Chen Weijie

A major challenge in the characterization of perovskite solar cells is to quantify recombination losses caused by slow charge transport. Voltage-dependent photoluminescence is shown to provide an opportunity to quantitatively determine the current density lost due to recombination from short circuit to open circuit.

The enhancement of the fill factor in the current generation of perovskite solar cells is the key for further efficiency improvement. Thus, methods to quantify the fill factor losses are urgently needed. Two methods are presented to quantify losses due to the finite resistance of the semiconducting layers of the solar cell as well as its contacts. The first method is based on the comparison between the voltage in the dark and under illumination analyzed at equal recombination current density and results in a voltage-dependent series resistance. Furthermore, the method reveals the existence of a strong photoshunt under illumination. The second method is based on measuring the photoluminescence of perovskite solar cells as a function of applied voltage. Thereby, the recombination current is determined as a function of voltage from short circuit to open circuit, and the presence of the photoshunt is explained with a high resistance of the electron and/or hole transport layers combined with field screening in the absorber.

The underlying physics and limiting factors of low-performance and high-hysteresis perovskite solar cells are disclosed by a comprehensive optoelectronic simulation with ion migration, which enables the manipulation of the device as well as the realization of high power conversion efficiency and low hysteresis index in the experiment.

The hysteresis effect is a critical factor affecting the widespread application of perovskite solar cells (PSCs). To eliminate this adverse effect, it is necessary to uncover the underlying physics, which characterize the microscopic behaviors of electrons, holes, and ions within PSCs. Herein, addressing the hysteresis effect of PSCs, the migration mechanisms of mobile ions (i.e., anions and cations) within the perovskite layer is explored, the simulation model is developed, and the corresponding experiments are performed. The electromagnetic response, the transport of electrons, holes, anions, and cations, and the electrostatic characteristics determined by the charges are considered in detail. The simulation verifies that the performance degradation is indeed originating from the mobile ions, especially under a high ion concentration. The physical reason of the unbalanced performance under forward and reverse electric scans is presented by optoelectronic simulation. The manipulation of the hysteresis effect increasing the built-in electric field and reducing the hysteresis index (HI) of low ion concentration devices, but increased HI under a high ion concentration is further investigated. The simulation guides the fabrication of a normal-bandgap PSC, which achieves the reverse (forward) power-conversion efficiency up to 23.35% (22.22%) with a HI as low as 4.8%.

Herein, 4-fluorobenzenaminium (FPA⁺) as bulky organic cation is utilized, providing high polarity and strong hydrogen bonds to realize oriented crystal growth in 2D Ruddlesden–Popper (RP) CsPbI₃ film to obtain lower defect trap density and better morphology quality. Importantly, the optimized 2D RP CsPbI₃ film-based device delivers high power conversion efficiency of 15.18% with strengthened environmental stability.

Bulky organic cations exhibit significant roles in improving the phase stability of CsPbI₃ by reducing its dimension with higher steric hindrance. However, the insulative properties of organic cations impede the carrier transition and damage the device performance. Herein, a new aromatic cation of 4-fluorobenzenaminium (FPA⁺) in the 2D CsPbI₃ to act as a spacer cation, is reported. Based on the theoretical simulation and experimental characterization for materials properties, film quality, and device performance, the large dipole moment and electronic inductive effect of FPA⁺ cations improve the hydrogen bond between H and I atoms, which is beneficial to realizing controllable crystallization quality. Therefore, the whole quality of 2D CsPbI₃ film is improved with a larger grain size, compact morphology, and low trap density. As a result, the (FPA)₂Cs₄Pb₅I₁₆ perovskite solar cell delivers a power conversion efficiency of 15.18%, significantly higher than that of PA-based (14.32%) perovskite solar cells. Herein, an in-depth understanding of fluoro-substituted organic cations is provided and is beneficial to the design and synthesis of new organic molecules in 2D perovskite.

An ultrathin and dense phenol (Ph) self-assembly layer is first employed to anchor on the surface of polyethylenimine (PEI) to passivate the undesirable chemical reaction between PEI and the nonfullerene acceptors for highly efficient and stable organic solar cells.

The popular nonfullerene acceptors readily react with the amine group-containing low-work-function interfacial layer (polyethylenimine [PEI] or polyethylenimine ethoxylated [PEIE]), leading a severe “S” shape in the current density–voltage (J–V) characteristics of the nonfullerene organic solar cells (OSCs). Herein, a novel strategy is proposed to passivate this detrimental interfacial chemical reaction. Phenol (Ph) is anchored on the surface of PEI to form a thin and dense self-assembly layer, which can avoid a direct contact between the PEI and active layer. Moreover, the formed PEI–Ph bilayer cathode interface layer (CIL) can still low the work function of the bottom electrode. As a result, significant enhancement of the device performance is obtained for the PEI–Ph CIL-based nonfullerene OSCs and the “S” shapes in the J–V characteristics are removed. After Ph anchoring on the surface of PEI, the power conversion efficiencies are increased from 2.46% to 11.97% for the PTB7-Th:IEICO-4F active layer system and from 6.09% to 16.34% for the PM6:Y6 system, respectively. More importantly, the PEI–Ph CIL-based device displays a superior long-term and illumination stability.

A synergistic bulk passivation and interface modification strategy is developed for the fabrication of high-quality tin–lead mixed perovskite films (1.27 eV) and efficient solar devices by blade-coating. Owing to the significantly suppressed nonradiative charge recombination, the prepared solar cells give a high efficiency of 19.06% with an impressive open-circuit voltage of 0.837 V.

Thin films of tin–lead alloyed perovskites are drawing growing attention, mainly owing to their tunable bandgaps in delivering efficient single- and multi-junction photovoltaic devices. The rapid efficiency advancement of Sn–Pb perovskite devices has been dependent primarily on improving the crystal quality of perovskite films via retarding oxidation of Sn²⁺. Herein, it is demonstrated that in addition to obtaining high-quality Sn–Pb perovskite thin films, reducing nonradiative recombination losses at interfaces is equally important for realizing efficient solar cells. An aromatic amine is first introduced to passivate the grain boundary in printed Sn–Pb perovskite films, which boosts the open-circuit voltage (V _OC) of the solar devices from 700 to 766 mV. Further enhancement of the V _OC to 814 mV and finally to 837 mV is realized by forming a 2D/3D-layered heterojunction and doping the hole extraction layer with a polyelectrolyte, respectively, benefiting from the largely suppressed nonradiative recombination losses at interfaces. Eventually, the mixed Sn–Pb perovskite devices with a bandgap of ≈1.27 eV yield a high efficiency of 19.06% and in parallel show improved shelf and light-soaking stability.

A new approach for reliable performance evaluation of integrated solar charging systems is presented. It is applied to a three-electrode photosupercapacitor produced by integration of a high-performance organic solar cell with a mesoporous nitrogen-doped carbon nanosphere-based supercapacitor in a single device. The analysis shows 2% cycle efficiency and an unprecedently high photoelectrochemical energy conversion efficiency of 17%.

The global trend toward automatization and miniaturization of smart devices has triggered the development of reliable off-grid power sources with low economic and environmental impact. Such autonomy can be provided when a photovoltaic cell is integrated with an electrochemical double-layer capacitor in one monolithic power pack. This work demonstrates a reliable and straightforward approach to monolithically integrate high-performance organic solar cells with mesoporous nitrogen-doped carbon nanosphere-based supercapacitors in a single device with a three-electrode configuration. To assess the efficiency of the device, a novel approach is presented that relies on the direct monitoring of both integrating parts during illuminated and dark phases and accounts for possible losses. The evaluation with the standard literature approach shows an outstanding performance of the integrated photosupercapacitor with a peak photoelectrochemical energy conversion efficiency of 17%. However, this type of efficiency does not properly represent the real overall efficiency of the device. Based on the newly developed efficiency calculation, a more modest overall cycle efficiency of 2% is obtained, which represents the overall performance of the integrated device in a better way. This versatile evaluation approach is applicable for all kinds of integrated multifunctional photoconversion–storage systems.

Publication date: November 2022

Source: Nano Energy, Volume 102

Author(s): Shuai Zhang, Fuzhen Bi, Jianhua Han, Chenyu Shang, Xiao Kang, Xichang Bao

Donor alloy strategy is proposed to tune chare transfer (CT) state erergy and thus E _loss for boosting organic solar cells (OSCs) efficiency. Together with optimal morphology, ternary OSCs deliver an outstanding efficiency of 19.22% with significantly improved open-circuit voltage (V _oc) of 0.910 V, the highest value for over 19% efficiency OSCs.

Abstract

The large energy loss (E _loss) is one of the main obstacles to further improve the photovoltaic performance of organic solar cells (OSCs), which is closely related to the charge transfer (CT) state. Herein, ternary donor alloy strategy is used to precisely tune the energy of CT state (E _CT) and thus the E _loss for boosting the efficiency of OSCs. The elevated E _CT in the ternary OSCs reduce the energy loss for charge generation (ΔE _CT), and promote the hybridization between localized excitation state and CT state to reduce the nonradiative energy loss (ΔE _nonrad). Together with the optimal morphology, the ternary OSCs afford an impressive power conversion efficiency of 19.22% with a significantly improved open-circuit voltage (V _oc) of 0.910 V without sacrificing short-cicuit density (J _sc) and fill factor (FF) in comparison to the binary ones. This contribution reveals that precisely tuning the E _CT via donor alloy strategy is an efficient way to minimize E _loss and improve the photovoltaic performance of OSCs.

A universal perovskite surface passivation method using 2,5-thiophenedicarboxylic acid is developed, by which the V _OC of different CsPbX₃ solar cells are highly enhanced, leaving extremely small V _OC deficits.

Abstract

In comparison to hybrid perovskite solar cells (PSCs), all-inorganic CsPbX₃ PSCs suffer from larger V _OC deficits, leading to inferior efficiency. The perovskite surface defects like iodine vacancy (V_I) are the main sources of nonradiative recombination causing a V _OC deficit. Here, 2,5-thiophenedicarboxylic acid (TDCA) is used to passivate the surface V_I through the strong coordination interaction between the thiophene unit of TDCA and the undercoordinated Pb²⁺ of perovskite. TDCA passivation also elevates the perovskite surface valence band position, leading to a better interfacial energy alignment. Consequently, the V _OC of CsPbI_2.25Br_0.75 PSCs is remarkably improved from 1.36 to 1.43 V (efficiency from 15.55% to 16.72%), reaching 92% (record-high among CsPbX₃ PSCs) of the Shockley–Queisser V _OC limit. This method also promotes the V _OC of CsPbI_1.5Br_1.5 cell from 1.42 to 1.51 V (90% of the limit) and CsPbIBr₂ cell from 1.44 to 1.54 V (87% of the limit), demonstrating its universality for CsPbX₃ perovskites.

The overview and outlook on graphene- and carbon nanotube-applied perovskite solar cells for both single-junction and tandem applications in this review provide an insight to research strategies for nanocarbons and optoelectronics. The versatile roles and synthesis methods of applied nanocarbons in perovskite solar cells open a gateway to next-generation energy harvesting devices in terms of both performance and functionality.

Abstract

Nanocarbon materials, such as graphene and carbon nanotubes (CNTs), have attracted considerable attention as the main or supplementary components in various optoelectronics boosting the device performance and improving the process conditions. Specifically, their application to perovskite solar cells, which are among the most promising photovoltaic devices acknowledged for eco-friendly energy generation, has significantly impacted the current standing of metal halide perovskite-based devices. The uniqueness of the nanocarbon applications can be attributed to their outstanding optical, electrical, chemical and mechanical properties, which conventional materials do not possess. This review overviews past and present reports on graphene- and CNT-incorporated perovskite solar cells. Versatile roles and various synthetic methodologies of the applied nanocarbons in perovskite solar cells, including the material growth methods and sources, and functions as transparent electrodes, charge-transporting layers, interfacial layers, additives and encapsulants, are categorized and graphically illustrated. The discussion expands from single-junction to tandem applications with silicon solar cells, where the nanocarbon materials also play an equally important yet divergent function. Applications of each graphene and CNTs to the silicon-perovskite tandem solar cells are interpreted in terms of what roles they play and how they solve the conventional problems. This review serves as the guideline for the photovoltaics researchers in advancing devices using nanocarbons.

Herein, a dual interfacial modification strategy is designed through placing Nb₂CT_OH and Nb₂CT_O at the SnO₂/perovskite and perovskite/Spiro-OMeTAD interfaces, respectively. The optimized perovskite solar cells (PSCs) achieve a superior power conversion efficiency (PCE) of 24.11% with remarkable open-circuit voltage (V _OC) (1.253 V) and fill factor (81.07%). Such a PCE value is by far the highest for PSCs employing MXene materials.

Abstract

The open-circuit voltage (V _OC) and fill factor (FF) of perovskite solar cells (PSCs) are detrimentally weakened by carrier loss at the perovskite/charge transport layers (CTLs) interfaces. Herein, a dual interfacial modification strategy via placing Nb₂CT _x nanosheets with tailored optoelectrical properties induced by manipulating surface terminal groups at both perovskite/CTLs interfaces is employed. Such tactics not only concurrently implement carrier mobility enhancement of CTLs and interface energy-levels offsets reduction. More importantly, electrical simulation indicates that the Nb₂CT _x with O terminal groups located at grain boundaries of the perovskite layer, can more efficiently conduct hole current to the hole transport layer, therefore achieving charge-carrier transport balance in device. As a result, the synergy effect effectively elevates both the V _OC and FF of the cells, reaching maximum values of 1.253 V and 81.07%, respectively, finally delivering progressively increased device power conversion efficiency (PCE) of 24.11% with negligible hysteresis. This PCE value ranks in the highest values to date for PSCs employing MXenes materials. Moreover, the optimized devices show better thermal and light stability than control devices. This work demonstrates a simple and effective dual interfacial modification method utilizing Nb₂CT _x for photovoltaic field, involving photodetectors, light-emitting diodes, sensors, etc.

Pentafluoro-phenylhydrazine (5F-PHZ) surface treatment ameliorates the surface chemistries, interface band alignment, and optoelectronic properties as a consequence of stronger halogen bonding with fluoroarene moieties and NH–NH₂ terminals to the perovskite surface and its interface. The resulting perovskite solar cells with supramolecular interfacial passivation exhibit a device efficiency of 22.29 % (area ≈ 1 cm²) with superior operational thermal stability forming a robust interface.

Abstract

Perovskite solar cells (PSCs) with state-of-the-art efficiencies contain thermally unstable methylammonium (MA). Here, interfacial passivation with pentafluorophenylhydrazine (5F-PHZ) to fabricate efficient and stable MA/Br-free PSCs is introduced. The 5F-PHZ surface treatment quenches the PbI₂ and δ-perovskite phase formed in the pristine film. The surface passivation ameliorates the film chemistries at the surface with modulation of interface band alignment as a consequence of halogen bonding with fluoroarene moieties or NH–NH₂ terminals. This results in a much longer carrier lifetime with the passivation at the surface and grain boundaries trap centers. As a result, it boosts the power conversion efficiency (PCE) (area ≈ 1 cm²) from 18.10% to 22.29% (V _OC ≈ 1.096–1.178 V) with superior operational thermal stability. A certified PCE of 21.01% with a large area of ≈1.026 cm² is also achieved. It is found that the surface passivation forms an interfacial embedded layer subsequent to attenuation of defect densities and suppression of ion migration, which is supported by density-function-theory calculation. Importantly, this approach is effective in enhancing the PCE of narrow and wide bandgap perovskite systems. Thus, this work opens up a new technique for interface modulation with fluoroarene functional derivatives to achieve superior device performance and stability.

Intermediary electron acceptor channels are constructed for manipulating charge transfer and transport, via combing two non-fullerene acceptors with less miscibility, which synergistically improves V _oc and J _sc, and enables ternary organic photovoltaic to exhibit a high efficiency of 19.3%.

Abstract

Balancing and improving the open-circuit voltage (V _oc) and short-circuit current density (J _sc) synergistically has always been the critical point for organic photovoltaics (OPVs) to achieve high efficiencies. Here, this work adopts a ternary strategy to regulate the trade-off between V _oc and J _sc by combining the symmetric-asymmetric non-fullerene acceptors that differ at terminals and alkyl side chains to build the ternary OPV (TOPV). It is noticed that the reduced energy disorder and the enhanced luminescence efficiency of TOPV enable a mitigated energy loss and a higher V _oc. Meanwhile, the third component, which is distributed at the host donor–acceptor interface, acts as the charge transport channel. The prolonged exciton lifetime, the boosted charge mobility, and the depressed charge recombination promote the TOPV to obtain an improved J _sc. Finally, with synergistically improved V _oc and J _sc, the TOPV delivers an optimal efficiency of 19.26% (certified as 19.12%), representing one of the highest values reported so far.

Network topology derived from grain subdivision and grain slip enables simultaneous robust toughness and strength of perovskite films with the elongation at break of 5.02% and the fracture strength of 55.25 MPa, respectively. The flexible solar cells achieve a champion power conversion efficiency of 20.01% and remaining 90% of the initial efficiency after bending 6000 cycles at the 2 mm curvature radius.

Abstract

The toughness and strength are generally mutually exclusive for most materials. Although the biological materials in nature such as wood, bone, and nacre exhibit outstanding toughness by forming hierarchical multiscale (nano to macro) structures, it is a huge challenge to simultaneously obtain excellent strength and toughness from material synthesis. Here, one kind of network topology is observed by introducing sodium hyaluronate into organometallic halide perovskite film to greatly improve its strength and toughness. The grain slip and grain subdivision under tensile stress are schemed to dissipate the system energy and endow the perovskite film with remarkable toughness. Meanwhile, the subdivided grains linked by sodium hyaluronate through strong interaction result in high strength of perovskite film. As a result, the perovskite films exhibit robust enhancements with the elongation at break from 1.58% to 5.02% and the fracture strength from 23.13 to 55.25 MPa. It is worth noting that the efficiency of inverted flexible perovskite solar cells reaches 20.01% as well as maintains 90% of the initial efficiency after 6000 cycles of bending at a 2 mm curvature radius. This work devises a topology structure to overcome the conflict between toughness and strength of perovskite films for wearable electronics.

In this review, first, the crystallization characteristics of CsPbX ₃ perovskites are briefly introduced. Second, the recent exciting progress in the crystallization modulation strategies for high-quality CsPbX ₃ films and high-performance solar cells is summarized and discussed in detail. The advantages of different strategies, including annealing engineering, solvent engineering, precursor engineering, composition engineering, and interface engineering, are highlighted.

Abstract

All-inorganic CsPbX ₃ (X = I, Br, Cl or their mixtures) perovskites attract enormous attention in recent years due to their excellent optoelectronic properties, outstanding thermal/light stability, and wide range of applications in electronic devices. Encouragingly, the reported power conversion efficiency of CsPbX ₃ perovskite solar cells (PSCs) rockets up from 2.9% in 2015 to the present 21.0%. In order to further promote the performance of CsPbX ₃ PSCs toward the Shockley–Queisser efficiency limit, it is important to optimize the quality of perovskite films by crystallization kinetics modulation and defect suppression. In this review, first, some fundamental information about all-inorganic CsPbX ₃ perovskites is briefly introduced, including the crystallization mechanism, growth mode, crystal structure, and phase stability as well as possible defects and their effects on device performance. Second, the recent exciting progress of the crystallization modulation strategies for high-quality CsPbX ₃ films is summarized and discussed in detail. The advantages of different strategies, including annealing engineering, solvent engineering, precursor engineering, composition engineering, and interface engineering, are highlighted. Finally, methods for improving the efficiency of inorganic PSCs are discussed, and the future development prospects of inorganic PSCs are also outlined.

Sb₂S₃ planar solar cell with a power conversion efficiency first exceeding 8% is achieved based on the high-quality Sb₂S₃ absorber film fabricated using a novel multi-sulfur source collaborative chemical bath deposition technology.

Abstract

Sb₂S₃ as a light-harvesting material has attracted great attention for applications in both single-junction and tandem solar cells. Such solar cell has been faced with current challenge of low power conversion efficiency (PCE), which has stagnated for 8 years. It has been recognized that the synthesis of high-quality absorber film plays a critical role in efficiency improvement. Here, using fresh precursor materials for antimony (antimony potassium tartrate) and combined sulfur (sodium thiosulfate and thioacetamide), a unique chemical bath deposition procedure is created. Due to the complexation of sodium thiosulfate and the advantageous hydrolysis cooperation between these two sulfur sources, the heterogeneous nucleation and the S^2- releasing processes are boosted. As a result, there are noticeable improvements in the deposition rate, film morphology, crystallinity, and preferred orientations. Additionally, the improved film quality efficiently lowers charge trapping capacity, suppresses carrier recombination, and prolongs carrier lifetimes, leading to significantly improved photoelectric properties. Ultimately, the PCE exceeds 8% for the first time since 2014, representing the highest efficiency in all kinds of Sb₂S₃ solar cells to date. This study is expected to shed new light on the fabrication of high-quality Sb₂S₃ film and further efficiency improvement in Sb₂S₃ solar cells.

New synthesized non-conjugated polyelectrolyte is introduced as an interfacial layer between the charge-transport layer and perovskite absorbent, which significantly reduce both bulk and interfacial nonradiative recombination losses, but also aligns the interface's energy level. The modified perovskite solar cells show a power conversion efficiency of 24.4% (open-circuit voltage 1.21 V) with negligible hysteresis and superior operational stability.

Abstract

Suppressing nonradiative recombination at the interface between the organometal halide perovskite (PVK) and the charge-transport layer (CTL) is crucial for improving the efficiency and stability of PVK-based solar cells (PSCs). Here, a new bathocuproine (BCP)-based nonconjugated polyelectrolyte (poly-BCP) is synthesized and this is introduced as a “dual-side passivation layer” between the tin oxide (SnO₂) CTL and the PVK absorber. Poly-BCP significantly suppresses both bulk and interfacial nonradiative recombination by passivating oxygen-vacancy defects from the SnO₂ side and simultaneously scavenges ionic defects from the other (PVK) side. Therefore, PSCs with poly-BCP exhibits a high power conversion efficiency (PCE) of 24.4% and a high open-circuit voltage of 1.21 V with a reduced voltage loss (PVK bandgap of 1.56 eV). The non-encapsulated PSCs also show excellent long-term stability by retaining 93% of the initial PCE after 700 h under continuous 1-sun irradiation in nitrogen atmosphere conditions.

Intrinsic (trap-free) field-effect transistors based on epitaxial single-crystalline CsPbBr₃ perovskite films are reported. Extensive structural, electrical, and gated Hall-effect characterization confirms outstanding quality of the material and a nearly ideal transistor behavior. Hole mobility of 30 cm² V⁻¹ s⁻¹ at room temperature, monotonically increasing on cooling to 250 cm² V⁻¹ s⁻¹ at 50 K, is measured in these transistors.

Abstract

The first experimental realization of the intrinsic (not dominated by defects) charge conduction regime in lead-halide perovskite field-effect transistors (FETs) is reported. The advance is enabled by: i) a new vapor-phase epitaxy technique that results in large-area single-crystalline cesium lead bromide (CsPbBr₃) films with excellent structural and surface properties, including atomically flat surface morphology, essentially free from defects and traps at the level relevant to device operation; ii) an extensive materials analysis of these films using a variety of thin-film and surface probes certifying the chemical and structural quality of the material; and iii) the fabrication of nearly ideal (trap-free) FETs with characteristics superior to any reported to date. These devices allow the investigation of the intrinsic FET and (gated) Hall-effect carrier mobilities as functions of temperature. The intrinsic mobility is found to increase on cooling from ≈30 cm² V⁻¹ s⁻¹ at room temperature to ≈250 cm² V⁻¹ s⁻¹ at 50 K, revealing a band transport limited by phonon scattering. Establishing the intrinsic (phonon-limited) mobility provides a solid test for theoretical descriptions of carrier transport in perovskites, reveals basic limits to the technology, and points to a path for future high-performance perovskite electronic devices.

Publication date: 10 November 2022

Source: Chem, Volume 8, Issue 11

Author(s): Gao-Yuan Chen, Zhen-Dong Guo, Xin-Gao Gong, Wan-Jian Yin

Nature Energy, Published online: 29 August 2022; doi:10.1038/s41560-022-01102-w

Publication date: 10 November 2022

Source: Chem, Volume 8, Issue 11

Author(s): He Zhu, Junjie Ma, Pengwei Li, Shuangquan Zang, Yiqiang Zhang, Yanlin Song

Orderly oxidation of CsPbI₂Br film in moist air leads to more efficient defect passivation in film by grain boundary oxidation, and higher hole extraction efficiency in device via the energy band coupling between CsPbI₂Br and oxidation product CsPbIBr₂. The champion cell achieves an efficiency of 15.27%, and a certified efficiency of 14.7%, which is a record efficiency for CsPbI₂Br C-PSCs.

Abstract

Large energy loss (E _loss) caused by defect-assisted recombination makes the photovoltaic performance of carbon-based perovskite solar cells (C-PSCs) inferior to that of metal-electrode ones. Herein, the influence of environmental factors (moisture and oxygen) on defect management during re-annealing process of CsPbI₂Br crystalline films is systematically studied. Density functional theory and experimental results indicate that moisture in the air can significantly reduce the oxidation kinetics of crystalline films, resulting in orderly oxidation. Concomitantly, the oxidation decomposition products PbO and CsPbIBr₂ are enriched at grain boundaries, passivating surface defects efficiently. Simultaneously, energy band coupling between CsPbI₂Br and CsPbIBr₂ improves the hole extraction efficiency. The photovoltage of corresponding C-PSCs is increased from 1.05 to 1.32 V, indicating a reduced E _loss derived from orderly oxidation strategy. Correspondingly, the champion cell achieves an efficiency of 15.27%, and a certified efficiency of 14.7%, which is a new record efficiency for CsPbI₂Br C-PSCs.