Dimethylamine oxalate manipulating CsPbI_(3) perovskite film crystallization process for high efficiency carbon electrode based perovskite solar cells

Crystallization process determines the quality of perovskite films and the performances of resultant perovskite solar cells(PSCs).Dimethylamine oxalate has been proven as a multifunctional modulator,and is explored as an efficient additive in manipulating the crystallization process of CsPbI_(3) perovskite films.On one hand,oxalate serves as the precipitator that facilitates the nucleation process of intermediate.The larger size of intermediate is conductive to the larger size and smaller grain boundaries of resultant perovskite.On the other hand,in subsequent annealing process,the phase conversion and growth process of transient perovskite can be decelerated due to the strong interactions of oxalate with both dimethylamine cation(DMA^(+))and Pb^(2+).Due to the optimized crystallization kinetics,the morphology and quality of CsPbI_(3) perovskite films are comprehensively improved with lower defect concentrations,and charge recombination loss is effectively suppressed.Benefiting from the optimized crystal quality of perovskite films,the carbon electrode-based CsPbI_(3) PSCs exhibit a champion efficiency of 18.48%.This represents one of the highest levels among all hole transport layer-free inorganic perovskite solar cells.

Modification of compact TiO_(2) layer by TiCl_(4)-TiCl_(3) mixture treatment and construction of high-efficiency carbon-based CsPbI_(2)Br perovskite solar cells

In the construction of high performance planar perovskite solar cells(PSCs),the modification of compact TiO_(2) layer and engineering of perovskite/TiO_(2) interfaces are essential for efficient electron transfer and retarded charge recombination loss.In this work,a facile and effective strategy is developed to modify the surface of compact TiO_(2) layer by TiCl_(4)-TiCl_(3) mixture treatment.Compared with conventional sole TiCl_(4),the TiCl_(4)-TiCl_(3) treatment takes the advantage of accelerated and controlled hydrolysis of TiCl_(3),therefore TiO_(2) with dominating anatase phase and moderate roughness is obtained to facilitate the growth of CsPbI_(2) Br perovskite layer with high quality.Furthermore,the oxidation-driven hydrolysis of TiCl_(3) component results in surface Cl doping that facilitates interfacial electron transfer with retarded recombination loss.The average power conversion efficiency(PCE) of carbon-based CsPbI_(2) Br planar PSCs based on TiCl_(4)-TiCl_(3) treatment increases to 14.18% from the intial 13.04% based on conventional sole TiCl_(4) treatment.The champion PSC exhibits a PCE of 14.46%(V_(oc)=1.28 V,J_(sc)=14.21 mA/cm^(2),and FF=0.794),which is one of the highest PCEs for carbon-based CsPbI_(2) Br PSCs.

Selenium cooperated polysulfide electrolyte for efficiency enhancement of quantum dot-sensitized solar cells

The modification of polysulfide electrolyte with additives has been demonstrated as an effective way to improve the photovoltaic performance of quantum dot-sensitized solar cells(QDSCs). Most of these additives can inhibit the charge recombination processes at photoanode/electrolyte interface and favor the improvement of V oc of cell devices. Herein, we showed that the incorporation of elemental selenium(Se) in polysulfide electrolyte to form polyselenosulfide species can notably improve the performance of QDSCs. Unlike previous reports, we present here an integrated investigation of the effects of polyselenosulfide species in polysulfide electrolyte on the photovoltaic performance of QDSCs from both of the photoanode and counter electrode(CE) aspects. Electrochemical impedance spectroscopy(IS) and opencircuit voltage-decay(OCVD) measurements demonstrated that the introduction of Se into polysulfide electrolyte can not only retard charge recombination at photoanode/electrolyte interface, but also reduce the charge transfer resistance at CE/electrolyte interface, resulting in the improvement of J sc and FF values. Consequently, the average efficiency of Zn-Cu-In-Se QDSCs was improved from 9.26% to 9.78% under AM 1.5 G full one sun illumination.

Interpenetrating structure for efficient Sb_(2)Se_(3) nanorod array solar cells loaded with CuInSe_(2) QDs sensitizer

The strong anisotropic electrical properties of one-dimensional(1 D) nanostructure semiconductors,especially the anisotropic carrier transport, have a negative and significant influence on the performance of solar cells if the nanostructures have random orientation. Considering the advantages of nanorod solar cells in carrier transport, we have achieved growth of vertically aligned Sb_(2)Se_(3) nanorod array with highly(hk1) orientation on Cd S substrate, and constructed superstrate nanorod solar cells for the first time. The Sb_(2)Se_(3) nanorod array solar cells exhibit the more efficient and long-range carrier transport in vertical direction. Furthermore, in order to suppress interface recombination, a CuInSe_(2) quantum dots(QDs) sensitizer has been applied to fill the volume between the nanorods completely, thus forming an interpenetrating nanocomposite structure. The CuInSe_(2) QDs can harvest additional light by absorption of visible light and contribute photocurrent. Meantime, the QDs function as a hole transport material and thus reduce the dependence of lateral transport. Consequently, the interpenetrating nanocomposite CuInSe_(2) / Sb_(2)Se_(3) solar cells display a power conversion efficiency of 7.54% with significant enhancements in the short-circuit current density and open-circuit voltage over pure Sb_(2)Se_(3) nanorod cells. This is the highest efficiency for superstrate solar cells based on Sb_(2)Se_(3) nanorod arrays.

Recent Development of Quantum Dot Deposition in Quantum Dot-Sensitized Solar Cells

As new-generation solar cells,quantum dot-sensitized solar cells(QDSCs)have the outstanding advantages of low cost and high theoretical efficiency;thus,such cells receive extensive research attention.Their power conversion efficiency(PCE)has increased from 5%to over 15%in the past decade.However,compared with the theoretical efficiency(44%),the PCE of QDSCs still needs further improvement.The low loading amount of quantum dots(QDs)is a key factor limiting the improvement of cell efficiency.The loading amount of QDs on the surface of the substrate film is important for the performance of QDSCs,which directly affects the light-harvesting ability of the device and interfacial charge recombination.The optimization of QD deposition and the improvement of the loading amount are important driving forces for the rapid development of QDSCs in recent years and a key breakthrough in future development.In this paper,the research progress of QD deposition on the surface of substrate films in QDSCs was reviewed.In addition,the main deposition methods and their advantages and disadvantages were discussed,and future research on the further increase in loading amount was proposed.

碳纳米管/聚三己基噻吩复合材料增强空穴提取助力碳基CsPbI_(2)Br太阳电池实现新的记录效率

碳基钙钛矿太阳电池(C-PSCs)具有低成本和高稳定性的优势,这归因于碳电极的化学惰性和疏水性.然而,C-PSCs的光伏性能通常低于相应的金属电极器件,其中最重要的原因是钙钛矿层和碳电极之间低的空穴提取效率.这里,我们发展了一种基于碳纳米管/聚三己基噻吩(CNT/P3HT,CP)复合材料的空穴传输材料用于构建C-PSCs.P3HT和CNTs之间的强相互作用力增强了P3HT的结晶度,同时也改善了CNTs的分散性.相比于纯P3HT,CP复合材料中的CNT提供了空穴传输的高速通道,进而有效地降低电荷传输阻抗和改善空穴提取效率.这种CP复合材料被用于组装CsPbI_(2)Br C-PSCs,其光电压由1.233 V提高到1.355 V,能量转换效率也由13.29%提高到15.56%,刷新了碳基全无机钙钛矿太阳电池的记录.

Self-supported metal sulphide nanocrystals-assembled nanosheets on carbon paper as efficient counter electrodes for quantum-dotsensitized solar cells

Developing efficient counter electrodes(CEs)and quantum dots made of earth-abundant and non-toxic elements is essential but still challenging for quantum dot-sensitized solar cells(QDSSCs).Here,we report a facile strategy to prepare self-supported and robust CoS_2and NiS nanocrystals-assembled nanosheets directly grown on carbon paper(MS_xNS@CP)as efficient counter electrodes for QDSSCs.Such CEs integrate the merits of fast electron transfer from interconnected conductive scaffold,efficient mass transfer from hierarchically vertical nanosheet on 3D open substrate,as well as abundant highly active catalytic sites from metal sulphide nanocrystal units.As a result,QDDSCs based on such CoS_2NS@CP and NiS NS@CP CEs achieve a PCE of8.88%and 7.53%,respectively.The detailed analyses suggest that CoS_2NS@CP has the highest catalytic activity and shows the lowest charger transfer resistance,leading to the highest PCE.These findings may inspire the design and exploration of other self-supported efficient CEs by integrating highly active catalysts onto 3D conductive networks for efficient QDSSCs.