Synergistic Crystal and Interface Engineering for Efficient and Stable Perovskite Photovoltaics

The presence of bulk and surface defects in perovskite light harvesting materials limits the overall efficiency of perovskite solar cells (PSCs). The formation of such defects is suppressed by adding methylammonium chloride (MACl) as a crystallization aid to the precursor solution to realize high‐quality, large‐grain triple A‐cation perovskite films and that are combined with judicious engineering of the perovskite interface with the electron and hole selective contact materials. A planar SnO₂/TiO₂ double layer oxide is introduced to ascertain fast electron extraction and the surface of the perovskite facing the hole conductor is treated with iodine dissolved in isopropanol to passivate surface trap states resulting in a retardation of radiationless carrier recombination. A maximum solar to electric power conversion efficiency (PCE) of 21.65% and open circuit photovoltage (V_oc) of ≈1.24 V with only ≈370 mV loss in potential with respect to the band gap are achieved, by applying these modifications. Additionally, the defect healing enhances the operational stability of the devices that retain 96%, 90%, and 85% of their initial PCE values after 500 h under continuously light illumination at 20, 50, and 65 °C, respectively, demonstrating one of the most stable planar PSCs reported so far.     

Exploring the Stability of Novel Wide Bandgap Perovskites by a Robot Based High Throughput Approach

Currently, lead‐based perovskites with mixed multiple cations and hybrid halides are attracting intense research interests due to their promising stability and high efficiency. A tremendous amount of 3D and 2D perovskite compositions and configurations are causing a strong demand for high throughput synthesis and characterization. Furthermore, wide bandgap (≈1.75 eV) perovskites as promising top‐cell materials for perovskite–silicon tandem configurations require the screening of different compositions to overcome photoinduced halide segregation and still yielding a high open‐circuit voltage (V_oc). Herein, a home‐made high throughput robot setup is introduced performing automatic perovskite synthesis and characterization. Subsequently, four kinds of compositions (i.e., cation mixtures of Cs–methylammonium (MA), Cs– formamidinium (FA), MA–FA, and FA–MA) with an optical bandgap of ≈1.75 eV are identified as promising device candidates. For Cs–MA and Cs–FA films it is found that the Br–I phase segregation indeed can be overcome. Moreover, Cs–MA, MA–FA, and Cs–FA based devices exhibit an average V_oc of 1.17, 1.17, 1.12 V, and their maximum values approached 1.18, 1.19, 1.14 V, respectively, which are among the highest V_oc (≈1.2 V) values for ≈40% Br perovskite. These findings highlight that the high throughput approach can effectively and efficiently accelerate the invention of novel perovskites for advanced applications.     

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.     

Efficient Organic Solar Cells with Extremely High Open‐Circuit Voltages and Low Voltage Losses by Suppressing Nonradiative Recombination Losses

One of the most important factors that limits the efficiencies of bulk‐heterojunction organic solar cells (OSCs) is the modest open‐circuit voltage (V_oc) due to their large voltage loss (V_loss) caused by significant nonradiative recombination loss. To boost the performance of OSCs toward their theoretical limit, developing high‐performance donor: acceptor systems featuring low V_loss with suppressed nonradiative recombination losses (<0.30 V) is desired. Herein, high performance OSCs based on a polymer donor benzodithiophene‐difluorobenzoxadiazole‐2‐decyltetradecyl (BDT‐ffBX‐DT) and perylenediimide‐based acceptors (PDI dimer with spirofluorene linker (SFPDI), PDI4, and PDI6) are reported which offer a high power conversion efficiency (PCE) of 7.5%, 56% external quantum efficiency associated with very high V_oc (>1.10 V) and low V_loss (<0.60 V). A high V_oc up to 1.23 V is achieved, which is among the highest values reported for OSCs with a PCE beyond 6%, to date. These attractive results are benefit from the suppressed nonradiative recombination voltage loss, which is as low as 0.20 V. This value is the lowest value for OSCs so far and is comparable to high performance crystalline silicon and perovskite solar cells. These results show that OSCs have the potential to achieve comparable V_oc and voltage loss as inorganic photovoltaic technologies.     

Tailoring Triple‐Anion Perovskite Material for Indoor Light Harvesting with Restrained Halide Segregation and Record High Efficiency Beyond 36%

Indoor photovoltaics are promising to enable self‐powered electronic devices for the Internet of Things. Here, reported is a triple‐anion CH₃NH₃PbI_2?xBrCl_x perovskite film, of which the bandgap is specially designed for indoor light harvesting to achieve a record high efficiency of 36.2% with distinctive high open circuit voltage (V_oc) of 1.028 V under standard 1000 lux fluorescent light. The involvement of both bromide and chloride suppresses the trap‐states and nonradiative recombination loss, exhibiting a remarkable ideality factor of 1.097. The introduction of chloride successfully restrains the halide segregation of iodide and bromide, stabilizing the triple‐anion perovskite film. The devices show an excellent long‐term performance, sustaining over 95% of original efficiency under continuous light soaking over 2000 h. These findings show the importance and potential of I/Br/Cl triple‐anion perovskite with tailored bandgap and suppressed trap‐states in stable and efficient indoor light recycling.     

Modified PEDOT Layer Makes a 1.52 V Voc for Perovskite/PCBM Solar Cells

The work functions for charge transport layers in perovskite solar cells affect device performance significantly. In this work, the regular poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is modified by adding a polymer electrolyte PSS‐Na to improve its HTL function in perovskite solar cells. The modified PEDOT:PSS films (called m‐PEDOT:PSS) possess higher work function than the regular one. Its energy level matches the valence band of perovskite very well, leading to enhanced V_oc and PCE (power conversion efficiency). When CH₃NH₃PbI₃ is used as the light absorber, the cell with PEDOT:PSS HTL gives a V_oc of 0.96 V and a PCE of 12.35%, while the cell with m‐PEDOT:PSS layer gives a V_oc of 1.11 V and a PCE of 15.56%. Enhanced V_oc and PCE are also achieved when CH₃NH₃PbI₂Br or CH₃NH₃PbBr₃ is used as the light absorber. The m‐PEDOT:PSS/CH₃NH₃PbBr₃/PC₆₁BM solar cells demonstrate an outstanding V_oc of 1.52 V.     

A Novel Anion Doping for Stable CsPbI2Br Perovskite Solar Cells with an Efficiency of 15.56% and an Open Circuit Voltage of 1.30 V

The Cs‐based inorganic perovskite solar cells (PSCs), such as CsPbI₂Br, have made a striking breakthrough with power conversion efficiency (PCE) over 16% and potential to be used as top cells for tandem devices. Herein, I^? is partially replaced with the acetate anion (Ac^?) in the CsPbI₂Br framework, producing multiple benefits. The Ac^? doping can change the morphology, electronic properties, and band structure of the host CsPbI₂Br film. The obtained CsPbI_2?x Br(Ac)_x perovskite films present lower trap densities, longer carrier lifetimes, and fast charge transportation compared to the host CsPbI₂Br films. Interestingly, the CsPbI_2?x Br(Ac)_x PSCs exhibit a maximum PCE of 15.56% and an ultrahigh open circuit voltage (V_oc) of 1.30 V without sacrificing photocurrent. Notably, such a remarkable V_oc is among the highest values of the previously reported CsPbI₂Br PSCs, while the PCE far exceeds all of them. In addition, the obtained CsPbI_2?x Br(Ac)_x PSCs exhibit high reproducibility and good stability. The stable CsPbI_2?x Br(Ac)_x PSCs with high V_oc and PCE are desirable for tandem solar cell applications.     

Ultrathin Perovskite Monocrystals Boost the Solar Cell Performance

Grains and grain boundaries play key roles in determining halide perovskite‐based optoelectronic device performance. Halide perovskite monocrystalline solids with large grains, smaller grain boundaries, and uniform surface morphology improve charge transfer and collection, suppress recombination loss, and thus are highly favorable for developing efficient solar cells. To date, strategies of synthesizing high‐quality thin monocrystals (TMCs) for solar cell applications are still limited. Here, by combining the antisolvent vapor‐assisted crystallization and space‐confinement strategies, high‐quality millimeter sized TMCs of methylammonium lead iodide (MAPbI₃) perovskites with controlled thickness from tens of nanometers to several micrometers have been fabricated. The solar cells based on these MAPbI₃ TMCs show power conversion efficiency (PCE) of 20.1% which is significantly improved compared to their polycrystalline counterparts (PCE) of 17.3%. The MAPbI₃ TMCs show large grain size, uniform surface morphology, high hole mobility (up to 142 cm² V^?1 s^?1), as well as low trap (defect) densities. These properties suggest that TMCs can effectively suppress the radiative and nonradiative recombination loss, thus provide a promising way for maximizing the efficiency of perovskite solar cells.     

Improving Film Formation and Photovoltage of Highly Efficient Inverted‐Type Perovskite Solar Cells through the Incorporation of New Polymeric Hole Selective Layers

Two chemically tailored new conjugated copolymers, HSL1 and HSL2, were developed and applied as hole selective layers to improve the anode interface of fullerene/perovskite planar heterojunction solar cells. The introduction of polar functional groups on the polymer side chains increases the surface energy of the hole selective layers (HSLs), which promote better wetting with the perovskite films and lead to better films with full coverage and high crystallinity. The deep highest occupied molecular orbital levels of the HSLs align well with the valence band of the perovskite semiconductors, resulted in increase photovoltage. The high lying lowest unoccupied molecule orbital level provides sufficient electron blocking ability to prevent electrons from reaching the anode and reduces the interfacial trap‐assisted recombination at the poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)/perovskite interface, resulting in a longer charge‐recombination lifetime and shorter charge‐extraction time. In the presence of the HSLs, high‐performance CH₃NH₃PbI _x Cl_{3? x} perovskite solar cells with a power conversion efficiency (PCE) of 16.6% (V _oc: 1.07 V) and CH₃NH₃Pb(I_0.3Br_0.7) _x Cl_{3? x} cells with a PCE of 10.3% (V _oc: 1.34 V) can be realized.     

Porphyrin Sensitizers with Donor Structural Engineering for Superior Performance Dye‐Sensitized Solar Cells and Tandem Solar Cells for Water Splitting Applications

Zn(II)–porphyrin sensitizers, coded as SGT‐020 and SGT‐021 , are designed and synthesized through donor structural engineering. The photovoltaic (PV) performances of SGT sensitizer‐based dye‐sensitized solar cells (DSSCs) are systematically evaluated in a thorough SM315 as a reference sensitizer. The effect of the donor ability and the donor bulkiness on photovoltaic performances is investigated for establishing the structure–performance relationship in the platform of porphyrin‐triple bond‐benzothiadiazole‐acceptor sensitizers. By introducing a more bulky fluorene unit to the amine group in the SM315 , the power conversion efficiency (PCE) is enhanced with the increased short‐circuit current (J_sc) and open‐circuit voltage (V_oc), due to the improved light‐harvesting ability and the efficient prevention of charge recombination, respectively. As a consequence, a maximum PCE of 12.11% is obtained for SGT‐021 , whose PCE is much higher than the 11.70% PCE for SM315 . To further improve their maximum efficiency, the first parallel tandem DSSCs employing cobalt electrolyte in the top and bottom cells are demonstrated and an extremely high efficiency of 14% is achieved, which is currently the highest reported value for tandem DSSCs. The series tandem DSSCs give a remarkably high V_oc value of >1.83 V. From this DSSC tandem configuration, 7.4% applied bias photon‐to‐current efficiency is achieved for solar water splitting.     

Dual Interfacial Modifications Enable High Performance Semitransparent Perovskite Solar Cells with Large Open Circuit Voltage and Fill Factor

In this work, both anode and cathode interfaces of p‐i‐n CH₃NH₃PbI₃ perovskite solar cells (PVSCs) are simultaneously modified to achieve large open‐circuit voltage (V_oc) and fill factor (FF) for high performance semitransparent PVSCs (ST‐PVSCs). At the anode, modified NiO serves as an efficient hole transport layer with appropriate surface property to promote the formation of smooth perovskite film with high coverage. At the cathode, a fullerene bisadduct, C₆₀(CH₂)(Ind), with a shallow lowest unoccupied molecular orbital level, is introduced to replace the commonly used phenyl‐C₆₁‐butyric acid methyl ester (PCBM) as an alternative electron transport layer in PVSCs for better energy level matching with the conduction band of the perovskite layer. Therefore, the V_oc, FF and power conversion efficiency (PCE) of the PVSCs increase from 1.05 V, 0.74 and 16.2% to 1.13 V, 0.80 and 18.1% when the PCBM is replaced by C₆₀(CH₂)(Ind). With the advantages of high V_oc and FF, ST‐PVSCs are also fabricated using an ultrathin transparent Ag as cathode, showing an encouraging PCEs of 12.6% with corresponding average visible transmittance (AVT) over 20%. These are the highest PCEs reported for ST‐PVSCs with similar AVTs paving the way for using ST‐PVSCs as power generating windows.     

Significant Effect of Fluorination on Simultaneously Improving Work Function and Transparency of Anode Interlayer for Organic Solar Cells

Since the highest occupied molecular orbital (HOMO) level of donors in organic solar cells (OSCs) is being constantly downshifted for achieving high open‐circuit voltage (V_oc), a further enhancement of the anode work function (WF) is required. Herein, an effective approach of fluorination is demonstrated to simultaneously improve the WF and transparency for anode interlayer (AIL) material. By fluorination, in combination with the dialysis treatment in LiCl solution, the WF of PCP‐2F‐Li could be significantly enhanced from 4.86 to 5.0 eV, as compared to PCP‐Na. Meanwhile, the transparency of the polymer is also improved. As a result, PCP‐2F‐Li can be used to modify efficient active layers consisting of polymer donors with deep HOMO levels, such as PBDB‐T‐2F:IT‐4F, and an outstanding power conversion efficiency (PCE) of 12.7% is achieved in the corresponding device with a high V_oc of 0.84 V. This result represents the highest efficiency for the OSCs using a solution‐processed pH‐neutral AIL, which is beneficial to the low‐cost fabrication of high‐performance OSCs with improved stability. More importantly, PCP‐2F‐Li could be processed by blade coating for making large‐area device of 1 cm², and a PCE of 10.6% is achieved, bringing a promising prospect for the large‐area device fabrication.     

High Open-Circuit Voltage (1.197 V) in Large-Area (1 cm2) Inverted Perovskite Solar Cell via Interface Planarization and Highly Polar Self-Assembled Monolayer

The efficiency loss caused by area scaling is one of the key factors hindering the industrial development of perovskite solar cells. The energy loss and contact issues in the buried interface are the main reasons. Here, a new self-assembled monolayer (SAM), Ph-4PACz, with a large dipole moment (2.32 D) is obtained . It is found that Ph-4PACz with high polarity can improve the band alignment and minimize the energy loss , resulting in an open-circuit voltage (V_oc) as high as 1.2 V for 1.55 eV perovskite. However, when applied to large-area devices, the fill factor (FF) still suffered from significant attenuation. Therefore, alumina nanoparticles (Al₂O₃-NPs) are introduced to the interface between Ph-4PACz and rough FTO substrate to further improve the flatness , resulting in a conformal perovskite film with almost no voids in the buried interface, thus promoting low exciton binding energy, fast hot-carrier extraction and low non-radiative recombination. The final devices achieved a small-area power conversion efficiency (PCE) of 25.60% and a large-area (1 cm²) PCE of 24.61% (certified at 24.48%), which represents one of the highest PCE for single device ≥ 1 cm² area. Additionally, mini-modules and stability testing are also carried out to demonstrate the feasibility of commercialization.     

Hot‐Substrate Deposition of Hole‐ and Electron‐Transport Layers for Enhanced Performance in Perovskite Solar Cells

Charge transport layers play an important role in determining the power conversion efficiencies (PCEs) of perovskite solar cells (PSCs). However, it has proven challenging to produce thin and compact charge transport layers via solution processing techniques. Herein, a hot substrate deposition method capable of improving the morphology of high‐coverage hole‐transport layers (HTLs) and electron‐transport layers (ETLs) is reported. PSC devices using HTLs deposited on a hot substrate show improvement in the open‐circuit voltage (V_oc) from 1.041 to 1.070 V and the PCE from 17.00% to 18.01%. The overall device performance is then further enhanced with the hot substrate deposition of ETLs as the V_oc and PCE reach 1.105 V and 19.16%, respectively. The improved performance can be explained by the decreased current leakage and series resistance, which are present in PSCs with rough and discontinuous HTLs and ETLs.     

Achieving Both Enhanced Voltage and Current through Fine‐Tuning Molecular Backbone and Morphology Control in Organic Solar Cells

It is a great challenge to simultaneously improve the two tangled parameters, open circuit voltage (V_oc) and short circuit current density (J_sc) for organic solar cells (OSCs). Herein, such a challenge is addressed by a synergistic approach using fine‐tuning molecular backbone and morphology control simultaneously by a simple yet effective side chain modulation on the backbone of an acceptor–donor–acceptor (A–D–A)‐type acceptor. With this, two terthieno[3,2‐b]thiophene (3TT) based A–D–A‐type acceptors, 3TT‐OCIC with backbone modulation and 3TT‐CIC without such modification, are designed and synthesized. Compared with the controlled molecule 3TT‐CIC, 3TT‐OCIC shows power conversion efficiency (PCE) of 13.13% with improved V_oc of 0.69 V and J_sc of 27.58 mA cm^?2, corresponding to PCE of 12.15% with V_oc of 0.65 V and J_sc of 27.04 mA cm^?2 for 3TT‐CIC–based device. Furthermore, with effective near infrared absorption, 3TT‐OCIC is used as the rear subcell acceptor in a tandem device and gave an excellent PCE of 15.72%.     

Incorporating CsF into the PbI2 Film for Stable Mixed Cation‐Halide Perovskite Solar Cells

Adding a small amount of CsI into mixed cation‐halide perovskite film via a one‐step method has been demonstrated as an excellent strategy for high‐performance perovskite solar cells (PSCs). However, the one‐step method generally relies on an antisolvent washing process, which is hard to control and not suitable for fabricating large‐area devices. Here, CsF is employed and Cs is incorporated into perovskite film via a two‐step method. It is revealed that CsF can effectively diffuse into the PbI₂ seed film, and drastically enhances perovskite crystallization, leading to high‐quality Cs‐doped perovskite film with a very long photoluminescence carrier lifetime (1413 ns), remarkable light stability, thermal stability, and humidity stability. The fabricated PSCs show power conversion efficiency (PCE) of over 21%, and they are highly thermally stable: in the aging test at 60 °C for 300 h, 96% of the original PCE remains. The CsF incorporation process provides a new avenue for stable high‐performance PSCs.     

Record Open‐Circuit Voltage Wide‐Bandgap Perovskite Solar Cells Utilizing 2D/3D Perovskite Heterostructure

In this work, the authors realize stable and highly efficient wide‐bandgap perovskite solar cells that promise high power conversion efficiencies (PCE) and are likely to play a key role in next generation multi‐junction photovoltaics (PV). This work reports on wide‐bandgap (≈1.72 eV) perovskite solar cells exhibiting stable PCEs of up to 19.4% and a remarkably high open‐circuit voltage (V_OC) of 1.31 V. The V_OC‐to‐bandgap ratio is the highest reported for wide‐bandgap organic?inorganic hybrid perovskite solar cells and the V_OC also exceeds 90% of the theoretical maximum, defined by the Shockley–Queisser limit. This advance is based on creating a hybrid 2D/3D perovskite heterostructure. By spin coating n‐butylammonium bromide on the double‐cation perovskite absorber layer, a thin 2D Ruddlesden–Popper perovskite layer of intermediate phases is formed, which mitigates nonradiative recombination in the perovskite absorber layer. As a result, V_OC is enhanced by 80 mV.     

Simultaneous Improvement of Photovoltaic Performance and Stability by In Situ Formation of 2D Perovskite at (FAPbI3)0.88(CsPbBr3)0.12/CuSCN Interface

To solve the stability issues of perovskite solar cells (PSC), here a novel interface engineering strategy that a versatile ultrathin 2D perovskite (5‐AVA)₂PbI₄ (5‐AVA = 5‐ammoniumvaleric acid) passivation layer that is in situ incorporated at the interface between (FAPbI₃)_0.88(CsPbBr₃)_0.12 and the hole transporting CuSCN is reported. Surface analysis using X‐ray photoelectron spectroscopy confirms the formation of 2D perovskite. Hysteresis is reduced by the interfacial 2D layer, which could be ascribed to improvement of interfacial charge extraction efficiency, associated with suppression of recombination. Moreover, introduction of the interface passivating layer enhances the moisture stability and photostability as compared to the control perovskite film due to hydrophobic nature of 2D perovskite. The unencapsulated device retains 98% of the initial power conversion efficiency (PCE) after 63 d under moisture exposure of about 10% in the dark. A PCE of the control device is boosted from 13.72 to 16.75% as a consequence of enhanced open‐circuit voltage (V_oc) and fill factor along with slightly increased short‐circuit current density (J_sc), which results from reduced trap states of (FAPbI₃)_0.88(CsPbBr₃)_0.12 as evidenced by enhanced carrier lifetimes and charge extraction. The perovskite/hole transport material interface engineering gives insight into simultaneous improvements of PCE and device stability.     

Highly stable and Efficient Perovskite Solar Cells Based on FAMA‐Perovskite‐Cu:NiO Composites with 20.7% Efficiency and 80.5% Fill Factor

To solve critical issues related to device stability and performance of perovskite solar cells (PSCs), FA_0.026MA_0.974PbI_3?yCl_y‐Cu:NiO (formamidinium methylammonium (FAMA)‐perovskite‐Cu:NiO) and Al₂O₃/Cu:NiO composites are developed and utilized for fabrication of highly stable and efficient PSCs through fully‐ambient‐air processes. The FAMA‐perovskite‐Cu:NiO composite crystals prepared without using any antisolvents not only improve the perovskite film quality with large‐size crystals and less grain boundaries but also tailor optical and electronic properties and suppress charge recombination with reduction of trap density. A champion device based on the composites as light absorber and Al₂O₃/Cu:NiO interfacial layer between electron transport layer and active layer yields power conversion efficiency (PCE) of 20.67% with V_OC of 1.047 V, J_SC of 24.51 mA cm^?2, and fill factor of 80.54%. More importantly, such composite‐based PSCs without encapsulation show significant enhancement in long‐term air‐stability, thermal‐ and photostability with retaining 97% of PCE over 240 d under ambient conditions (25–30 °C, 45–55% humidity).     

3D–2D–0D Interface Profiling for Record Efficiency All‐Inorganic CsPbBrI2 Perovskite Solar Cells with Superior Stability

All‐inorganic CsPbBrI₂ perovskite has great advantages in terms of ambient phase stability and suitable band gap (1.91 eV) for photovoltaic applications. However, the typically used structure causes reduced device performance, primarily due to the large recombination at the interface between the perovskite, and the hole‐extraction layer (HEL). In this paper, an efficient CsPbBrI₂ perovskite solar cell (PSC) with a dimensionally graded heterojunction is reported, in which the CsPbBrI₂ material is distributed within bulk–nanosheet–quantum dots or 3D–2D–0D dimension‐profiled interface structure so that the energy alignment is optimized in between the valence and conduction bands of both CsPbBrI₂ and the HEL layers. Specifically, the valence‐/conduction‐band edge is leveraged to bend with synergistic advantages: the graded combination enhances the hole extraction and conduction efficiency with effectively decreased recombination loss during the hole‐transfer process, leading to an enhanced built‐in electric field, hence a high V_OC of as much as 1.19 V. The profiled structure induces continuously upshifted energy levels, resulting in a higher J_SC of as much as 12.93 mA cm^?2 and fill factor as high as 80.5%, and therefore record power conversion efficiency (PCE) of 12.39%. As far as it is known, this is the highest PCE for CsPbBrI₂ perovskite‐based PSC.