Hybrid Perovskite‐Organic Flexible Tandem Solar Cell Enabling Highly Efficient Electrocatalysis Overall Water Splitting

Perovskite‐organic tandem solar cells are attracting more attention due to their potential for highly efficient and flexible photovoltaic device. In this work, efficient perovskite‐organic monolithic tandem solar cells integrating the wide bandgap perovskite (1.74 eV) and low bandgap organic active PBDB‐T:SN6IC‐4F (1.30 eV) layer, which serve as the top and bottom subcell, respectively, are developed. The resulting perovskite‐organic tandem solar cells with passivated wide‐bandgap perovskite show a remarkable power conversion efficiency (PCE) of 15.13%, with an open‐circuit voltage (V_oc) of 1.85 V, a short‐circuit photocurrent (J_sc) of 11.52 mA cm^?2, and a fill factor (FF) of 70.98%. Thanks to the advantages of low temperature fabrication processes and the flexibility properties of the device, a flexible tandem solar cell which obtain a PCE of 13.61%, with V_oc of 1.80 V, J_sc of 11.07 mA cm^?2, and FF of 68.31% is fabricated. Moreover, to demonstrate the achieved high V_oc in the tandem solar cells for potential applications, a photovoltaic (PV)‐driven electrolysis system combing the tandem solar cell and water splitting electrocatalysis is assembled. The integrated device demonstrates a solar‐to‐hydrogen efficiency of 12.30% and 11.21% for rigid, and flexible perovskite‐organic tandem solar cell based PV‐driven electrolysis systems, respectively.     

Boosting Photoelectrochemical Water Splitting by TENG‐Charged Li‐Ion Battery

The need for cost‐effective and sustainable power supplies has spurred a growing interest in hybrid energy harvesting systems, and the most elementary energy production process relies on intermittent solar power. Here, it is shown how the ambient mechanical energy leads to water splitting in a photoelectrochemical (PEC) cell boosted by a triboelectric nanogenerator (TENG). In this strategy, a flexible TENG collects and transforms mechanical energy into electric current, which boosts the PEC water splitting via the charged Li‐ion battery. Au nanoparticles are deposited on TiO₂ nanoarrays for extending the available light spectrum to visible part by surface plasmon resonance effect, which yields a photocurrent density of 1.32 mA cm^?2 under AM 1.5 G illumination and 0.12 mA cm^?2 under visible light with a bias of 0.5 V. The TENG‐charged battery boosts the water splitting performance through coupling electrolysis and enhanced electron–hole separation efficiency. The hybrid cell exhibits an instantaneous current more than 9 mA with a working electrode area of 0.3 cm², suggesting a simple but efficient route for simultaneously converting solar radiation and mechanical energy into hydrogen.     

Continuous 3D Titanium Nitride Nanoshell Structure for Solar‐Driven Unbiased Biocatalytic CO2 Reduction

Z‐scheme‐inspired tandem photoelectrochemical (PEC) cells have received attention as a sustainable platform for solar‐driven CO₂ reduction. Here, continuously 3D‐structured, electrically conductive titanium nitride nanoshells (3D TiN) for biocatalytic CO₂‐to‐formate conversion in a bias‐free tandem PEC system are reported. The 3D TiN exhibits a periodically porous network with high porosity (92.1%) and conductivity (6.72 × 10⁴ S m^?1), which allows for high enzyme loading and direct electron transfer (DET) to the immobilized enzyme. It is found that the W‐containing formate dehydrogenase from Clostridium ljungdahlii (ClFDH) on the 3D TiN nanoshell is electrically activated through DET for CO₂ reduction. At a low overpotential of 40 mV, the 3D TiN‐ClFDH stably converts CO₂ to formate at a rate of 0.34 µmol h^?1 cm^?2 and a faradaic efficiency (FE) of 93.5%. Compared to a flat TiN‐ClFDH, the 3D TiN‐ClFDH shows a 58 times higher formate production rate (1.74 µmol h^?1 cm^?2) at 240 mV of overpotential. Lastly, a bias‐free biocatalytic tandem PEC cell that converted CO₂ to formate at an average rate of 0.78 µmol h^?1 and an FE of 77.3% only using solar energy and water is successfully assembled.     

Barium Bismuth Niobate Double Perovskite/Tungsten Oxide Nanosheet Photoanode for High‐Performance Photoelectrochemical Water Splitting

Recently, a new method to effectively engineer the bandgap of barium bismuth niobate (BBNO) double perovskite was reported. However, the planar electrodes based on BBNO thin films show low photocurrent densities for water oxidation owing to their poor electrical conductivity. Here, it is reported that the photoelectrochemical (PEC) activity of BBNO‐based electrodes can be dramatically enhanced by coating thin BBNO layers on tungsten oxide (WO₃) nanosheets to solve the poor conductivity issue while maintaining strong light absorption. The PEC activity of BBNO/WO₃ nanosheet photoanodes can be further enhanced by applying Co_0.8Mn_0.2O_x nanoparticles as a co‐catalyst. A photocurrent density of 6.02 mA cm^?2 at 1.23 V (vs reversible hydrogen electrode (RHE)) is obtained using three optically stacked, but electrically parallel, BBNO/WO₃ nanosheet photoanodes. The BBNO/WO₃ nanosheet photoanodes also exhibit excellent stability in a high‐pH alkaline solution; the photoanodes demonstrate negligible photocurrent density decay while under continuous PEC operation for more than 7 h. This work suggests a viable approach to improve the PEC performance of BBNO absorber‐based devices.     

Diffraction‐Grated Perovskite Induced Highly Efficient Solar Cells through Nanophotonic Light Trapping

Achieving light harvesting is crucial for the efficiency of the solar cell. Constructing optical structures often can benefit from micro‐nanophotonic imprinting. Here, a simple and facile strategy is developed to introduce a large area grating structure into the perovskite‐active layer of a solar cell by utilizing commercial optical discs (CD‐R and DVD‐R) and achieve high photovoltaic performance. The constructed diffraction grating on the perovskite active layer realizes nanophotonic light trapping by diffraction and effectively suppresses carrier recombination. Compared to the pristine perovskite solar cells (PSCs), the diffraction‐grating perovskite devices with DVD obtain higher power conversion efficiency and photocurrent density, which are improved from 16.71% and 21.67 mA cm^?2 to 19.71% and 23.11 mA cm^?2. Moreover, the stability of the PSCs with diffraction‐grating‐structured perovskite active layer is greatly enhanced. The method can boost photonics merge into the remarkable perovskite materials for various applications.     

Infrared Light Management Using a Nanocrystalline Silicon Oxide Interlayer in Monolithic Perovskite/Silicon Heterojunction Tandem Solar Cells with Efficiency above 25%

Perovskite/silicon tandem solar cells are attractive for their potential for boosting cell efficiency beyond the crystalline silicon (Si) single‐junction limit. However, the relatively large optical refractive index of Si, in comparison to that of transparent conducting oxides and perovskite absorber layers, results in significant reflection losses at the internal junction between the cells in monolithic (two‐terminal) devices. Therefore, light management is crucial to improve photocurrent absorption in the Si bottom cell. Here it is shown that the infrared reflection losses in tandem cells processed on a flat silicon substrate can be significantly reduced by using an optical interlayer consisting of nanocrystalline silicon oxide. It is demonstrated that 110 nm thick interlayers with a refractive index of 2.6 (at 800 nm) result in 1.4 mA cm^?² current gain in the silicon bottom cell. Under AM1.5G irradiation, the champion 1 cm² perovskite/silicon monolithic tandem cell exhibits a top cell + bottom cell total current density of 38.7 mA cm^?2 and a certified stabilized power conversion efficiency of 25.2%.     

Improved Optics in Monolithic Perovskite/Silicon Tandem Solar Cells with a Nanocrystalline Silicon Recombination Junction

Perovskite/silicon tandem solar cells are increasingly recognized as promi­sing candidates for next‐generation photovoltaics with performance beyond the single‐junction limit at potentially low production costs. Current designs for monolithic tandems rely on transparent conductive oxides as an intermediate recombination layer, which lead to optical losses and reduced shunt resistance. An improved recombination junction based on nanocrystalline silicon layers to mitigate these losses is demonstrated. When employed in monolithic perovskite/silicon heterojunction tandem cells with a planar front side, this junction is found to increase the bottom cell photocurrent by more than 1 mA cm^?2. In combination with a cesium‐based perovskite top cell, this leads to tandem cell power‐conversion efficiencies of up to 22.7% obtained from J–V measurements and steady‐state efficiencies of up to 22.0% during maximum power point tracking. Thanks to its low lateral conductivity, the nanocrystalline silicon recombination junction enables upscaling of monolithic perovskite/silicon heterojunction tandem cells, resulting in a 12.96 cm² monolithic tandem cell with a steady‐state efficiency of 18%.     

Inverted Tandem Polymer Solar Cells with Polyethylenimine‐Modified MoOX/Al2O3:ZnO Nanolaminate as the Charge Recombination Layers

A new charge recombination layer for inverted tandem polymer solar cells is reported. A bilayer of MoO_X/Al₂O₃:ZnO nanolaminate is shown to enable efficient charge recombination in inverted tandem cells. A polymer surface modification on the MoO_X/Al₂O₃:ZnO nanolaminate bilayer increases the work function contrast between the two outward surfaces of the charge recombination layer, further improving the performance of tandem solar cells. An analysis of the electrical, optical, and surface properties of the charge recombination layer is presented. Inverted tandem polymer solar cells, with two photoactive layers comprising poly (3‐hexylthiophene) (P3HT):indene‐C₆₀ bisadduct (IC₆₀BA) for the bottom cell and poly[(4,8‐bis‐(2‐ethylhexyloxy)‐benzo[1,2‐b:4,5‐b']dithiophene)‐2,6‐diyl‐alt‐(4‐(2‐ethylhexanoyl)‐thieno[3,4‐b]thiophene))‐2,6‐diyl] (PBDTTT‐C):[6,6]‐phenyl C₆₁ butyric acid methyl ester (PC₆₀BM) for the top cell, yield an open‐circuit voltage of 1481 mV ± 15 mV, a short‐circuit current density of 7.1 mA cm^?2 ± 0.1 mA cm^?2, and a fill factor of 0.62 ± 0.01, resulting in a power conversion efficiency of 6.5% ± 0.1% under simulated AM 1.5G, 100 mW cm^?2 illumination.     

Fullerene as a Photoelectron Transfer Promoter Enabling Stable TiO2‐Protected Sb2Se3 Photocathodes for Photo‐Electrochemical Water Splitting

Understanding the degradation mechanisms of photoelectrodes and improving their stability are essential for fully realizing solar‐to‐hydrogen conversion via photo‐electrochemical (PEC) devices. Although amorphous TiO₂ layers have been widely employed as a protective layer on top of p‐type semiconductors to implement durable photocathodes, gradual photocurrent degradation is still unavoidable. This study elucidates the photocurrent degradation mechanisms of TiO₂‐protected Sb₂Se₃ photocathodes and proposes a novel interface‐modification methodology in which fullerene (C₆₀) is introduced as a photoelectron transfer promoter for significantly enhancing long‐term stability. It is demonstrated that the accumulation of photogenerated electrons at the surface of the TiO₂ layer induces the reductive dissolution of TiO₂, accompanied by photocurrent degradation. In addition, the insertion of the C₆₀ photoelectron transfer promoter at the Pt/TiO₂ interface facilitates the rapid transfer of photogenerated electrons out of the TiO₂ layer, thereby yielding enhanced stability. The Pt/C₆₀/TiO₂/Sb₂Se₃ device exhibits a high photocurrent density of 17 mA cm^?2 and outstanding stability over 10 h of operation, representing the best PEC performance and long‐term stability compared with previously reported Sb₂Se₃‐based photocathodes. This research not only provides in‐depth understanding of the degradation mechanisms of TiO₂‐protected photocathodes, but also suggests a new direction to achieve durable photocathodes for photo‐electrochemical water splitting.     

Overcoming Charge Collection Limitation at Solid/Liquid Interface by a Controllable Crystal Deficient Overlayer

Bulk and surface charge recombination of photoelectrode are two key processes that significantly hinder solar‐to‐fuel conversion of photoelectrochemical cell (PEC). In this study, the function of a “crystal‐deficient” overlayer is unveiled, which outperforms a traditionally used amorphous or crystalline overlayer in PEC water splitting by exhibiting a high conductivity and large electron diffusion length to enable unlimited electron collection. The optimized ≈2.5 nm thickness of the “crystal‐deficient” shell results in a depletion layer with a width of 3 nm, which overcomes the flat band limitation of the photovoltage and increases the light absorptivity in the wavelength range from 300 to 420 nm. In addition, a 50‐fold increase in the conductivity yields a one‐order‐of‐magnitude increase in the diffusion length of an electron (L_n )(≈20 μm), allowing for unlimited electron collection in the 1.9 μm TiO₂ nanowire array with the “crystal‐deficient” shell. The controllable “crystal‐deficient” overlayer in rutile TiO₂ nanowires photoanode achieves a photocurrent density greater than 2.0 mA cm^?2 at 1.23 V versus reversible hydrogen electrode (RHE), a 1.18% applied bias photon‐to‐current efficiency at 0.49 V versus RHE, a faradaic efficiency greater than 93.5% at 0.6 V versus Pt under air mass 1.5G simulated solar light illumination (100 mW cm^?2).     

A Sandwich‐Like Organolead Halide Perovskite Photocathode for Efficient and Durable Photoelectrochemical Hydrogen Evolution in Water

Organolead halide perovskite materials have demonstrated great potential in the solar cells field owing to their excellent optoelectronic properties. However, the instability issue of the perovskites impedes the translation of their attractive features for the solar fuel production such as photoelectrochemical H₂ production from water splitting. Herein, CH₃NH₃PbI₃ a photocathode with a sandwich‐like structure is fabricated with a general and scalable approach toward addressing this issue. The photocathode exhibits an onset potential at 0.95 V versus reversible hydrogen electrode (RHE) and a photocurrent density of ?18 mA cm^?2 at 0 V versus RHE with an impressive ideal ratiometric power‐saved efficiency of 7.63%. More impressively, the photocathode retains good stability under 12 h continuous illumination in water at wide pH range. This performance is much superior to that of the best perovskite‐based photoelectrode ever reported.     

Diammonium and Monoammonium Mixed‐Organic‐Cation Perovskites for High Performance Solar Cells with Improved Stability

Remarkable power conversion efficiencies (PCE) of metal–halide perovskite solar cells (PSCs) are overshadowed by concerns about their ultimate stability, which is arguably the prime obstacle to commercialization of this promising technology. Herein, the problem is addressed by introducing ethane‐1,2‐diammonium (⁺NH₃(CH₂)₂NH₃⁺, EDA²⁺) cations into the methyl ammonium (CH₃NH₃⁺, MA⁺) lead iodide perovskite, which enables, inter alia, systematic tuning of the morphology, electronic structure, light absorption, and photoluminescence properties of the perovskite films. Incorporation of <5 mol% EDA²⁺ induces strain in the perovskite crystal structure with no new phase formed. With 0.8 mol% EDA²⁺, PCE of the MAPbI₃‐based PSCs (aperture of 0.16 cm²) improves from 16.7% ± 0.6% to 17.9% ± 0.4% under 1 sun irradiation, and fabrication of larger area devices (aperture 1.04 cm²) with a certified PCE of 15.2% ± 0.5% is demonstrated. Most importantly, EDA²⁺/MA⁺‐based solar cells retain 75% of the initial performance after 72 h of continuous operation at 50% relative humidity and 50 °C under 1 sun illumination, whereas the MAPbI₃ devices degrade by approximately 90% within only 15 h. This substantial improvement in stability is attributed to the steric and coulombic interactions of embedded EDA²⁺ in the perovskite structure.     

Targeting Ideal Dual‐Absorber Tandem Water Splitting Using Perovskite Photovoltaics and CuInxGa1‐xSe2 Photocathodes

Efficient sunlight‐driven water splitting devices can be achieved by pairing two absorbers of different optimized bandgaps in an optical tandem design. With tunable absorption ranges and cell voltages, organic–inorganic metal halide perovskite solar cells provide new opportunities for tailoring top absorbers for such devices. In this work, semitransparent perovskite solar cells are developed for use as the top cell in tandem with a smaller bandgap photocathode to enable panchromatic harvesting of the solar spectrum. A new CuIn_xGa_1‐xSe₂ multilayer photocathode is designed, exhibiting excellent performance for photoelectrochemical water reduction and representing a near‐ideal bottom absorber. When pairing it below a semitransparent CH₃NH₃PbBr₃‐based solar cell, a solar‐to‐hydrogen efficiency exceeding 6% is achieved, the highest value yet reported for a photovoltaic–photoelectrochemical device utilizing a single‐junction solar cell as the bias source under one sun illumination. The analysis shows that the efficiency can reach more than 20% through further optimization of the perovskite top absorber.     

Light‐Driven BiVO4–C Fuel Cell with Simultaneous Production of H2O2

Photoelectrochemical (PEC) systems have been researched for decades due to their great promise to convert sunlight to fuels. The majority of the research on PEC has been using light to split water to hydrogen and oxygen, and its performance is limited by the need of additional bias. Another research direction on PEC using light, is to decompose organic materials while producing electricity. In this work, the authors report a new type of unassisted PEC system that uses light, water and oxygen to simultaneously produce electricity and hydrogen peroxide (H₂O₂) on both the photoanode and cathode, which is essentially a light‐driven fuel cell with H₂O₂ as the main product at the two electrodes, meanwhile achieving a maximum power density of 0.194 mW cm^‐2, an open circuit voltage of 0.61 V, and a short circuit current density of 1.09 mA cm^‐2. The electricity output can be further used as a sign for cell function when accompanied by a detector such as a light‐emitting diode (LED) light or a multimeter. This is the first work that shows H₂O₂ two‐side generation with a strict key factors study of the system, with a clear demonstration of electricity output ability using low‐cost earth abundant materials on both sides, which represents an exciting new direction for PEC systems.     

Over 17% Efficiency Stand‐Alone Solar Water Splitting Enabled by Perovskite‐Silicon Tandem Absorbers

Realizing solar‐to‐hydrogen (STH) efficiencies close to 20% using low‐cost semiconductors remains a major step toward accomplishing the practical viability of photoelectrochemical (PEC) hydrogen generation technologies. Dual‐absorber tandem cells combining inexpensive semiconductors are a promising strategy to achieve high STH efficiencies at a reasonable cost. Here, a perovskite photovoltaic biased silicon (Si) photoelectrode is demonstrated for highly efficient stand‐alone solar water splitting. A p⁺nn⁺ ‐Si/Ti/Pt photocathode is shown to present a remarkable photon‐to‐current efficiency of 14.1% under biased condition and stability over three days under continuous illumination. Upon pairing with a semitransparent mixed perovskite solar cell of an appropriate bandgap with state‐of‐the‐art performance, an unprecedented 17.6% STH efficiency is achieved for self‐driven solar water splitting. Modeling and analysis of the dual‐absorber PEC system reveal that further work into replacing the noble‐metal catalyst materials with earth‐abundant elements and improvement of perovskite fill factor will pave the way for the realization of a low‐cost high‐efficiency PEC system.     

Surface State‐Mediated Charge Transfer of Cs2SnI6 and Its Application in Dye‐Sensitized Solar Cells

A vacancy‐ordered double perovskite, Cs₂SnI₆, has emerged as a promising lead‐free perovskite in the optoelectronic field. However, the charge transfer kinetics mediated by its surface state remains unclear. Here, the charge transfer mechanism of Cs₂SnI₆ is reported and the role of its surface state in the presence of a redox mediator is clarified. Specifically, charge transfer through the surface state of Cs₂SnI₆ and its subsequent surface state charging are demonstrated by cyclic voltammetry and Mott–Schottky measurements, respectively. Because it is expected that the surface state of Cs₂SnI₆ is capable of regenerating oxidized organic dyes, a Cs₂SnI₆‐based regenerator is developed for a dye‐sensitized solar cell composed of fluorine‐doped tin oxide (FTO)/dyed mesoporous TiO₂/regenerator/poly(3,4‐ethylenedioxythiophene)/FTO. As expected, the performance of the Cs₂SnI₆‐based regenerator is strongly dependent on the highest occupied molecular orbital of the dyes. Consequently, Cs₂SnI₆ shows efficient charge transfer with a thermodynamically favorable charge acceptor level, achieving a 79% enhancement in the photocurrent density (14.1 mA cm^?2) compared with that of a conventional liquid electrolyte (7.9 mA cm^?2). The results suggest that the surface state of Cs₂SnI₆ is the main charge transfer pathway in the presence of a redox mediator and should be considered in future designs of Cs₂SnI₆‐based devices.     

A Cu‐Based Nanoparticulate Film as Super‐Active and Robust Catalyst Surpasses Pt for Electrochemical H2 Production from Neutral and Weak Acidic Aqueous Solutions

Electrocatalysts that are stable and highly active at low overpotential (η) under mild conditions as well as cost‐effective and scalable are eagerly desired for potential use in photo‐ and electro‐driven hydrogen evolution devices. Here the fabrication and characterization of a super‐active and robust Cu‐Cu_xO‐Pt nanoparticulate electrocatalyst is reported, which displays a small Tafel slope (44 mV dec^?1) and a large exchange current density (1.601 mA cm^?2) in neutral buffer solution. The catalytic current density of this catalyst film reaches 500 mA cm^?2 at η = ?390 ± 12 mV and 20 mA cm^?2 at η = ?45 ± 3 mV, which are significantly higher than the values displayed by Pt foil and Pt/C electrodes in neutral buffer solution and even comparable with the activity of Pt electrode in 0.5 m H₂SO₄ solution.     

Constructing a AZO/TiO2 Core/Shell Nanocone Array with Uniformly Dispersed Au NPs for Enhancing Photoelectrochemical Water Splitting

Constructing core/shell nanostructures with optimal structure and composition could maximize the solar light utilization. Here, using an Al nanocone array as a substrate, a well‐defined regular array of AZO/TiO₂ core/shell nanocones with uniformly dispersed Au nanoparticles (AZO/TiO₂/Au NCA) is successfully realized through three sequential steps of atomic layer deposition, physical vapor deposition, and annealing processes. By tuning the structural and compositional parameters, the advantages of light trapping and short carrier diffusion from the core/shell nanocone array, as well as the surface plasmon resonance and catalytic effects from the Au nanoparticles can be maximally utilized. Accordingly, a remarkable photoelectrochemical (PEC) performance can be acquired and the photocurrent density of the AZO/TiO₂/Au NCA electrode reaches up to 1.1 mA cm^?2 at 1.23 V, versus reversible hydrogen electrode (RHE) under simulated sunlight illumination, which is five times that of a flat AZO/TiO₂ electrode (0.22 mA cm^?2). Moreover, the photoconversion of the AZO/TiO₂/Au NCA electrode approaches 0.73% at 0.21 V versus RHE, which is one of the highest values with the lowest applied bias ever reported in Au/TiO₂ PEC composites. These results demonstrate a feasible route toward the scalable fabrication of well‐modulated core/shell nanostructures and can be easily applied to other metal/semiconductor composites for high‐performance PEC.     

Efficient Solar‐Driven Water Oxidation over Perovskite‐Type BaNbO2N Photoanodes Absorbing Visible Light up to 740 nm

Photoelectrochemical water splitting using semiconductors absorbing a wide range of visible light is a potentially attractive means of harvesting large portions of the solar spectrum. However, this is also very challenging because narrowing the semiconductor band gap lowers the driving force for photoreactions. Herein, a highly active perovskite BaNbO₂N exhibiting photoexcitation up to 740 nm for water oxidation is reported. The synthesis route, consisting of moderate nitridation and subsequent annealing in inert Ar flow, enhances the crystallinity of the BaNbO₂N surface without inducing the reduction of the Nb species. As a result, a particulate BaNbO₂N photoanode exhibits a photocurrent of 5.2 mA cm^?2 at 1.23 V_RHE under simulated solar irradiation, which is the highest yet reported for an oxynitride responsive at wavelengths above 600 nm. Suppressing the reduction of B‐site cations during the synthesis of perovskite AB(O,N)₃, which otherwise results in surface defects or impurities, is critical for achieving high water oxidation activity.     

Vacuum‐Assisted Growth of Low‐Bandgap Thin Films (FA0.8MA0.2Sn0.5Pb0.5I3) for All‐Perovskite Tandem Solar Cells

All‐perovskite multijunction photovoltaics, combining a wide‐bandgap (WBG) perovskite top solar cell (E_G ≈1.6–1.8 eV) with a low‐bandgap (LBG) perovskite bottom solar cell (E_G < 1.3 eV), promise power conversion efficiencies (PCEs) >33%. While the research on WBG perovskite solar cells has advanced rapidly over the past decade, LBG perovskite solar cells lack PCE as well as stability. In this work, vacuum‐assisted growth control (VAGC) of solution‐processed LBG perovskite thin films based on mixed Sn–Pb perovskite compositions is reported. The reported perovskite thin films processed by VAGC exhibit large columnar crystals. Compared to the well‐established processing of LBG perovskites via antisolvent deposition, the VAGC approach results in a significantly enhanced charge‐carrier lifetime. The improved optoelectronic characteristics enable high‐performance LBG perovskite solar cells (1.27 eV) with PCEs up to 18.2% as well as very efficient four‐terminal all‐perovskite tandem solar cells with PCEs up to 23%. Moreover, VAGC leads to promising reproducibility and potential in the fabrication of larger active‐area solar cells up to 1 cm².