Temperature Dependent Crystallization Mechanisms of Methylammonium Lead Iodide Perovskite From Different Solvents

Hybrid perovskites are a novel type of semiconductors that show great potential for solution processed optoelectronic devices. For all applications, the device performance is determined by the quality of the solution processed perovskite thin films. During solution processing, the interaction of solvent with precursor molecules often leads to the formation of solvate intermediate phases that may diverge the crystallization pathway from simple solvent evaporation to a multi step formation process. We here investigate the crystallization of methylammonium lead iodide MAPbI 3 from a range of commonly utilized solvents, namely dimethyl sulfoxide DMSO , N,N dimethylformamide DMF , N methylpyrrolidone NMP , and gamma butyrolactone GBL at different temperatures ranging from 40 C to gt;100 C by in situ grazing incidence wide angle X ray scattering GIWAXS measurements. For all solvents but GBL, we clearly observe the formation of solvate intermediate phases at moderate processing temperatures. With increasing temperatures, an increasing fraction of the MAPbI 3 perovskite phase is observed to form directly. From the temperature dependence of the phase formation and phase decomposition rates, the activation energy to form the MAPbI 3 perovskite phase from the solvate phases are determined as a quantitative metric for the binding strength of the solvent within the solvate intermediate phases and we observe a trend of DMSO gt; DMF gt; NMP gt; GBL. These results enable prediction of processing temperatures at which solvent molecules can be effectively remove

Dependence of phase transitions on halide ratio in inorganic CsPb BrxI1 x 3 perovskite thin films obtained from high throughput experimentation

In this communication, we present the phase diagram of CsPb BrxI1 amp; 8722;x 3 0 amp; 8804; x amp; 8804; 1, 300 585 K obtained by high throughput in situ GIWAXS measurements of a combinatorial thin film library. We find that all compositions convert to the cubic perovskite phase at high temperature and that the presence of bromide in the films stabilizes the metastable perovskite phases upon cool down. In accordance with recent predictions from DFT calculations, the transition temperatures monotonically decrease with increasing bromide conten

Smooth anti reflective three dimensional textures for liquid phase crystallized silicon thin film solar cells on glass

Recently, liquid phase crystallization of thin silicon films has emerged as a candidate for thin film photovoltaics. On 10 amp; 956;m thin absorbers, wafer equivalent morphologies and open circuit voltages were reached, leading to 13.2 record efficiency. However, short circuit current densities are still limited, mainly due to optical losses at the glass silicon interface. While nano structures at this interface have been shown to efficiently reduce reflection, up to now these textures caused a deterioration of electronic silicon material quality. Therefore, optical gains were mitigated due to recombination losses. Here, the SMooth Anti Reflective Three dimensional SMART texture is introduced to overcome this trade off. By smoothing nanoimprinted SiOx nano pillar arrays with spin coated TiOx layers, light in coupling into laser crystallized silicon solar cells is significantly improved as successfully demonstrated in three dimensional simulations and in experiment. At the same time, electronic silicon material quality is equivalent to that of planar references, allowing to reach Voc values above 630 mV. Furthermore, the short circuit current density could be increased from 21.0 mA cm amp; 8722;2 for planar reference cells to 24.5 mA cm amp; 8722;2 on SMART textures, a relative increase of 18 . External quantum efficiency measurements yield an increase for wavelengths up to 700 nm compared to a state of the art solar cell with 11.9 efficiency, corresponding to a jsc, EQE gain of 2.8 mA cm amp; 8722;

Combinatorial inkjet printing for compositional tuning of metal halide perovskite thin films

To accelerate the materials discovery and development process for a sustainable technology advancement it is imperative to explore and develop combined high throughput material synthesis and analysis workflows. In this work, we investigate a method of combinatorial inkjet printing to tune the composition of the inorganic cesium lead mixed halide perovskite solid solution, CsPb BrxI1 amp; 8722;x 3. The compositional variation is achieved by simultaneous printing of different precursor inks with multiple printheads and controlled by varying the number of droplets printed by each printhead throughout the sample. The droplet placement is optimised through an algorithm that allows maximum mixing of the combined inks. The local compositional homogeneity of thin film samples was investigated as a function of the printing resolution by micrometer resolution X ray fluorescence and synchrotron based grazing incidence wide angle X ray scattering. We show that a combinatorial library of ten compositions between CsPbI3 and CsPbBr2I, printed using the developed algorithm, is locally homogeneous for the optimised printing parameters. An implementation of the algorithm in the high level programming language Python is provided for easy use in other system

Slot Die Coated Triple Halide Perovskites for Efficient and Scalable Perovskite Silicon Tandem Solar Cells

Wide bandgap halide perovskite materials show promising potential to pair with silicon bottom cells. To date, most efficient wide bandgap perovskites layers are fabricated by spin coating, which is difficult to scale up. Here, we report on slot die coating for an efficient, 1.68 eV wide bandgap triple halide 3halide perovskite absorber, Cs0.22FA0.78 Pb I0.85Br0.15 3 5 mol MAPbCl3. A suitable solvent system is designed specifically for the slot die coating technique. We demonstrate that our fabrication route is suitable for tandem solar cells without phase segregation. The slot die coated wet halide perovskite is dried by a nitrogen N2 knife with high reproducibility and avoiding antisolvents. We explore varying annealing conditions and identify parameters allowing crystallization of the perovskite film into large grains reducing charge collection losses and enabling higher current density. At 150 C, an optimized trade off between crystallization and the PbI2 aggregates on the film s top surface is found. Thus, we improve the cell stability and performance of both single junction cells and tandems. Combining the 3halide top cells with a 120 amp; 956;m thin saw damage etched commercial Czochralski industrial wafer, a 2 terminal monolithic tandem solar cell with a PCE of 25.2 on a 1 cm2 active area is demonstrated with fully scalable processe

An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles

Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42,400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences

An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles

Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42, 400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences. © 2021, The Author(s)

Roadmap on organic inorganic hybrid perovskite semiconductors and devices

Metal halide perovskites are the first solution processed semiconductors that can compete in their functionality with conventional semiconductors, such as silicon. Over the past several years, perovskite semiconductors have reported breakthroughs in various optoelectronic devices, such as solar cells, photodetectors, light emitting and memory devices, and so on. Until now, perovskite semiconductors face challenges regarding their stability, reproducibility, and toxicity. In this Roadmap, we combine the expertise of chemistry, physics, and device engineering from leading experts in the perovskite research community to focus on the fundamental material properties, the fabrication methods, characterization and photophysical properties, perovskite devices, and current challenges in this field. We develop a comprehensive overview of the current state of the art and offer readers an informed perspective of where this field is heading and what challenges we have to overcome to get to successful commercializatio

An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles

AbstractLarge datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42,400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences.</jats:p

In situ graphene doping as a route toward efficient perovskite tandem solar cells

Tandem solar cells consisting of perovskite and silicon absorbers have the potential to outperform respective state of the art single junction efficiencies. However, their development requires the gentle deposition of a transparent electrode onto the hybrid perovskite and its organic layers. Implementation of large area graphene obtained by chemical vapor deposition seems to be an excellent solution. In this paper, we present the impact of graphene on perovskite solar cells and their organic layers. Direct application of graphene on CH3NH3PbI3 is limited by a highly defective interface but insertion of spiro OMeTAD enables a defect free implementation. Solar cells containing transparent graphene contacts approach identical electrical performance compared to devices with standard Au contacts. Hall effect measurements of graphene on various organic thin films, revealed the importance of field effect doping. Gained knowledge enabled the development of a strategy to increase the charge carrier density in graphene by 60 , while lowering graphene sheet resistance by 24 . This combined route of spiro OMeTAD and stabilized adsorbent doping is an important step toward the targeted application in high performance monolithic perovskite silicon tandem solar cell