mm.

Growth-Promoting Mechanism of Bismuth-Doped Cu(In,Ga)Se2 Solar Cells Fabricated at 400 °C.

The classical high-temperature synthesis process of Cu(In,Ga)Se2 (CIGS) solar cells limits their applications on high-temperature intolerant substrates. In this study, a novel low-temperature (400 °C) fabrication strategy of CIGS solar cells is reported using the bismuth (Bi)-doping method, and its growth-promoting mechanism is systematically studied. Different concentrations of Bi are incorporated into pure chalcopyrite quaternary target sputtered-CIGS films by controlling the thickness of the Bi layer. Bi induces considerable grain growth improvement, and an average of approximately 3% absolute efficiency enhancement is achieved for Bi-doped solar cells in comparison with the Bi-free samples. Solar cells doped with a 50 nm Bi layer yield the highest efficiency of 13.04% (without any antireflective coating) using the low-temperature technology. The copper-bismuth-selenium compounds (Cu-Bi-Se, mainly Cu1.6Bi4.8Se8) are crucial in improving the crystallinity of absorbers during the annealing process. These Bi-containing compounds are conclusively observed at the grain boundaries and top and bottom interfaces of CIGS films. The growth promotion is found to be associated with the superior diffusion capacity of Cu-Bi-Se compounds in CIGS films, and these liquid compounds function as carriers to facilitate crystallization. Bi atoms do not enter the CIGS lattices, and the band gaps (Eg) of absorbers remain unchanged. Bi doping reduces the number of CIGS grain boundaries and increases the copper vacancy content in CIGS films, thereby boosting the carrier concentrations. Cu-Bi-Se compounds in grain boundaries significantly enhance the conductivity of grain boundaries and serve as channels for carrier transport. The valence band, Fermi energy level (EF), and conduction band of Bi-doped CIGS films all move downward. This band shift strengthens the band bending of the CdS/CIGS heterojunction and eventually improves the open circuit voltage (Voc) of solar cells. An effective doping method and a novel mechanism can facilitate the low-temperature preparation of CIGS solar cells.

Improvement of nanopore structure SnO2 electron-transport layer for carbon-based CsPbIBr2 perovskite solar cells

SnO2 has been widely used in perovskite solar cells (PSCs) and LEDs as a flat electron transport layer (ETL), because of its low preparation temperature and low energy consumption. However, electrons are easily captured by defects on the ETL, resulting in ion migration of perovskite, which increases the extensive hysteresis index (HI) of PSCs. By preparing surface microstructures (such as mesoporous structure and nanowire array) on the ETL, the electron transmission capacity can be improved effectively, which reduces the HI and increases photoelectric conversion efficiency (PCE).In this paper, we use a simple and high fault-tolerant method to prepare the SnO2 ETL with nanopore structure (NP–SnO2) at low temperature. The polystyrene microsphere sphere templates were prepared on flat SnO2 film by a vertical deposition method, and then SnO2 films with NP-SnO2 were prepared by template method. The size and density of nanopores in the NP-SnO2 are controlled by controlling the size of PS spheres and the concentration of PS colloidal solution. The nanopores structure could improve the quality of CsPbIBr2 crystal films. Moreover, the nanopore structure can increase the contact area between the SnO2 ETL and the CsPbIBr2 film, which provides more channels for electron transmission.The results show that CsPbIBr2 PSCs based on NP-SnO2 ETL can obtain the champion PCE, which is 6.68% (25.33% higher than the PSCs based on flat SnO2 ETL), and the HI of the PSCs based on NP-SnO2 ETL was reduced from 0.36 to 0.17.

Low-temperature preparation of superhydrophilic coatings using tetraethoxysilane and colloidal silica by sol-gel method

In this study, a simple and facile method for producing superhydrophilic coatings by thermal curing at a low temperature of 100 °C or less for 2 h without a calcination process at high temperatures was reported. Hydrophilic coating solutions were prepared using tetraethoxysilane (TEOS) and colloidal silica as precursors by sol-gel method. After applying the prepared coating solution to a glass slide by dip-coating, a superhydrophilic coating was prepared by thermal curing at 100 °C for 2 h. In this process, the effect of the amount and concentration of colloidal silica added to the polysiloxane sol derived from TEOS on the superhydrophilicity of the coatings was observed. The coatings were characterized by water contact angle (WCA) analyzer, FT-IR spectroscopy, field emission scanning electron microscopy (FE-SEM), and atomic force microscope (AFM). In the coatings prepared using 10 wt% colloidal silica, as the content of colloidal silica added increased to 8 g, 16 g, 24 g, and 40 g, the WCA of the coating decreased to 56°, 37°, 10°, and 5°, respectively. From this result, it can be seen that a superhydrophilic coating, which shows a WCA of 5° or less, can be obtained when 40 g of colloidal silica is added. The FT-IR results suggest that the superhydrophilic coating consists of more hydrophilic components than the coating using only the polysiloxane sol without the addition of colloidal silica. In addition, the superhydrophilic coating showed a rough surface morphology in SEM and AFM observations. It was considered that the superhydrophilicity of the coating was derived from the increase of hydrophilic chemical components and surface roughness by adding colloidal silica. Moreover, the superhydrophilic coating showed an excellent anti-fogging property and a self-cleaning ability.

Low temperature-processed stable and high-efficiency carbon-based CsPbI2Br perovskite solar cells by additive strategy

All-inorganic perovskite solar cells require high-temperature preparation processes, which severely hinders their further commercial development. Inorganic perovskite materials have a high crystallization barrier, so the crystallinity is poor under low temperature conditions, resulting in poor device performance. Therefore, it is an important challenge to develop an excellent low-temperature preparation process. In this paper, the crystallization kinetics of the CsPbI2Br perovskite film under low temperature conditions was studied, and it was found that the perovskite was not completely crystallized during low temperature crystallization, and PbI2 remained. The PbI2 residue not only caused the appearance of lead defects but also formed insoluble CsBr due to the insufficient reaction of the raw materials. Through the interaction between the organic molecules 3-Amino-3-(3-pyridyl)propionic Acid (PA) and PbI2, the crystallization reaction process can be effectively improved. Eliminating the residual PbI2 also effectively inhibited the precipitation of CsBr, thereby significantly improved the crystallinity of CsPbI2Br. Efficiencies of 10.95% are achieved for low-temperature-processed CsPbI2Br planar-architecture FTO/SnO2/CsPbI2Br/carbon, and the obtained device also showed good stability in the air.

Design and reactive magnetron sputtering of thermochromic coatings

Thermochromic coatings based on vanadium dioxide exhibit great potential in various fields, including smart energy-saving windows with temperature-dependent transmittance in the infrared at preserved transmittance in the visible. However, these promises come with challenges concerning the low-temperature preparation of high-quality crystalline VO2-based films by industry-friendly techniques and the simultaneous optimization of all coating characteristics, such as thermochromic transition temperature, luminous transmittance, and modulation of solar energy transmittance. This Perspective outlines these challenges, highlights the recent progress in the field of design and reactive magnetron sputtering of thermochromic coatings, explains the physics that allowed this progress, and provides ideas and recommendations for future research. A combination of the advantages of controlled high-power impulse magnetron sputtering with the not yet fully experimentally utilized multilayered designs constitutes the main reason why further progress is anticipated in the future.

Preparation of CuI films by continuous ion layer adsorption reaction (SILAR)

Transparent conductive CuI films were prepared on ITO glass substrates using a low-temperature liquid-phase film preparation process, the continuous ion layer adsorption reaction (SILAR) method. The influence of process parameters on the film quality and film surface morphology was investigated, and the relationship between the growth rate of the films and the concentration of the reaction solution as well as the number of cycles was studied and analyzed. The experimental conditions for the preparation of CuI films with the highest transmittance were as follows: the concentration of the anion driving solution was 0.075 mol/L. The film thickness of the CuI films increased with the number of cycles, and films with a thickness of 1.73μm could be produced in 40 cycles. The films were tested by XRD and SEM and showed high purity, flat and dense surface.

Hydrogen Tetrachloroaurate-Modulated PEDOT:PSS film assembled with conductive NPB buffer layer for High-Performance planar perovskite solar cells

• Inorganic HAuCl 4 doping combined organic NPB post-treatment strategy was proposed. • High PCE of 19.20% for Au@PEDOT:PSS/NPB PSCs is achieved on rigid substrate. • Flexible Au@PEDOT:PSS/NPB PSCs achieve 14.04% PCE with strong wrinkle resistance. • Improved hysteresis and stability of PSCs are realized via synchronous regulation. The further improvements in optoelectronic properties, hydrophobicity of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transport layers, as well as regulation of defect states within devices are essential to promote the continued development of inverted p-i-n rigid and flexible planar perovskite solar cells (PSCs). However, the strong hygroscopicity, poor surface morphology, lower work function and coil configuration of pristine PEDOT:PSS films are detrimental to their own performance and growth dynamics process of perovskites, often resulting in sever energy losses and poor device performance. Herein, hydrogen tetrachloroaurate (III) hydrate (HAuCl 4 ·3H 2 O) additive is combined with a conductive N,N'-Bis-(1-naphthalenyl)-N,N'-bis-phenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) buffer layer to boost device performance by systematically modulating PEDOT:PSS and perovskite film. Wherein, the redox reaction between PEDOT:PSS and HAuCl 4 can cause phase segregation of PEDOT:PSS, improving the hydrophobicity, electrical conductivity, work function and surface morphology of the films. The reduced gold nanoparticles will produce localized surface plasmon resonance effects, thus enhancing the utilization of solar radiation by perovskite films. Furthermore, the suitable energy level alignment of NPB layer relative to perovskite and Au@PEDOT:PSS films will sufficiently exploit the dissociative excitons to facilitate effective hole transport, and the N atoms in NPB can also passivate defects at the interface by binding to uncoordinated Pb 2+ ions, thereby reducing non-radiative open-circuit voltage loss and increasing short-circuit current density. A high power conversion efficiency (PCE) of 19.20% can be achieved for MA 0.85 FA 0.15 PbI 3 based p-i-n PSCs with negligible hysteresis and enhanced stability of devices. Similarly, the corresponding flexible device achieves a PCE of 14.04% with improved crumpling durability throughout low temperature preparation conditions below 140 °C. Our work presents a facile method to prepare high-efficient inverted PSCs while achieving improved long-term device stability.

Improving the electrical performance of inverted perovskite solar cell with LiF anode buffer layer

Although the electrical performance of inverted PSCs is a bit lower than that of conventional PSCs at present, it has attracted increasing research attention thanks to its simple architecture for low preparation temperature and negligible hysteresis, and subsequently a high opportunity for industrial application. In general, PEDOT:PSS is employed to serve as hole transport layer (HTL) in inverted PSCs due to its high conductivity, high light transmittance, and aqueous dispersion. However, the mismatch of energy level between PEDOT:PSS and ITO is detrimental to extract the photo-induced holes, hampering further enhancement of the electrical performance of inverted PSCs. Here, a LiF anode buffer layer, whose optimization thickness is 7 nm, has been employed to modify the PEDOT:PSS HTL in inverted PSCs. Thanks to the LiF anode buffer layer, a dramatically enhancement of PCE from 16.01% of reference sample with pristine PEDOT:PSS to 18.18% of PSCs with LiF/PEDOT: PSS HTL. This enhancement is mainly ascribed to improve the charge extraction ability due to the diople effect of LiF. Therefore, this work provides a simple and effective method to increase the electrical performance of inverted PSCs. • A LiF anode buffer layer is employed to modify the PEDOT: PSS in inverted PSCs. • The PCE is a dramatically enhancement from 16.01% with pristine PEDOT:PSS to 18.18% with LiF/PEDOT:PSS. • This work provides a simple and effective method to increase the electrical performance of inverted PSCs.