Surface repair of wide-bandgap perovskites for high-performance all-perovskite tandem solar cells

Wide-bandgap(WBG)perovskite solar cells(PSCs)play a fundamental role in perovskite-based tandem solar cells.However,the efficiency of WBG PSCs is limited by significant open-circuit voltage losses,which are primarily caused by surface defects.In this study,we present a novel method for modifying surfaces using the multifunctional S-ethylisothiourea hydrobromide(SEBr),which can passivate both Pb^(-1)and FA^(-1)terminated surfaces,Moreover,the SEBr upshifted the Fermi level at the perovskite interface,thereby promoting carrier collection.This proposed method was effective for both 1.67 and 1.77 eV WBG PSCs,achieving power conversion efficiencies(PCEs)of 22.47%and 19.90%,respectively,with V_(OC)values of 1.28 and 1.33 V,along with improved film and device stability.With this advancement,we were able to fabricate monolithic all-perovskite tandem solar cells with a champion PCE of 27.10%,This research offers valuable insights for passivating the surface trap states of WBG perovskite through rational multifunctional molecular engineering.

Low-cost biodegradable lead sequestration film for perovskite solar cells

Despite the high efficiency that has been achieved for the perovskite solar cells(PSCs),the hazardous lead leakage from the perovskite absorber layer is one of the crucial barriers still hindering its penetration into the commercial market for a large-scale installation.Herein,we report a novel low-cost and biodegradable lead sequestration layer with high compatibility for up-scalable encapsulation of PSCs.Through a precisely designed cross-linking reaction of chemical agents,the as-made biodegradable chitosan composite film shows enhanced mechanical strength,chemical stability,and lead adsorption capacity.The designed encapsulation strategy reduces over 99.99% lead leakage to <2 ppb under varied simulations of weather conditions(hail,rain,or flood),which meet the safe level of drinking water set by the US Environmental Protection Agency(EPA).Moreover,the PSC efficiency is improved from 21.91% to22.82% due to the improved light absorption from the printed biodegradable lead absorption film.Finally,we present a prototype process of accumulation and recycling of lead compounds in PSCs derbies via the biodegradation process.Based on the low-cost biodegradable lead sequestration film,this environmental-friendly encapsulation strategy could address the lead leakage issue for further commercialization of PSCs.

Interfacial and Vacancies Engineering of Copper Nickel Sulfide for Enhanced Oxygen Reduction and Alcohols Oxidation Activity

Rational design and construction of highly efficient nonprecious electrocatalysts for oxygen reduction and alcohols oxidation reactions(ORR,AOR)are extremely vital for the development of direct oxidation alkaline fuel cells,metal-air batteries,and water electrolysis system involving hydrogen and value-added organic products generation,but they remain a great challenge.Herein,a bifunctional electrocatalyst is prepared by anchoring CuS/NiS_(2)nanoparticles with abundant heterointerfaces and sulfur vacancies on graphene(Cu_(1)Ni_(2)-S/G)for ORR and AOR.Benefiting from the synergistic effects between strong interfacial coupling and regulation of the sulfur vacancies,Cu_(1)Ni_(2)-S/G achieves dramatically enhanced ORR activity with long term stability.Meanwhile,when ethanol is utilized as an oxidant for AOR,an ultralow potential(1.37 V)at a current density of 10 mA cm-2 is achieved,simultaneously delivering a high Faradaic efficiency of 96%for ethyl acetate production.Cu_(1)Ni_(2)-S/G also exhibits catalytic activity for other alcohols electrooxidation process,indicating its multifunctionality.This work not only highlights a viable strategy for tailoring catalytic activity through the synergetic combination of interfacial and vacancies engineering,but also opens up new avenues for the construction of a self-driven biomass electrocatalysis system for the generation of value-added organic products and hydrogen under ambient conditions.

Efficient and stable planar all-inorganic perovskite solar cells based on high-quality CsPbBr3 films with controllable morphology

All-inorganic cesium lead bromide(CsPbBr3)perovskite is attracting growing interest as functional materials in photovoltaics and other optoelectronic devices due to its superb stability.However,the fabrication of high-quality CsPbBr3 films still remains a big challenge by solution-process because of the low solubility of the cesium precursor in common solvents.Herein,we report a facile solution-processed approach to prepare high-quality CsPbBr3 perovskite films via a two-step spin-coating method,in which the Cs Br methanol/H2 O mixed solvent solution is spin-coated onto the lead bromide films,followed by an isopropanol-assisted post-treatment to regulate the crystallization process and to control the film morphology.In this fashion,dense and uniform CsPbBr3 films are obtained consisting of large crystalline domains with sizes up to microns and low defect density.The effectiveness of the resulting CsPbBr3 films is further examined in perovskite solar cells(PSCs)with a simplified planar architecture of fluorine–doped tin oxide/compact Ti O2/CsPbBr3/carbon,which deliver a maximum power conversion efficiency of 8.11%together with excellent thermal and humidity stability.The present work offers a simple and effective strategy in fabrication of high-quality CsPbBr3 films for efficient and stable PSCs as well as other optoelectronic devices.

Groups-dependent phosphines as the organic redox for point defects elimination in hybrid perovskite solar cells

Lead(Pb)^(0) and iodine(I)^(0) point defects generated during perovskite solar cell(PSC)fabrication and photoconversion form deep band energy levels as the carriers’recombination centers.These defects not only deteriorate device efficiency,but also facilitate chemical degradation with ion migration,resulting in restricted device lifetime.Herein,we present a novel type of phosphines as the point defects stabilizer for hybrid perovskite solar cells with enhanced performances.Three phosphines with varied side groups of tributyl,trioctyl and triphenyl are exampled as the dopants in perovskite films.The group dependent redox properties were observed in the perovskite film,dependent on their molecular weights and steric hinderances of phosphines.The partially oxidized tributyl phosphine(TBUP)with additional tributyl phosphine oxides(TBPO)is efficient in reduction of lead(Pb)^(0) and iodine(I)^(0) concentrations during the device fabrication and operation.The device with TBUP-TBPO pair showed enhanced power conversion efficiency(PCE)to 20.48% and maintain 91.7% of their initial PCEs after 500 h at 65℃ thermal annealing.Thus,this work presents an efficient route of utilize the phosphine species to reduce point defects in the perovskite film,which promoting further development of novel phosphorous additives with defects stabilization,interface passivation and encapsulation for low-cost solution processed PSCs.

Interface passivation engineering for hybrid perovskite solar cells

The allure of high efficiency and low-temperature solution-processed organic-inorganic hybrid perovskite solar cells(PSCs)are inspiring scientists to seek for its commercialization.Interface passivation engineering has become an effective way to further enhance the efficiency and stability of PSCs by defect passivation,reduces the charge recombination and ion migration initiation and hysteresis control,etc.Herein,we have summarized the effects and recent research progress of interface passivation engineering in PSCs.Interface passivation layers can be realized by using the solution and/or vacuum evaporation processes which are very adaptable to varied materials with different properties and fabrication processes for enhanced photovoltaic performance and stability.

“Coffee ring” controlment in spray prepared >19% efficiency Cs_(0.19)FA_(0.81)PbI_(2.5)Br_(0.5) perovskite solar cells

Achieving high-quality perovskite films with uniform morphology and homogeneous crystallinity is challenging owing to the coffee ring effect(CRE) in the spray-coating technologies. In this study, an evaporation/spray-coating two-step deposition method is used to fabricate Cs_(0.19)FA_(0.81)PbI_(2.5)Br_(0.5)light harvesters for perovskite solar cells(PSCs). Considering the solid–liquid reaction, we establish a reaction-dependent regulating strategy that inhibits CRE successfully and prepare a high-quality perovskite layer, wherein the solvent for the FAI/Br solution during the spraying process is changed from isopropanol to n-butyl alcohol(NBA). The retarded-drying-enhanced spreading of the NBA solution inhibits contact line pinning to suppress the capillary flows and increases the reaction between metal halides(CsI/PbI_(2)) and organic salts(FAI/Br), which result in a reduction in the accumulation of solutes in the periphery effectively inhibiting CRE. Consequently, we obtain a high performance Cs_(0.19)FA_(0.81)PbI_(2.5)Br_(0.5) PSC with a power conversion efficiency(PCE) of 19.17%. An enlarged perovskite film(10 × 10 cm^(2)) containing 40 sub-cells is prepared. The average PCE of these devices is 18.33 ± 0.56%, proving the reliability of the "coffee ring" regulating strategy. This study provides an effective approach for CRE controlment in spraying technology to achieve high repeatability devices with good performance.

Efficient flexible perovskite solar cells and modules using a stable SnO_(2)-nanocrystal isopropanol dispersion

The outstanding advantages of lightweight and flexibility enable flexible perovskite solar cells(PSCs)to have great application potential in mobile energy devices.Due to the low cost,low-temperature processibility,and high electron mobility,SnO_(2) nanocrystals have been widely employed as the electron transport layer in flexible PSCs.To prepare high-quality SnO_(2) layers,a monodispersed nanocrystal solution is normally used.However,the SnO_(2) nanocrystals can easily aggregate,especially after long periods of storage.Herein,we develop a green and cost-effective strategy for the synthesis of high-quality SnO_(2) nanocrystals at low temperatures by introducing small molecules of glycerol,obtaining a stable and well-dispersed SnO_(2)-nanocrystal isopropanol dispersion successfully.Due to the enhanced dispersity and super wettability of this alcohol-based SnO_(2)-nanocrystal solution,large-area smooth and dense SnO_(2) films are easily deposited on the plastic conductive substrate.Furthermore,this contributes to effective charge transfer and suppressed non-radiative recombination at the interface between the SnO_(2) and perovskite layers.As a result,a greatly enhanced power conversion efficiency(PCE)of 21.8%from 19.2%is achieved for small-area flexible PSCs.A large-area 5 cm×5 cm flexible perovskite solar mini-module with a champion PCE of 16.5%and good stability is also demonstrated via this glycerol-modified SnO_(2)-nanocrystal isopropanol dispersion approach.

The issues on the commercialization of perovskite solar cells

Perovskite solar cells have aroused a worldwide research upsurge in recent years due to their soaring photovoltaic performance,ease of solution processing,and low cost.The power conversion efficiency record is constantly being broken and has recently reached 26.1%in the lab,which is comparable to the established photovoltaic technologies such as crystalline silicon,copper indium gallium selenide and cadmium telluride(CdTe)solar cells.Currently,perovskite solar cells are standing at the entrance of industrialization,where huge opportunities and risks coexist.However,towards commercialization,challenges of up-scaling,stability and lead toxicity still remain,the proper handling of which could potentially lead to the widespread adoption of perovskite solar cells as a low-cost and efficient source of renewable energy.This review gives a holistic analysis of the path towards commercialization for perovskite solar cells.A comprehensive overview of the current state-of-the-art level for perovskite solar cells and modules will be introduced first,with respect to the module efficiency,stability and current status of industrialization.We will then discuss the challenges that get in the way of commercialization and the corresponding strategies to address them,involving the upscaling,the stability and the lead toxicity issue.Insights into the future direction of commercialization of perovskite photovoltaics was also provided,including the flexible perovskite cells and modules and perovskite indoor photovoltaics.Finally,the future perspectives towards commercialization are put forward.

Erratum to:Efficient flexible perovskite solar cells and modules using a stable SnO_(2)-nanocrystal isopropanol dispersion

Erratum to Nano Research,2024,17(4):2704-2711 https://doi.org/10.1007/s12274-023-6115-y(1)In the article,the table of contents(TOC)image was unfortunately mispresented.

Ultrafast-laser-treated poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)electrodes with enhanced conductivity and transparency for semitransparent perovskite solar cells

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)is an important organic electrode for solution-processed low-cost electronic devices.However,it requires doping and post-solvent treatment to improve its conductivity,and the chemicals used for such treatments may affect the device fabrication process.In this study,we developed a novel route for exploiting ultrafast lasers(femtosecond and picosecond laser)to simultaneously enhance the conductivity and transparency of PEDOT:PSS films and fabricate patterned solution-processed electrodes for electronic devices.The conductivity of the PEDOT:PSS film was improved by three orders of magnitude(from 3.1 to 1024 S·cm^(–1)),and high transparency of up to 88.5%(average visible transmittance,AVT)was achieved.Raman and depthprofiling X-ray photoelectron spectroscopy revealed that the oxidation level of PEDOT was enhanced,thereby increasing the carrier concentration.The surface PSS content also decreased,which is beneficial to the carrier mobility,resulting in significantly enhanced electrical conductivity.Further,we fabricated semitransparent perovskite solar cells using the as-made PEDOT:PSS as the transparent top electrodes,and a power conversion efficiency of 7.39%was achieved with 22.63%AVT.Thus,the proposed route for synthesizing conductive and transparent electrodes is promising for vacuum and doping-free electronics.

In-situ monitored chemical bath deposition of planar NiO x layer for inverted perovskite solar cell with enhanced efficiency

As a convenient,low-cost and up-scalable solution route,chemical bath deposition(CBD)has exhibited impressive advantages in fabricating electron transporting materials like SnO_(2),achieving record efficien-cies for regular n-i-p perovskite solar cells(PSCs).However,for the hysteresis-free and potentially more stable inverted p-i-n PSCs,CBD processing is rarely studied to improve the device performance.In this work,we first present a CBD planar NiO x film as the efficient hole transport layer for the inverted per-ovskite solar cells(IPSCs).The morphologies and semiconducting properties of the NiO x film can be ad-justed by varying the concentration of[Ni(H 2 O)x(NH 3)6-x]2+cation via in-situ monitoring of the CBD re-action process.The characterizations of ultraviolet photoelectron spectroscopy,transient absorption spec-troscopy,time-resolved photoluminescence suggest that the CBD planar NiO x film possesses enhanced conductivity and aligned energy band levels with perovskite,which benefits for the charge transport in the IPSCs.The devices based on planar NiO x at 50°C and low nickel precursor concentration achieved an enhanced efficiency from 16.14%to 18.17%.This work established an efficient CBD route to fabricate planar NiO x film for PSCs and paved the way for high performance PSCs with CBD-prepared hole transporting materials.

Recent progress in perovskite solar cells:from device to commercialization

Perovskite solar cells(PSCs) are undergoing rapid development and the power conversion efficiency reaches 25.7% which attracts increasing attention on their commercialization recently.In this review,we summarized the recent progress of PSCs based on device structures,perovskite-based tandem cells,large-area modules,stability,applications and industrialization.Last,the challenges and perspectives are discussed,aiming at providing a thrust for the commercialization of PSCs in the near future.

氧化锡陶瓷的飞秒激光3D非线性光刻

氧化锡是一种宽带隙半导体材料,广泛用于气体传感、光电和催化等领域.微米级至纳米级的复杂三维几何结构使传统的氧化锡陶瓷具有新的特性和功能.由于具有高的机械韧性和强度,陶瓷不易铸造或加工.增材制造为陶瓷材料灵活的几何造型带来了巨大的机会,但是极高的熔化温度使其在普通的3D打印方法上更加困难,而在微米或纳米尺度任意成形氧化锡陶瓷始终是一个挑战.本文中,我们利用在超快激光辐照下聚合的陶瓷前驱体,形成复杂且任意的3D陶瓷聚合物结构,通过煅烧处理后转变为具有均匀收缩率的高密度纯氧化锡陶瓷,特征尺寸可降至亚微米.透射电子显微镜(TEM)分析显示,氧化锡陶瓷纳米晶体的晶粒尺寸为2.5±0.4 nm.这项工作为制造精度高达亚百纳米的任意3D氧化锡陶瓷纳米结构提供了可能性,从而使其在不同领域更具应用前景.

固-气反应制备高效Rb_(0.04)-Cs_(0.14)FA_(0.86)Pb(Br_(y)I_(1-y))_(3)钙钛矿太阳电池

针对有机-无机杂化钙钛矿材料在气相制备过程中离子迁移速率慢这一关键科学问题,开发了一种多级气氛反应工艺.该工艺利用Cl离子在薄膜中的高迁移能力,首先将钙钛矿前驱体薄膜(RbCs-PbI_(2))在低温下(120℃)与FACl反应,生成一种RbCs-FA_(2)Pb(Br_(y)I_(1-y))4中间相;然后再与FAI气氛在高温下(160℃)反应生成Rb Cs-FAPb(Br_(y)I_(1-y))_(3)钙钛矿.所生成的中间相与FAI反应活性较高,能有效促进固-气界面的离子迁移与交换.基于该中间相策略,最终制备出高质量Rb_(0.04)-Cs_(0.14)FA_(0.86)Pb(Br_(y)I_(1-y))_(3)钙钛矿薄膜,所组装的太阳电池效率达19.59%.同时,大尺寸组件效率达15%,表明该气相反应工艺在大尺寸钙钛矿电池组件制备方面具备应用潜力.

Nitrogen‐doped tin oxide electron transport layer for stable perovskite solar cells with efficiency over 23%

Tin oxide has made a major breakthrough in high-efficiency perovskite solar cells(PSCs)as an efficient electron transport layer by the low-temperature chemical bath deposition method.However,tin oxide often contains pernicious defects,resulting in unsatisfactory performance.Herein,we develop high-quality tin oxide films via a nitrogen-doping strategy for high-efficiency and stable planar PSCs.The aligned energy level at the interface of doped SnO_(2)/perovskite,more excellent charge extraction and reduced nonradiative recombination contribute to the enhanced efficiency and stability.Correspondingly,the power conversion efficiency of the devices based on N‐SnO_(2) film increases to 23.41% from 20.55% of the devices based on the pristine SnO_(2).The N-SnO_(2) devices show an outstanding stability retaining 97.8% of the initial efficiency after steady-state output at a maximum power point for 600s under standard AM1.5G continuous illumination without encapsulation,while less than 50% efficiency remains for the devices based on pristine SnO_(2).This simple scalable strategy has shown great promise toward highly efficient and stable PSCs.

Bilayer metal halide perovskite for efficient and stable solar cells and modules

To reach the target of carbon neutral,a transition from fossil energy to renewable energy is unavoidable.Photovoltaic technology is considered one of the most prominent sources of renewable energy.Recently,metal halide perovskite materials have attracted tremendous interest in the areas of optoelectronic devices due to their ease of processing and outstanding performance.To date,perovskite solar cells(PSCs)have shown high power conversion efficiency up to 25.7%and 31.3%for the perovskite-silicon tandem solar cells,which promises to revolutionize the PV landscape.However,the stability of PSCs under operating conditions has yet to match state-of-the-art silicon-based solar cell technology,in which the stability of the absorbing layer and relevant interfaces is the primary challenge.These issues become more serious in the larger area solar modules due to the additional interfaces and more defects within the perovskite.Bilayer perovskite film composed of a thin low dimensional perovskite layer and a three-dimensional perovskite layer shows great potential in fabricating solar cells with high efficiency and stability simultaneously.In this review,recent advancements,including composition design and processing methods for constructing bilayer perovskite films are discussed.We then analyze the challenges and resolutions in deposition bilayer perovskite films with scalable techniques.After summarizing the beneficial effect of the bilayer structure,we propose our thinking of feasible strategies to fabricate high efficiency perovskite solar modules with a long lifetime.Finally,we outline the directions for future work that will push the perovskite PV technology toward commercialization.