钙钛矿太阳能电池技术发展历史与现状

简要回顾了钙钛矿太阳能电池的发展历史,解释了钙钛矿太阳能电池本质上是固态染料敏化太阳能电池。介绍了钙钛矿太阳能电池的微观发电机理,结合钙钛矿太阳能电池的能级图分析讨论了钙钛矿与电子传输层和空穴传输层的能级匹配。分析总结了钙钛矿太阳能电池的光伏技术参数,包括光生电流密度、开路电压、填充因子、能量转换效率以及光伏性能的稳定性。钙钛矿太阳能电池的能量转换效率、短路电流密度和开路电压均已超过非晶硅薄膜太阳能电池,填充因子与非晶硅薄膜太阳能电池很接近。钙钛矿太阳能电池有希望实现产业化而成为下一代薄膜太阳能电池。指出了钙钛矿太阳能电池大规模市场应用在制造技术上的瓶颈即空穴传输层的造价昂贵,并综述了解决该瓶颈的最新研究工作。     

Pt/Y<Subscript>2</Subscript>O<Subscript>3</Subscript>:Eu<Superscript>3+</Superscript> composite nanotubes: Enhanced photoluminescence and application in dye-sensitized solar cells

Y(OH)3:Eu3+ nanotubes were synthesized using a facile hydrothermal method,and then,Pt particles were grown on the surface of the nanotubes using a combination of vacuum extraction and annealing.The resulting Pt/Y2O3∶Eu3+ composite nanotubes not only exhibited enhanced red luminescence under 255-or 468-nm excitation but could also be used to improve the efficiency of dyesensitized solar cells,resulting in an efficiency of 8.33％,which represents a significant enhancement of 11.96％ compared with a solar cell without the composite nanotubes.Electrochemical impedance spectroscopy results indicated that the interfacial resistance of the TiO2-dye|I3-/I-electrolyte interface of the TiO2-Pt/Y2O3:Eu3+ composite cell was much smaller than that of a pure TiO2 cell.In addition,the TiO2-Pt/Y2O3:Eu3+ composite cell exhibited a shorter electron transport time and longer electron recombination time than the pure TiO2 cell.     

Influence of SCN− moiety on CH3NH3PbI3 perovskite film properties and the performance of carbon-based hole-transport-layer-free perovskite solar cells

Journal of Materials Science: Materials in Electronics - CH3NH3PbI3 perovskite films were prepared via a hot-casting method using six different CH3NH3I, PbI2 and Pb(SCN)2 solutions. Surface...     

不同炭黑对钙钛矿太阳能电池性能的影响

本文研究了四种炭黑(Cabot Vulan XC-72(CVXC-72),XFI15,Ketjen EC-300J(EC300J),Ketjen EC-300JD(EC300JD))对碳对电极及其制备的电池性能的影响。研究结果表明:以EC-300J为基础制备的碳对电极导电性最好且其与CH3NH3PbI3前驱体溶液具有较好的润湿性,基于这种炭黑制备的电池器件得到了4.88%的光电转换效率,并具有较好的稳定性。     

基于热饱和溶液法CH3NH3PbI3单晶的制备及表征

采用热饱和溶液法,通过调控前驱体溶液1,4-丁内酯中PbI2和CH3NH3I的配比,进而对前驱液100℃进行加热,简单易操作地得到单晶CH3NH3PbI3。计算了不同调控条件下单晶CH3NH3PbI3的产率;利用SEM和XRD对其形貌和结晶度进行表征;通过吸收和荧光光谱对单晶的光谱性能进行表征。结果表明,单晶CH3NH3PbI3的最佳摩尔配比为n(PbI2)∶n(CH3NH3I)=2.3∶1,PbI2最佳浓度为1.229 mmol/mL。     

Effective Improvement of the Photovoltaic Performance of Carbon-Based Perovskite Solar Cells by Additional Solvents

Nano-Micro Letters - A solvent-assisted methodology has been developed to synthesize CH3NH3PbI3 perovskite absorber layers. It involved the use of a mixed solvent of CH3NH3I, PbI2,...     

Unravelling charge carrier dynamics in protonated g-C<Subscript>3</Subscript>N<Subscript>4</Subscript> interfaced with carbon nanodots as co-catalysts toward enhanced photocatalytic CO<Subscript>2</Subscript> reduction: A combined experimental and first-principles DFT study

In this work,we demonstrated the successful construction of metal-free zerodimensional/two-dimensional carbon nanodot (CND)-hybridized protonated g-C3N4 (pCN) (CND/pCN) heterojunction photocatalysts by means of electrostatic attraction.We experimentally found that CNDs with an average diameter of 4.4 nm were uniformly distributed on the surface of pCN using electron microscopy analysis.The CND/pCN-3 sample with a CND content of 3 wt.％ showed the highest catalytic activity in the CO2 photoreduction process under visible and simulated solar light.Thisprocess results in the evolution of CH4 and CO.The total amounts of CH4 and CO generated by the CND/pCN-3 photocatalyst after 10 h of visible-light activity were found to be 29.23 and 58.82 μmol·gcatalyst-1,respectively.These values were 3.6 and 2.28 times higher,respectively,than the amounts generated when using pCN alone.The corresponding apparent quantum efficiency (AQE) was calculated to be 0.076％.Furthermore,the CND/pCN-3 sample demonstrated high stability and durability after four consecutive photoreaction cycles,with no significant decrease in the catalytic activity.The significant improvement in the photoactivity using CND/pCN-3 was attributed to the synergistic interaction between pCN and CNDs.This synergy allows the effective migration of photoexcited electrons from pCN to CNDs via wellcontacted heterojunction interfaces,which retards the charge recombination.This was confirmed by photoelectrochemical measurements,and steady-state and time-resolved photoluminescence analyses.The first-principles density functional theory (DFT) calculations were consistent with our experimental results,and showed that the work function of CNDs (5.56 eV) was larger than that of pCN (4.66 eV).This suggests that the efficient shuttling of electrons from the conduction band of pCN to CNDs hampers the recombination of electron-hole pairs.This significantly increased the probability of free charge carriers reducing CO2 to CH4 and CO.Overall,this study underlines the importance of understanding the charge carrier dynamics of the CND/pCN hybrid nanocomposites,in order to enhance solar energy conversion.     

Photoelectric Parameters of Photodetectors Based on Thin Microcrystalline Films of CH3NH3PbI3 Perovskite

Technical Physics Letters - Photoelectric characteristics of photodetectors of the type of a photoresistor based on microcrystalline films of the organometallic perovskite CH3NH3PbI3 with gold and...     

稀土上转换发光在钙钛矿太阳能电池中的应用

目前,钙钛矿太阳能电池最常使用的钙钛矿材料为CH_3NH_3PbI_3,其禁带宽度为1.55eV,导致低于该能量值的太阳光的光子无法被直接地吸收利用。因此,提高器件对太阳光谱的响应范围是提高钙钛矿太阳能电池性能的关键。稀土上转换材料可以将低能量近红外光转换为高能量可见光,所以,稀土上转换发光的应用是提高钙钛矿太阳能电池性能的较为可行的途径。本文概述了稀土上转换发光的基本机制,介绍了钙钛矿太阳能电池的结构和工作原理,综述了该太阳能电池的研究现状及其主要优势,重点阐述了稀土上转换发光在钙钛矿太阳能电池中的应用,最后对该太阳能电池的发展前景进行了展望。     

Enhanced stability and efficiency of Sn containing perovskite solar cell with SnCl<Subscript>2</Subscript> and SnI<Subscript>2</Subscript> precursors

Presence of toxic Pb and device stability are the main issues with perovskite solar cell. For Pb replacement, most likely substitute is Sn, which is a metal of group 14 (like Pb). Thus, in the present study, the amount of Pb is reduced and replaced by Sn. To achieve the replacement, use of SnCl₂ is explored in addition to generally used precursor (SnI₂), as the source of Sn. Molar ratio of PbI₂:SnCl₂/SnI₂ is varied to get optimum performance of perovskite solar cell. Pt–FTO counter electrode is used in addition to spiro-MeTAD (as hole transport material). The power conversion efficiency of solar cells containing 2:2 molar ratio of PbI₂:SnCl₂ was enhanced to 10.10%, and PbI₂:/SnI₂ was enhanced to 10.61%. Without Sn addition (CH₃NH₃PbI₃) the efficiency was only 7.39%. The clear enhancement of 37% (SnCl₂) and 43% (SnI₂) is highly encouraging, as it leads to less toxic and highly efficient solar cells at the same time. In addition, the percentage loss in power conversion efficiency of device prepared with SnCl₂ (CH₃NH₃Pb_0.5Sn_0.5ICl₂) was also superior (10 days).     

Efficient light harvesting from flexible perovskite solar cells under indoor white light-emitting diode illumination

This is the first report of an investigation on flexible perovskite solar cells for artificial light harvesting by using a white light-emitting diode (LED) lamp as a light source at 200 and 400 lx,values typically found in indoor environments.Flexible cells were developed using either low-temperature sol-gel or atomiclayer-deposited compact layers over conducting polyethylene terephthalate (PET)substrates,together with ultraviolet (UV)-irradiated nanoparticle TiO2 scaffolds,a CH3NH3PbI3-xClx perovskite semiconductor,and a spiro-MeOTAD hole transport layer.By guaranteeing high-quality carrier blocking (via the 10-40 nm-thick compact layer) and injection (via the nanocrystalline scaffold and perovskite layers) behavior,maximum power conversion efficiencies (PCE) and power densities of 10.8％ and 7.2 μW.cm-2,respectively,at 200 lx,and 12.1％ and 16.0 μW·cm-2,respectively,at 400 lx were achieved.These values are the state-of-the-art,comparable to and even exceeding those of flexible dye-sensitized solar cells under LED lighting,and significantly greater than those for flexible amorphous silicon,which are currently the main flexible photovoltaic technologies commercially considered for indoor applications.Furthermore,there are significant margins of improvement for reaching the best levels of efficiency for rigid glass-based counterparts,which we found was a high of PCE ～24％ at 400 lx.With respect to rigid devices,flexibility brings the advantages of being low cost,lightweight,very thin,and conformal,which is especially important for seamless integration in indoor environments.     

Dielectric characteristics of Pb(Zn<Subscript>1/3</Subscript>Ta<Subscript>2/3</Subscript>)O<Subscript>3</Subscript>-BaTiO<Subscript>3</Subscript> ceramics with/without PbTiO<Subscript>3</Subscript> modification

Stabilization tendencies of the perovskite structure in a Pb(Zn_1/3Ta_2/3)O₃-BaTiO₃ pseudobinary system with/without compositional modification by 20 mol% PbTiO₃ introduction were compared. In order to promote perovskite phase formation, the B-site precursor method (which is conceptually similar to the columbite process) was employed in this study. Dielectric properties of sintered samples were investigated as functions of composition and measurement frequency. Dielectric constant spectra, in the paraelectric temperature region, were further analyzed in terms of diffuseness. Microstructures of sintered specimens were also investigated and correlated with perovskite stabilization.     

Structural and Magnetic Properties of La<Subscript>2/3</Subscript>Sr<Subscript>1/3</Subscript>MnO<Subscript>3</Subscript>/SrTiO<Subscript>3</Subscript>/CoFe<Subscript>2</Subscript> Hard-Soft Magnetic Systems

We report on the growth and magnetic properties of La_2/3Sr_1/3MnO₃/SrTiO₃/CoFe₂ hard-soft magnetic systems prepared by pulsed laser deposition on SrTiO₃(001) substrates. In situ reflection high-energy electron diffraction along the [100]SrTiO₃ substrate azimuth and atomic force microscopy measurements reveal that La_2/3Sr_1/3MnO₃ and SrTiO₃ grow both in a three dimensional mode and that the roughness of the lower and upper magnetic/non-magnetic interfaces ranges between 2 and 4 Å. Cross-section transmission electron microscopy observations show that the layers are continuous, with an homogeneous thickness, and that the interfaces are mostly sharp and correlated. The magnetization curves show a two step reversal of the magnetization, with very distinct coercive fields. A small anisotropy is observed for the CoFe₂ layer with an in plane easy magnetization axis along the [110]SrTiO₃ direction. Minor magnetization loops indicate that the coupling between the magnetic layers is negligible.     

Dielectric responses in Mg<Subscript>1/3</Subscript>Ta<Subscript>2/3</Subscript>-replaced Pb[(Zn<Subscript>1/3</Subscript>Nb<Subscript>2/3</Subscript>),Ti]O<Subscript>3</Subscript> ceramics

Octahedral lattice sites of Pb[(Zn_1/3Nb_2/3),Ti]O₃ were replaced by 20 at.% Mg_1/3Ta_2/3 complex to enhance perovskite development, especially at Pb(Zn_1/3Nb_2/3)O₃-rich compositions. Resultant changes in the perovskite formation and associated dielectric responses were investigated. A perovskite structure was identified at Pb(Zn_1/3Nb_2/3)O₃-rich compositions by X-ray diffraction, although the development was rather incomplete. Phase transition modes in the dielectric constant spectra changed from diffuse to sharp ones, regardless of the introduction of Mg_1/3Ta_2/3. Dielectric maximum temperatures of the ceramics shifted linearly with the compositional change.     

基于对氯苄胺的2D/3D钙钛矿太阳能电池

三维(3D)有机–无机金属卤化物钙钛矿薄膜的表面和晶界处存在大量缺陷,容易导致载流子的非辐射复合并加快3D钙钛矿分解,进而影响钙钛矿太阳能电池(PSCs)能量转换效率(PCE)及稳定性.本研究通过引入对氯苄胺阳离子,与3D钙钛矿薄膜及其表面过剩的碘化铅反应后原位形成了二维(2D)钙钛矿,实现了对3D钙钛矿薄膜表面和晶界...     

Role of Ti diffusion on the formation of phases in the Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–Al<Subscript>2</Subscript>O<Subscript>3</Subscript> brazed interface

Diffusivities of Ti, Cu, Al and Ag in the interface of Al₂O₃–Al₂O₃ braze joints using Ag–Cu–Ti active filler alloy, have been calculated by Matano–Boltzman method. The Matano plane has been identified for each elemental diffusion at various brazing temperatures. The diffusivities of Ag, Cu and Al are almost insignificant on formation of interface during brazing, whereas the diffusivity of Ti changes significantly with the brazing temperature and controls the formation of different reaction product in the interface. Presence of TiO and Ti₃Cu₃O phases in the interface has been confirmed by transmission electron microscopy (TEM).     

Interface roughness influence on exchange bias effect in La<Subscript>2/3</Subscript>Ca<Subscript>1/3</Subscript>MnO<Subscript>3</Subscript>/La<Subscript>1/3</Subscript>Ca<Subscript>2/3</Subscript>MnO<Subscript>3</Subscript> bilayers

A Monte Carlo simulation study of La_2/3Ca_1/3MnO₃/La_1/3Ca_2/3MnO₃ bilayers exchange bias (EB) properties by using a classical Heisenberg model and Monte Carlo method with Metropolis algorithm is addressed. Samples were built atom-by-atom in order to resemble the real roughness. In this model, several contributions included nearest neighbors exchange interactions; two different interface couplings, magnetocrystalline anisotropy and Zeeman term, were considered. Here, an influence of the relaxation steps on the interface roughness is present. Our study focuses on the influence of interface roughness on hysteresis loops, particularly EB field (H _ex) and coercive force (H _c). Results reveal that H _ex and H _c decrease as the interface roughness increases.     

Trash into Treasure: δ‐FAPbI3 Polymorph Stabilized MAPbI3 Perovskite with Power Conversion Efficiency beyond 21%

Effective passivation and stabilization of both the inside and interface of a perovskite layer are crucial for perovskite solar cells (PSCs), in terms of efficiency, reproducibility, and stability. Here, the first formamidinium lead iodide (δ‐FAPbI₃) polymorph passivated and stabilized MAPbI₃ PSCs are reported. This novel MAPbI₃/δ‐FAPbI₃ structure is realized via treating a mixed organic cation MA _x FA_{1‐ x} PbI₃ perovskite film with methylamine (MA) gas. In addition to the morphology healing, MA gas can also induce the formation of δ‐FAPbI₃ phase within the perovskite film. The in situ formed 1D δ‐FAPbI₃ polymorph behaves like an organic scaffold that can passivate the trap state, tunnel contact, and restrict organic‐cation diffusion. As a result, the device efficiency is easily boosted to 21%. Furthermore, the stability of the MAPbI₃/δ‐FAPbI₃ film is also obviously improved. This δ‐FAPbI₃ phase passivation strategy opens up a new direction of perovskite structure modification for further improving stability without sacrificing efficiency.     

Photoelectrochemical properties of lead-free ferroelectric ceramic Ba(Ti<Subscript>0.96</Subscript>Mg<Subscript>0.013</Subscript>Nb<Subscript>0.026</Subscript>)O<Subscript>3</Subscript>: application to solar conversion of eosin

The lead-free Ba(Ti_0.96Mg_0.013Nb_0.026)O₃ composition has been prepared by solid state reaction. The room temperature X-ray diffraction revealed a perovskite phase with a tetragonal symmetry. The complex dielectric permittivity measured on cooling from 470 to 150 K in the frequency range (10²–10⁶ Hz) indicated a ferroelectric behavior and exhibited a large electromechanical response. This ferroelectric perovskite showed photoelectrochemical properties with an optical gap of 2.90 eV, n-type conduction and a flat band potential of ?0.57 V _SCE . As application, the oxide is successfully tested for the eosin oxidation under solar light. At pH ~ 6.3, 90 % of eosin (15 mg L^?1) disappeared after 6 h of illumination for a catalyst dose of 2.5 g L^?1.     

Pt effects in γ-Ni(Al)/α-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> adhesion

We present a systematic first-principles density-functional theory (DFT) study of the effects of Pt on the adhesion of the γ-Ni(Al)/α-Al₂O₃ interface, in a close comparison with those of Hf and S. Both the thermodynamically preferred Al-rich and the stoichiometric interfaces are considered. S is found to segregate to and substantially weaken both interfaces. Hf can pin S in bulk γ-Ni even at temperatures as high as 1,600 K, effectively inhibiting S segregation, while Pt cannot, due to phonon effects. For the stronger, Al-rich interface, both Hf and Pt have larger heats of segregation than S, inhibiting S segregation through preferential segregation. For the weaker, stoichiometric interface, Hf can significantly strengthen its adhesion to be as large as that of the Al-rich interface, and also inhibit S segregation through preferential segregation. Pt, as a contrast, can neither inhibit S segregation nor directly enhance the interface bonding.