Lead Perovskite Solar Cells Research Articles

All-Perovskite Tandem Solar Cells Approach 26.5% Efficiency by Employing Wide Bandgap Lead Perovskite Solar Cells with New Monomolecular Hole Transport Layer

All-Perovskite Tandem Solar Cells Approach 26.5% Efficiency by Employing Wide Bandgap Lead Perovskite Solar Cells with New Monomolecular Hole Transport Layer

Efficiency Enhancement of Wide Bandgap Lead Perovskite Solar Cells with PTAA Surface-Passivated with Monomolecular Layer from the Viewpoint of PTAA Band Bending.

This report is on the efficiency enhancement of wide bandgap lead halide perovskite solar cells (WBG Pb-PVK PSCs) consisting of FA0.8Cs0.2PbI1.8Br1.2 as the light-harvesting layer. WGB Pb-PVK PSCs have attracted attention as the top layer of all perovskite-tandem solar cells. Poly[bis(4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA), a conductive polymer, is always used as the hole transporting layer (HTL) for Pb-PVK PSCs. Nevertheless, the hydrophobic surface of the PTAA sometimes destroys the growth of the FA0.8Cs0.2PbI1.8Br1.2 film. On the other hand, the Fermi level of PTAA is not well matched with that of perovskite film. Thus, the PCE of the WBG Pb-based PSCs with PTAA as the HTL was not very high. In this report, the efficiency of the FA0.8Cs0.2PbI1.8Br1.2 is improved by passivating the surface of the PTAA with a monomolecular layer, where the surface becomes hydrophilic, and the band bending of the PTAA layer is improved to cause swift hole collection. Finally, WBG Pb-PVK PSCs (1.77 eV) with 16.52% efficiency are reported.

Urea additive improves the performance of low bandgap tin–lead perovskite solar cells

Recently, narrow bandgap tin–lead mixed perovskite solar cells (PSCs) have become a research hotspot because they can be applied in tandem cells to break the Shockley–Queisser radiative limit of the single junction PSCs. However, the introduction of tin, on the one hand, makes the crystal quality of perovskite thin film worse, leading to the increase of film defects; on the other hand, the easy oxidation of divalent tin also leads to the increase of defect states, which seriously affects the photoelectric conversion efficiency of tin–lead cell devices. Good crystallization and low defect density of perovskite layer are very important to ensure good light absorption and photogenerated carrier generation and transport. Here, we adjust the crystallization of tin–lead perovskite films by a Lewis base—urea (CO(NH2)2), which significantly increases the grain size and improves the film morphology. At the same time, because of the Lewis base property of urea, the uncoordinated Pb2+ and Sn2+ defects of Lewis acids in the tin–lead films are effectively passivated, and the occurrence of non-radiative recombination in the films is reduced. Under the dual effects of improving crystallization and passivating defects, the photoelectric performance of tin–lead perovskite solar cell devices is significantly improved to 18.1% compared with the original device of 15.4%.

High Performance 2D/3D Tin–Lead Perovskite Solar Cells Achieved by Phenethylamine Acetate Post-Treatment

High Performance 2D/3D Tin–Lead Perovskite Solar Cells Achieved by Phenethylamine Acetate Post-Treatment

Improved Carrier Management via a Multifunctional Modifier for High-Quality Low-Bandgap Sn-Pb Perovskites and Efficient All-Perovskite Tandem Solar Cells.

All-perovskite tandem solar cells (TSCs) hold great promise in terms of ultrahigh efficiency, low manufacturing cost, and flexibility, stepping forward to the next-generation photovoltaics. However, their further development is hampered by the relatively low performance of low-bandgap (LBG) tin (Sn)-lead (Pb) perovskite solar cells (PSCs). Improving the carrier management, including suppressing trap-assisted non-radiative recombination and promoting carrier transfer, is of great significance to enhance the performance of Sn-Pb PSCs. Herein, a carrier management strategy is reported for using cysteine hydrochloride (CysHCl) simultaneously as a bulky passivator and a surface anchoring agent for Sn-Pb perovskite. CysHCl processing effectively reduces trap density and suppresses non-radiative recombination, enabling the growth of high-quality Sn-Pb perovskite with greatly improved carrier diffusion length of >8µm. Furthermore, the electron transfer at the perovskite/C60 interface is accelerated due to the formation of surface dipoles and favorable energy band bending. As a result, these advances enable the demonstration of champion efficiency of 22.15% for CysHCl-processed LBG Sn-Pb PSCs with remarkable enhancement in both open-circuit voltage and fill factor. When paired with a wide-bandgap (WBG) perovskite subcell, a certified 25.7%-efficient all-perovskite monolithic tandem device is further demonstrated.

Implications of Electron Transport Layer and Back Metal Contact Variations in Tin–Lead Perovskite Solar Cells Assessed by Spectroscopic Ellipsometry and External Quantum Efficiency

The structural and optical properties of hybrid organic-inorganic metal halide perovskite solar cells are measured by spectroscopic ellipsometry to reveal an optically distinct interfacial layer among the back contact metal, charge transport, and absorber layers. Understanding how this interfacial layer impacts performance is essential for developing higher performing solar cells. This interfacial layer is modeled by Bruggeman effective medium approximations (EMAs) to contain perovskite, C60, BCP, and metal. External quantum efficiency (EQE) simulations that consider scattering, electronic losses, and the formation of nonparallel interfaces are created with input derived from ellipsometry structural-optical models and compared with experimental EQE to estimate optical losses. This nonplanar interface causes optical losses in short circuit current density (JSC) of up to 1.2 mA cm-2. A study of glass/C60/SnO2/Ag or Cu and glass/C60/BCP/Ag film stacks shows that C60 and BCP mix, but replacing BCP with SnO2 can prevent mixing between the ETLs to prevent contact between C60 and back contact metal and enable the formation of a planar interface between ETLs and back contact metals.

Bifunctional additive 2-amino-3-hydroxypyridine for stable and high-efficiency tin–lead perovskite solar cells

A schematic illustration of the interaction between perovskites and AHPD, and the effect of AHPD on the microstructure evolution of the films.

Germanium–lead double absorber layer perovskite solar cells: Further performance enhancement from the perspective of device simulation

Germanium–lead double absorber layer perovskite solar cells: Further performance enhancement from the perspective of device simulation

Factors Limiting the Operational Stability of Tin–Lead Perovskite Solar Cells

Factors Limiting the Operational Stability of Tin–Lead Perovskite Solar Cells

A MINI-REVIEW OF RECENT STUDIES ON LEAD AND LEAD-FREE PEROVSKITE MATERIALS FOR SOLAR CELLS APPLICATION AND THEIR ISSUES

Perovskite is gaining popularity in solar cell technologies and optoelectronics that rely on lead-based material. Perovskite solar cell (PSC) technologies are viewed as promising forthcoming innovations for their proficiency and monetary of the thin film due to high demand in the technology market. Lead-free perovskite material has become a viable alternative to lead-based perovskite, which has dominated the solar cell market for many years, due to toxicity and stability difficulties that have plagued lead-based solar cells. The large-scale commercial manufacture of lead-free halide perovskites solar cells can be expanded and its benefits in the solar field could be enhanced. Compared with lead-based perovskite, the lead-free perovskite material could also achieve a high-power conversion efficiency (PCE) indicating good solar cell performance. This review studied the perovskite materials, challenge of lead perovskite solar cell commercialization and summarizes recent research work regarding the perovskite solar cell. Moreover, this review forecast the future of perovskite solar cells in parallel with the Third Generation of Solar Cells.

Carbazole-Based Hole Transport Polymer for Methylammonium-Free Tin–Lead Perovskite Solar Cells with Enhanced Efficiency and Stability

As the most commonly used hole transport material (HTM) in tin–lead (Sn–Pb) perovskite solar cells (PSCs), poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) limits the power conversion efficiency (PCE) and stability of the PSCs due to its acidic characteristics. Herein, an easily synthesized polymer HTM poly[(phenyl)imino[9-(2-ethylhexyl)carbazole]-2,7-diyl] (CzAn) with a shallow highest occupied molecular orbital (HOMO) level of −4.95 eV is used in a p-i-n structure, methylammonium-free, Sn–Pb PSC to replace PEDOT:PSS. Upon optimization using doping and surface engineering, high quality Sn–Pb PSCs could be successfully fabricated, boosting the PCE to 22.6% (stabilized PCE of 21.3%) compared with 21.2% for PEDOT:PSS. The perovskite films prepared on the modified CzAn HTM possess improved crystallinity, reduced trap-state density, and larger carrier mobility resulting in PSCs with greatly improved stability.

Carbonyl functional group assisted crystallization of mixed tin–lead narrow bandgap perovskite absorber in ambient conditions

Tin–lead (Sn–Pb) perovskite solar cells are receiving growing interest due to their applications in tandems and lead mitigation. Nonetheless, fast crystallization and facile Sn2+ oxidation restrict their ambient fabrication, which increases fabrication costs. This Letter presents an experimental study on additive assisted growth of FA0.2MA0.8Sn0.5Pb0.5I2.4Br0.6 narrow bandgap perovskite films employing a Lewis-base molecule, caffeine (1,3,7-trimethylpurine-2,6-dione), having two carbonyl functional groups (C = O) in ambient conditions (relative humidity < ∼10%). The C = O interacts with metallic ions (Sn2+ and Pb2+) via chelation to form an acid–base adduct, slowing down the fast crystallization of FA0.2MA0.8Sn0.5Pb0.5I2.4Br0.6 perovskite films. As a result, the grain size improves resulting in better structural and optical properties. In contrast, Urbach energy values showed higher electronic disorder near the band edges even upon caffeine doping implying Sn4+ doping in an ambient environment. This work accentuates the potential of the acid–base adduction to regulate uncontrolled crystallization of Sn–Pb perovskites in the ambient environment.

Low-Bandgap Mixed Tin–Lead Perovskite Solar Cells

Low-bandgap mixed tin (Sn)–lead (Pb) perovskite solar cells have been extensively investigated in the past few years due to their great potential in high-performance perovskite/perovskite tandem solar cells. From this perspective, we briefly summarize the mechanism of understanding of additives and the advances in the efficiency and stability of such low-bandgap Sn-Pb perovskite materials and solar cells in terms of various effective strategies for suppressing the defects and oxidation of Sn2+, regulating crystallization growth, etc. We then provide a perspective regarding the achievement of high-quality, low-bandgap Sn-Pb perovskites and highly efficient solar cells.

Enhanced efficiency and stability in Sn-based perovskite solar cells by trimethylsilyl halide surface passivation

Enhanced efficiency and stability in Sn-based perovskite solar cells by trimethylsilyl halide surface passivation

Tin–Lead Perovskite Solar Cells Fabricated on Hole Selective Monolayers

Tin–Lead Perovskite Solar Cells Fabricated on Hole Selective Monolayers

Optimized carrier extraction at interfaces for 23.6% efficient tin–lead perovskite solar cells

This work provides an efficient way to facilitate both electron and hole extraction in the designated interfaces of perovskite solar cells. A record power conversion efficiency of 23.6% for mixed Sn–Pb perovskite solar cell devices is realized.

The role of A-site composition in the photostability of tin–lead perovskite solar cells

The content of methylammonium dominates the photostability of tin–lead perovskite solar cells.

In Situ Stabilized CsPbI3 for Air‐Fabricated Inverted Inorganic Perovskite Photovoltaics with Wide Humidity Operating Window

AbstractInverted triiodine cesium lead (CsPbI3) perovskite solar cells (PSCs) are promising in photovoltaics owing to their ideal light absorption, non‐volatile active layer, and avoidance of fragile Spiro‐OmeTAD, especially as the top cell in tandem devices. However, they still exhibit far‐lagging efficiency, and must be processed in a strictly controlled environment due to water‐fearing CsPbI3. Here, a novel strategy to convert the harmful water erosions into an in situ stabilizer for efficient inverted CsPbI3 PSCs fabricated with a wide humidity operating window, is proposed. During air fabrication, maleic anhydride (MAAD) can react with water molecules in air to reduce moisture erosions, while the hydrolysis products (maleic acid, MAAC) control grains growth. After annealing, MAAC strongly binds to CsPbI3 grains as a shield to hamper phase transition and moisture penetration. A champion efficiency of 19.25% is obtained, which is the highest efficiency among the inverted inorganic PSCs. In parallel, the authors’ optimized devices present efficiency of 18.39% even fabricated in relative humidity 60% condition. Moreover, the stability against various ages is improved, and the optimized devices remain at 96.8% of its initial efficiency after maximum power point tracking at 65 °C for 850 h.

Unveiling Roles of Tin Fluoride Additives in High‐Efficiency Low‐Bandgap Mixed Tin‐Lead Perovskite Solar Cells

AbstractLow‐bandgap mixed tin–lead perovskite solar cells (PSCs) have been attracting increasing interest due to their appropriate bandgaps and promising application to build efficient all‐perovskite tandem cells, an effective way to break the Shockley–Queisser limit of single‐junction cells. Tin fluoride (SnF2) has been widely used as a basis along with various strategies to improve the optoelectronic properties of low‐bandgap SnPb perovskites and efficient cells. However, fully understanding the roles of SnF2 in both films and devices is still lacking and fundamentally desired. Here, the functions of SnF2 in both low‐bandgap (FASnI3)0.6(MAPbI3)0.4 perovskite films and efficient devices are unveiled. SnF2 regulates the growth mode of low‐bandgap SnPb perovskite films, leading to highly oriented topological growth and improved crystallinity. Meanwhile, SnF2 prevents the oxidation of Sn2+ to Sn4+ and reduces Sn vacancies, leading to reduced background hole density and defects, and improved carrier lifetime, thus largely decreasing nonradiative recombination. Additionally, the F− ion preferentially accumulates at hole transport layer/perovskite interface with high SnF2 content, leading to more defects. This work provides in‐depth insights into the roles of SnF2 additives in low‐bandgap SnPb films and devices, assisting in further investigations into multiple additives and approaches to obtain efficient low‐bandgap PSCs.

Improving Photovoltaic Performance of Pb‐Less Halide Perovskite Solar Cells by Incorporating Bulky Phenylethylammonium Cations

Alloyed tin–lead (Sn–Pb) perovskite solar cells (PSCs) exhibit a broader photoresponse up to 1050 nm; however, their efficiency is inferior to that of Pb analogs. Trap‐assisted recombination associated with Sn vacancies formed through Sn2+ oxidation is a major detrimental factor, limiting their efficiency. By incorporating bulkier phenylethylammonium (PEA) cations into Sn–Pb alloyed perovskites, the nonradiative recombination by lowering the number of defects associated with Sn vacancies is reduced. Herein, the effects of PEA cations in different Sn–Pb halide perovskite compositions with a series of characterizations, such as photoluminescence, X‐ray photoelectron spectroscopy, and surface potential measurements, are investigated. As a result of the reduction of traps in PEA‐containing perovskites, a significant improvement of 40% and 15% in photovoltaic performance is observed for Sn‐rich and Pb‐rich Sn–Pb halide perovskites, respectively.