Preparation Of Solar Cells Research Articles

Comprehensive Innovation Experiment: Preparation and Characterization of Carbon-based Perovskite Solar Cells

Comprehensive Innovation Experiment: Preparation and Characterization of Carbon-based Perovskite Solar Cells

Methanol as an anti-solvent to improve the low open-circuit voltage of CsPbBr3 perovskite solar cells prepared with water.

CsPbBr3 has received more and more attention in the field of optoelectronic devices due to its excellent stability. To address the cost and environmental concerns associated with the use of toxic methanol, water has been explored as a substitute solvent for CsBr in the preparation of CsPbBr3 perovskite solar cells (PSCs). In this study, we utilized methanol as an anti-solvent of the CsBr/H2O solution to regulate the detrimental effects of water on the CsPbBr3 film and control the crystallization process. From results of the experiment, it was found that methanol anti-solvent treatment greatly improved the crystallization of the CsPbBr3 film, increased the grain size, and reduced the defect density. After the introduction of methanol anti-solvent treatment, the power conversion efficiency (PCE) increased from 6.09% to 7.91%, while the open-circuit voltage (Voc) increased from 1.18 V to 1.39 V. Furthermore, we incorporated 2-hydroxyethylurea into the CsPbBr3 PSCs to improve the wettability of PbBr2 towards the CsBr/H2O solution and ensure the formation of pure-phase CsPbBr3 films. The introduction of 2-hydroxyethylurea resulted in an additional increase in Voc from 1.19 V to 1.42 V. The PCE further improved from 6.56% to 8.62% after methanol anti-solvent treatment. These results demonstrate that methanol treatment effectively addresses the low Voc issue observed in CsPbBr3 PSCs prepared with water as a solvent. Importantly, this approach significantly reduces the reliance on methanol compared to conventional fabrication methods for CsPbBr3 PSCs. Overall, this work presents a promising pathway for achieving high Voc and efficiency in CsPbBr3 PSCs by utilizing water as a solvent.

Improvement of performance of perovskite solar cells through BaTiO<sub>3</sub> doping regulated built-in electric field

The preparation of hybrid perovskite solar cells is expensive and environmentally demanding. Carbon-based HTL-free perovskite solar cells (C-PSCs) have attracted much attention because they replace the expensive precious metal electrode and remove the poor stability of the hole transport material. However, the improvement of efficiency is hampered by poor carrier separation and transport performance within C-PSCs, while the enhancement of the built-in electric field can improve the carrier transport performance, thus enhancing photoelectric performance. The built-in electric field can be regulated by doping. The anomalous photovoltaic effect and the built-in electric field of ferroelectric material play an important role in the field of optoelectronics. In this work, a simple and effective method is developed to improve the performance of perovskite solar cells via the combination of internal doping of ferroelectric polymer and external control of electric field. Ferroelectric material barium titanate (BaTiO<sub>3</sub>) powder is added into perovskite precursor solution as an additive to prepare C-PSCs, which can improve the perovskite film morphology, reduce the film defect density, and enhance the carrier transport performance of C-PSCs. The results show that when the addition of BaTiO<sub>3</sub> is 1.0% (mass fraction), the perovskite film is uniform and dense, and the photoelectric conversion efficiency of the cell is the highest. After the forward voltage polarization treatment, the residual polarized electric field of ferroelectric material BaTiO<sub>3</sub> increases the built-in electric field, which provides sufficient power for realizing carrier transport and extraction, thus inhibiting the occurrence of non-radiative recombination. At the same time, the depletion layer width is increased, and the reverse saturation current is reduced, so the cell performance is significantly improved. The optimal device efficiency is 9.02%. This work provides an efficient strategy for regulating the built-in electric field by doping perovskite absorption layer.

Preparation of Dye-Sensitized Solar Cell With Modification of Photoanode by g-C3N4/NiS/TiO2 Nanofibers and Its Performance Under Outdoor and Indoor Illumination

Preparation of Dye-Sensitized Solar Cell With Modification of Photoanode by g-C₃N₄/NiS/TiO₂ Nanofibers and Its Performance Under Outdoor and Indoor Illumination

Synchronous Elimination of Excess Photoinstable PbI2 and Interfacial Band Mismatch for Efficient and Stable Perovskite Solar Cells.

Eliminating the undesired photoinstability of excess lead iodide (PbI2 ) in the perovskite film and reducing the energy mismatch between the perovskite layer and heterogeneous interfaces are urgent issues to be addressed in the preparation of perovskite solar cells (PVSCs) by two-step sequential deposition method. Here, the 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4 ) is employed to convert superfluous PbI2 to more robust 1D EMIMPbI3 which can withstand lattice strain, while forming an interfacial dipole layer at the SnO2 /perovskite interface to reconfigure the interfacial energy band structure and accelerate the charge extraction. Consequently, the unencapsulated PVSCs device attains a champion efficiency of 24.28 % with one of the highest open-circuit voltage (1.19 V). Moreover, the unencapsulated devices showcase significantly improved thermal stability, enhanced environmental stability and remarkable operational stability accompanied by 85 % of primitive efficiency retained over 1500 h at maximum power point tracking under continuous illumination.

Synchronous Elimination of Excess Photoinstable PbI2 and Interfacial Band Mismatch for Efficient and Stable Perovskite Solar Cells

AbstractEliminating the undesired photoinstability of excess lead iodide (PbI2) in the perovskite film and reducing the energy mismatch between the perovskite layer and heterogeneous interfaces are urgent issues to be addressed in the preparation of perovskite solar cells (PVSCs) by two‐step sequential deposition method. Here, the 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIMBF4) is employed to convert superfluous PbI2 to more robust 1D EMIMPbI3 which can withstand lattice strain, while forming an interfacial dipole layer at the SnO2/perovskite interface to reconfigure the interfacial energy band structure and accelerate the charge extraction. Consequently, the unencapsulated PVSCs device attains a champion efficiency of 24.28 % with one of the highest open‐circuit voltage (1.19 V). Moreover, the unencapsulated devices showcase significantly improved thermal stability, enhanced environmental stability and remarkable operational stability accompanied by 85 % of primitive efficiency retained over 1500 h at maximum power point tracking under continuous illumination.

Multifunctional Regulation of SnO2 Nanocrystals by Snail Mucus for Preparation of Rigid or Flexible Perovskite Solar Cells in Air.

Tin oxide (SnO2) is widely used as an inorganic electron transport layer (ETL) for rigid and flexible perovskite solar cells (PSCs). In this work, an extract of snail shell, the sodium salt of polyaspartic acid (S-PASP), a water-soluble polypeptide polymer, has been used to multifunctionally regulate SnO2 nanograins. S-PASP has a strong chelating and dispersing effect; thus, chemically adsorbed SnO2 can inhibit agglomeration. The S-PASP:SnO2 ETL also improved the extraction and transferability of carriers, reducing body defects and interfacial charge. Moreover, the S-PASP:SnO2 ETL promotes the vertical growth of the perovskite crystals due to its bottom-up morphology, wettability, and strain release, which is conducive to improving the photoelectric performance of the device. The optimized rigid device prepared under open-air conditions obtained a PCE of 20.92%. In addition, due to the stress compensation of the S-PASP long chain, which prevented the cracking and displacement of the ETL, the optimal PCE of the flexible device was 17.96%, and the initial efficiency was maintained at 82.8% after 100 bends. This work introduces a molecular doping mechanism for organic-inorganic hybrid electronics.

Multistep optimization for the electrodeposited mixed perovskite FA1−y Cs y PbBr x I3−x solar cells

The electrodeposition method has recently been developed for the fabrication of perovskite solar cells due to its potential advantages in commercial preparation. However, there is few studies on the preparation of perovskite solar cells by the electrodeposition method, especially on the perovskite FAPbI3-based solar cells. Herein, we fabricated the mixed perovskite FA1−y Cs y PbBr x I3−x solar cells by an optimized electrodeposition method, in which the electrodeposited PbO2 reacts directly with FAI and an appropriate amount of CsBr dopants. The corresponding solar cells display the best PCE of 4.97%. By regulating the growth temperature in the reaction between PbO2 and FAI/CsBr, the efficiency of the mixed perovskite solar cells can be promoted to 10.18%. These results illustrate that the element doping and growth environment regulation can optimize the quality of the perovskite films, thus promoting the efficiency of the perovskite solar cells. With further optimizing the growth process in the electrodeposition method, it is expected to open up a new commercial preparation route for the perovskite solar cells in the near future.

Sulfur-bridged oxotitanium phthalocyanine- and porphyrin-based cocktail dyes as sensitizers for improved dye sensitized solar cell efficiency

Effective non-symmetrical push–pull oxotitanium phthalocyanine dyes substituted with tert-butylsulfanyl groups as electron donors and carboxyethynyl units as anchor groups have been designed, prepared, and used with YD2 porphyrin as sensitizer cocktail dyes in dye-sensitized solar cells (DSSCs). The innovative phthalocyanine structures and YD2 and dye cocktails are designed to harvest a broad range from sunlight. The novel phthalocyanine dyes have been characterized via 1H NMR, FTIR, MALDI-TOF, UV–Vis absorption, CV, SWV and TD-DFT techniques. Moreover, the TiO2 NPs has been synthesis by hydrothermal procedure and characterized via XRD, FE-SEM, Raman and DRS techniques. The photoanode has been prepared with synthesized anatase TiO2 NPs using a spin coating procedure. TiO2 photoanode, dye/dye cocktails, I−/I3− electrolyte and Pt/FTO counter electrode have been utilized in the preparation of solar cells. The characterization of the prepared solar cells has been achieved via J-V, Nyquist, Bode, IPCE, normalized JSC and stability measurements. The highest conversion efficiency of the solar cell prepared with YD2:TiOSPPc (3:1) has been performed 10.96%, which this value was found to be higher than the solar cell efficiency of N719 standard dye (8.90%). With these innovative dye cocktails, it is expected that the dye system with not only high efficiency but also a relatively stable and higher VOC value will be an alternative to ruthenium-based dyes.

Advances and perspectives of spin coating techniques

Spin coating is a kind of economically friendly technology accompanied by outstanding application performance, which has been widely adopted in the functional thin film fabrication field. Widespread attention has been attracted owing to their superior controllability. In this paper, the fundamental principles, film quality evaluation methods, and the current development of the spin coating technique are discussed. Through the ideal model and empirical formula, the key factors controlling the film thickness are obtained and are ready to produce marvelous functional films. Currently, the manufacturing demand for solar cells in the energy market is calling for high-quality thin films. Therefore, spin-coating has become a promising candidate. The characteristics of the spin-coating methods reviewed in this paper are adopted to maximize the properties of the obtained films and provide theoretical support for the preparation of high-efficiency solar cells. Finally, this novel growth point of using the spin coating method in the photovoltaic film is forecasted.

Two-step perovskite crystallization assisted with F-containing additives enables over 23% efficiency in perovskite solar cells

The two-step preparation of perovskite solar cells (PSCs) has attracted the interest of many researchers because this method can better control the nucleation and growth of perovskite thin films. This work proposes a crystallization management strategy to improve the quality of active layer with the assistant of F-containing additives with low boiling point. Hexafluorobenzene (HFB) is introduced into lead iodide (PbI2) precursor solutions, and HFB aggregation forms due to its low surface energies. As the result, nano porous PbI2 films are obtained after the evaporation of HFB during annealing process, leading to pinhole free perovskite films with large grain size and low defect states. As the consequence, the best power conversion efficiency (PCE) of 23.01% is obtained for the PSCs with HFB assisted perovskite films. Meanwhile HFB modified unencapsulated device maintains 88% of its initial PCE after aging for over 1440 h at 25 °C and 30% relative humidity in ambient conditions.

Structural parameters and development trend analysis of perovskite solar cells

Calcium titanite solar cells have been one of the hot spots of scientific research in recent years due to their excellent photovoltaic properties. This article talks about calcium titanite solar cells from three aspects: material structure, solar cell internal structure and photovoltaic properties. This paper describes the internal structure of perovskite cell and analyzes its photoelectric conversion principle. At the same time for open circuit voltage, short circuit current, conversion efficiency and other important indicators made a detailed introduction. In view of the current development of solar energy, we hope to make several optimization enhancements, one is to improve the stability of solar panels, the second is to reduce the toxicity of the raw material itself, and the last point is how to prepare the method of large area. It is hoped that the research and improvement in this paper can promote the industrialization and industrial preparation of calcium titanate solar cells, which has positive significance for the development of solar cells.

Preparation and Performance Measurement of Solar Dye Cells

Preparation and Performance Measurement of Solar Dye Cells

Multifunctional interface passivation by benzothiophene amine for stable perovskite solar cells with suppressed charge recombination

Interfacial passivation is the focal point for the preparation of efficient and stable perovskite solar cells. A holistic modification strategy employing multifunctional interfacial material of [1]benzothieno[3,2-b][1]benzothiophene-2-amine (BTBT-NH2) between tin oxide and perovskite is presented in this paper. It can be chemically linked to tin oxide by Lewis base coordination to reduce the oxygen vacancy in tin oxide. Furthermore, BTBT-NH2 containing lone pair electrons can passivate unliganded lead ions in perovskite and anchor lead iodide completely at the bottom of perovskite through N-H bond, forming more nucleation sites and improving the film-forming quality and crystallinity of PbI2 and perovskite. Further analysis reveals that the modification of BTBT-NH2 can reduce trap density, thus suppressing charge recombination and improving power conversion efficiency (PCE). Surprisingly, after being stored at 22 °C and 30% relative humidity in ambient conditions for nearly 1000 h, the unpackaged device maintains 90% of its initial PCE. The results show that BTBT-NH2 interfacial modification is an effective strategy for obtaining stable and efficient perovskite solar cells.

Mechanical properties of multi-scale germanium specimens from space solar cells under electron irradiation

During long-term service in space, Gallium Arsenide (GaAs) solar cells are directly exposed to electron irradiation which usually causes a dramatic decrease in their performance. In the multilayer structure of solar cells, the germanium (Ge) layer occupies the majority of the thickness as the substrate. Due to the intrinsic brittleness of semiconductor material, there exist various defects during the preparation and assembly of solar cells, the influences of which tend to be intensified by the irradiation effect. In this work, first, Ge specimens for mechanical tests were prepared at scales from microscopic to macroscopic. Then, after different doses of electron irradiation, the mechanical properties of the Ge specimens were investigated. The experimental results demonstrate that electron irradiation has an obvious effect on the mechanical property variation of Ge in diverse scales. The four-point bending test indicates that the elastic modulus, fracture strength, and maximum displacement of the Ge specimens all increase, and reach the maximum value at the irradiation dose of 1 × 1015 e/cm2. The micrometer scale cantilever and nanoindentation tests present similar trends for Ge specimens after irradiation. Atomic Force Microscope (AFM) also observed the change in surface roughness. Finally, a fitting model was established to characterize the relation between modulus change and electron irradiation dose.

Effect of the Electron Transport Layer Thickness on I–V Characteristics of the S-Shaped Kinks in Perovskite Solar Cells

In our experimental preparation of perovskite solar cells (PSCs), when the thickness of the electron transport layer (ETL) was changed from thin to thick, the current–voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{I}$</tex-math> </inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{V}$</tex-math> </inline-formula> ) characteristics showed the changing laws of S-shaped kinks appearance, S-shaped kinks disappearance, and S-shaped kinks appearance. A lumped-parameter equivalent circuit model is proposed to reveal the intrinsic physical significances of the S-shaped kinks for this variation laws. The explicit solution of the model is derived using the deformed difference-microvariation (DM) principle combined with the region method, and the model parameters are extracted efficiently through the firefly optimization algorithm (FA). The proposed analytical solution enables the model to be compactly implemented in photovoltaic devices and circuit simulators, and the model is expected to point the direction for process optimization of devices.

Targeted suppression of hysteresis effect in perovskite solar cells through the inhibition of cation migration

The hysteresis effect is a vital issue in perovskite solar cells that warrants close scrutiny, of which ion migration and the resultant interfacial ion accumulation are widely considered to be the most important origination. However, owing to the lack of specific characterization tools to disentangle the complicated interaction between ions and charge carriers, it is yet unidentified which ionic species govern the hysteresis effect, bringing difficulties in further device optimization. Herein, adopting a home-built circuit-switched transient photoelectric technique, whereby ion migration dynamics can be studied without interference from photogenerated charge carriers, the role of different ions in the photoelectric conversion process is elucidated. As suggested by the experimental results, the hysteresis effect dominantly arises from the migration of organic cations instead of the halide anions and can be well interpreted in terms of the strongly coupled cation–electron pairs. On the basis of these findings, we showcase the effectiveness of suppressing the hysteresis factor by the inhibition of the methylamine cations' migration. The present work can provide targeted and sufficient guidance for the preparation of high-stability and high-efficiency perovskite solar cells.

Preparation of Efficient Organic Solar Cells Based on Terpolymer Donors via a Monomer-Ratio Insensitive Side-Chain Hybridization Strategy.

Creating new donor materials is crucial for further advancing organic solar cells. Random terpolymers have been adopted to overcome shortcomings of regular alternating donor-acceptor (D-A) polymers of which the performance is often susceptible to batch-to-batch variations. In general, the properties and performance of efficient D1 -A-D2 -A and D-A1 -D-A2 terpolymers are sensitive to the D1 /D2 or A1 /A2 monomer ratios. Side-chain hybridization is a strategy to address this problem. Here, six D1 -A-D2 -A-type random terpolymers comprising D1 and D2 monomers with the same π-conjugated D unit but with different side chains were synthesized. The side chains, containing either fluorine or trialkylsilyl substituents were chosen to provide near-identical optoelectronic properties but provide a tool to create a better-optimized film morphology when blended with a non-fullerene acceptor. This strategy allows improving the device performance to over 18 %, higher than that obtained with the corresponding D1 -A or D2 -A bipolymers (around 17 %). Hence, side-chain hybridization is a promising strategy to design efficient D1 -A-D2 -A terpolymer donors that are insensitive to the D1 /D2 monomer ratio, which is beneficial for the scaled-up synthesis of high-performance materials.

Enhanced carrier management via optimized SnO2 preparation and film coverage for improved device performance

Optimized electron transport layers (ETLs) can highly promote charge extraction and reduce carrier depopulation. Herein, tin oxide (SnO2) nanocrystals were prepared with the addition of citric acid to suppress SnO2 aggregation and achieve complete film coverage. The dense and uniform SnO2 films with smaller grain sizes will apparently enhance the external quantum efficiency and alleviate the J–V hysteresis behavior. The improved SnO2 film coverage can also passivate traps at ETL/perovskite interfaces and markedly suppress charge recombination to promote rapid carrier injection from perovskite to SnO2. Surely, the optimized SnO2 shows better electrical properties and device performance than Alfa-SnO2. In addition, the diblock-polymer of (PEO)120-(PPO)30 was incorporated into perovskite films to passivate defects and improve device stability. A power conversion efficiency of 23.12% [a VOC of 1.164 V, a JSC of 24.46 mA cm−2, and a fill factor (FF) of 0.812] for the best-performing device is achieved. The charge dynamics (separation, transport, and extraction) were also analyzed using characterization techniques. The optimized device will largely enhance carrier management and light-harvesting performance, and the controlled SnO2 can also open up an effective way to achieve scalable preparation and commercialization of perovskite solar cells.

Preparation of Perovskite Solar Cells in the Air: Degradation Mechanism and Prospects on Large‐Area Fabrication†

Comprehensive SummaryThe preparation of perovskite solar cells (PSCs) in the air environment has attracted the attention of numerous experimenters due to its low preparation cost and the possibility of commercialization. Although the power conversion efficiency (PCE) of PSCs has increased rapidly and exceeded 25%, which is comparable to commercial polysilicon solar cells, most certified or reported high‐efficiency perovskite solar cells are still confined to glove boxes or relatively small active areas in the air environment due to moisture, oxygen, high temperature, and ultraviolet (UV) factors. In this review, the factors that lead to perovskite degradation are reviewed, and the appropriate strategies for manufacturing high‐efficiency and stable perovskite solar cells under environmental conditions are summarized to help the technology be commercialized for high‐quality, stable, and large‐area perovskite thin films in the air.