Over 21% Efficient Cesium Lead Triiodide Solar Cell Enabled by Molten Salt Accelerating the Crystallization Processes.

High-quality CsPbI3 with low defect density is indispensable for acquiring excellent photoelectric performance. Meticulous regulation of the CsPbI3 crystal growth processes is both feasible and efficacious in enhancing the quality of perovskite films. In this study, the cesium formate (CsFo) is introduced. On one hand, its low melting point can induce the crystallization processes at a low level of energy consumption. On the other hand, the pseudo-halide anion can participate in the passivation of iodide vacancies, as the formate anion exhibits a relatively higher affinity with iodide vacancies compared to other halides. Consequently, the introduction of CsFo enhances the quality of CsPbI3 thin films by altering the crystallization process and curbing defect formation. As a result, a steady-state output efficiency of 21.23% and an open-circuit voltage (Voc) as high as 1.25 V are achieved, with both parameters ranking among the highest for this type of solar cell.

Enhanced Interfacial Modification by Ordered Discotic Liquid Crystals for Thermotolerance Perovskite Solar Cells.

Traditionally used phenylethylamine iodide (PEAI) and its derivatives, such as ortho-fluorine o-F-PEAI, in interfacial modification, are beneficial for perovskite solar cell (PSC) efficiency but vulnerable to heat stability above 85 °C due to ion migration. To address this issue, we propose a composite interface modification layer incorporating the discotic liquid crystal 2,3,6,7,10,11-hexa(pentoxy)triphenylene (HAT5) into o-F-PEAI. The triphenyl core in HAT5 promotes π-π stacking self-assembly and enhances its interaction with o-F-PEAI, forming an oriented columnar phase that improves hole extraction along the one-dimensional direction. HAT5 repairs structural defects in the interfacial layer and retains the layered structure to inhibit ion migration after annealing. Ultimately, our approach increases the efficiency of solar cells from 23.36% to 25.02%. The thermal stability of the devices retains 80.1% of their initial efficiency after aging at 85 °C for 1008 hours without encapsulation. Moreover, the optimized PSCs maintained their initial efficiency of 82.4% after aging under one sunlight exposure for 1008 hours. This study provides a novel strategy using composite materials for interface modification to enhance the thermal and light stability of semiconductor devices.

Rational Design of A-Site Cation for High Performance Lead-Free Perovskite X-Ray Detectors.

Design of hypotoxic lead-free perovskites, e.g. Bismuth(Bi)-based perovskites, is much beneficial for commercialization of perovskite X-ray detectors due to their strong radiation absorption. Nevertheless, the design principles governing the selection of A-site cations for achieving high-performance X-ray detectors remain elusive. Here, seven molecules (methylamine MA, amine NH3, dimethylbiguanide DGA, phenylethylamine PEA, 4-fluorophenethylamine p-FPEA, 1,3-propanediamine PDA, and 1,4-butanediamine BDA) and calculated their dipole moments and interaction strength with metal halide (BiI3) are selected. The first-principles calculations and related spectroscopy measurements confirm that organic molecules (DGA) with large dipole moments can have strong interactions with perovskite octahedron and improve the carrier transport between the organic and inorganic clusters. Consequently, zero-dimensional single crystal (SC) (DGA)BiI5∙H2O is synthesized. The (DGA)BiI5∙H2O SCs demonstrate an exceptional carrier mobility-lifetime product of 6.55 × 10-3 cm2 V-1, resulting in the high sensitivity of 5879.4 µCGyair -1cm-2, featuring a low detection limit (4.7 nGyair s-1) and remarkable X-ray irradiation stability even after 100 days of aging at a high electric field (100 V mm-1). Furthermore, the (DGA)BiI5∙H2O SCs for imaging, achieving a notable spatial resolution of 5.5 lp mm-1 are applied. This investigation establishes a pathway for systematically screening A-site cations to design low-dimensional SCs for high-performance X-ray detection.

25.71%-Efficiency FACsPbI3 Perovskite Solar Cells Enabled by A Thiourea-based Isomer.

Various isomers have been developed to regulate the morphology and reduce defects in state-of-the-art perovskite solar cells. To insight the structure-function-effect correlations for the isomerization of thiourea derivatives on the performance of the perovskite solar cells (PSCs), we developed two thiourea derivatives [(3,5-dichlorophenyl)amino]thiourea (AT) and N-(3,5-dichlorophenyl)hydrazinecarbothioamide (HB). Supported by experimental and calculated results, it was found that AT can bind with undercoordinated Pb2+ defect through synergistic interaction between N1 and C=S group with a defect formation energy of 1.818 eV, which is much higher than that from the synergistic interaction between two -NH- groups in HB and perovskite (1.015 eV). Moreover, the stronger interaction between AT and Pb2+ regulates the crystallization process of perovskite film to obtain a high-quality perovskite film with high crystallinity, large grain size, and low defect density. Consequently, the AT-treated FACsPbI3 device engenders an efficiency of 25.71% (certified as 24.66%), which is greatly higher than control (23.74%) and HB-treated FACsPbI3 devices (25.05%). The resultant device exhibits a remarkable stability for maintaining 91.0% and 95.2% of its initial efficiency after aging 2000 h in air condition or tracking at maximum power point for 1000 h, respectively.

One-Stone-For-Three-Birds Strategy Using a Fullerene Modifier for Efficient and Stable Inverted Perovskite Solar Cells.

The electron extraction from perovskite/C60 interface plays a crucial role in influencing the photovoltaic performance of inverted perovskite solar cells (PSCs). Here, we develop a one-stone-for-three-birds strategy via employing a novel fullerene derivative bearing triple methyl acrylate groups (denoted as C60-TMA) as a multifunctional interfacial layer to optimize electron extraction at the perovskite/C60 interface. It is found that the C60-TMA not only passivates surface defects of perovskite via coordination interactions between C=O groups and Pb2+ cations but also bridge electron transfer between perovskite and C60. Moreover, it effectively induces the secondary grain growth of the perovskite film through strong bonding effect, and this phenomenon has never been observed in prior art reports on fullerene related studies. The combination of the above three upgrades enables improved perovskite film quality with increased grain size and enhanced crystallinity. With these advantages, C60-TMA treated PSC devices exhibit a much higher power conversion efficiency (PCE) of 24.89% than the control devices (23.66%). Besides, C60-TMA benefits improved thermal stability of PSC devices, retaining over 90% of its initial efficiency after aging at 85 °C for 1200 h, primarily due to the reinforced interfacial interactions and improved perovskite film quality.

Customizing Aniline-Derived Molecular Structures to Attain beyond 22% Efficient Inorganic Perovskite Solar Cells.

The characteristics of the soft component and the ionic-electronic nature in all-inorganic CsPbI3-xBrxperovskite typically lead to a significant number of halide vacancy defects and ions migration, resulting in a reduction in both photovoltaic efficiency and stability. Herein, we present a tailored approach in which both anion-fixation and undercoordinated-Pb passivation are achieved in situ during crystallization by employing a molecule derived from aniline, specifically 2-methoxy-5-trifluoromethylaniline (MFA), to address the above challenges. The incorporation of MFA into the perovskite film results in a pronounced inhibition of ion migration, a significant reduction in trap density, an enhancement in grain size, an extension of charge carrier lifetime, and a more favorable alignment of energy levels. These advantageous characteristics contribute to achieving a champion power conversion efficiency (PCE) of 22.14% for the MFA-based CsPbI3-xBrx perovskite solar cells (PSCs), representing the highest efficiency reported thus far for this type of inorganic metal halide perovskite solar cells, to the best of our knowledge. Moreover, the resultant PSCs exhibits higher environmental stability and photostability. This strategy is anticipated to offer significant advantages for large-area fabrication, particularly in terms of simplicity.

Enhancement of Photodetector Characteristics by Zn-Porphyrin-Passivated MAPbBr3 Single Crystals.

Perovskite single crystals have garnered significant interest in photodetector applications due to their exceptional optoelectronic properties. The outstanding crystalline quality of these materials further enhances their potential for efficient charge transport, making them promising candidates for next-generation photodetector devices. This article reports the synthesis of methyl ammonium lead bromide (MAPbBr3) perovskite single crystal (SC) via the inverse-temperature crystallization method. To further improve the performance of the photodetector, Zn-porphyrin (Zn-PP) was used as a passivating agent during the growth of SC. The optical characterization confirmed the enhancement of optical properties with Zn-PP passivation. On single-crystal surfaces, integrated photodetectors are fabricated, and their photodetection performances are evaluated. The results show that the single-crystalline photodetector passivated with 0.05% Zn-PP enhanced photodetection properties and rapid response speed. The photoelectric performance of the device, including its responsivity (R), external quantum efficiency (EQE), detective nature (D), and noise-equivalent power (NEP), showed an enhancement of the un-passivated devices. This development introduces a new potential to employ high-quality perovskite single-crystal-based devices for more advanced optoelectronics.

Defect Passivation and Crystallization Regulation for Efficient and Stable Formamidinium Lead Iodide Solar Cells with Multifunctional Amidino Additive.

Amidino-based additives show great potential in high-performance perovskite solar cells (PSCs). However, the role of different functional groups in amidino-based additives have not been well elucidated. Herein, two multifunctional amidino additives 4-amidinobenzoic acid hydrochloride (ABAc) and 4-amidinobenzamide hydrochloride (ABAm) are employed to improve the film quality of formamidinium lead iodide (FAPbI3) perovskites. Compared with ABAc, the amide group imparts ABAm with larger dipole moment and thus stronger interactions with the perovskite components, i.e., the hydrogen bonds between N…H and I- anion and coordination bonds between C = O and Pb2+ cation. It strengthens the passivation effect of iodine vacancy defect and slows down the crystallization process of α-FAPbI3, resulting in the significantly reduced non-radiative recombination, long carrier lifetime of 1.7 µs, uniformly large crystalline grains, and enhances hydrophobicity. Profiting from the improved film quality, the ABAm-treated PSC achieves a high efficiency of 24.60%, and maintains 93% of the initial efficiency after storage in ambient environment for 1200 hours. This work provides new insights for rational design of multifunctional additives regarding of defect passivation and crystallization control toward highly efficient and stable PSCs.

Dense Perovskite Thick Film Enabled by Saturated Solution Filling for Sensitive X-ray Detection and Imaging.

Thick polycrystalline perovskite films synthesized by using solution processes show great potential in X-ray detection applications. However, due to the evaporation of the solvent, many pinholes and defects appear in the thick films, which deteriorate their optoelectronic properties and diminish their X-ray detection performance. Therefore, the preparation of large area and dense perovskite thick films is desired. Herein, we propose an effective strategy of filling the pores with a saturated precursor solution. By adding the saturated perovskite solution to the polycrystalline perovskite thick film, the original perovskite film will not be destroyed because of the solution-solute equilibrium relationship. Instead, it promotes in situ crystal growth within the thick film during the annealing process. The loosely packed grains in the original thick perovskite film are connected, and the pores and defects are partially filled and fixed. Finally, a much denser perovskite thick film with improved optoelectronic properties has been obtained. The optimized thick film exhibits an X-ray sensitivity of 1616.01 µC Gyair-1 cm-2 under an electric field of 44.44 V mm-1 and a low detection limit of 28.64 nGyair s-1 under an electric field of 22.22 V mm-1. These values exceed the 323.86 µC Gyair-1 cm-2 and 40.52 nGyair s-1 of the pristine perovskite thick film measured under the same conditions. The optimized thick film also shows promising working stability and X-ray imaging capability.

Fusing Science with Industry: Perovskite Photovoltaics Moving Rapidly into Industrialization.

The organic-inorganic lead halide per materials have emerged as highly promising contenders in the field of photovoltaic technology, offering exceptional efficiency and cost-effectiveness. The commercialization of perovskite photovoltaics hinges on successfully transitioning from lab-scale perovskite solar cells to large-scale perovskite solar modules (PSMs). However, the efficiency of PSMs significantly diminishes with increasing device area, impeding commercial viability. Central to achieving high-efficiency PSMs is fabricating uniform functional films and optimizing interfaces to minimize energy loss. This review sheds light on the path toward large-scale PSMs, emphasizing the pivotal role of integrating cutting-edge scientific research with industrial technology. By exploring scalable deposition techniques and optimization strategies, the advancements and challenges in fabricating large-area perovskite films are revealed. Subsequently, the architecture and contact materials of PSMs are delved while addressing pertinent interface issues. Crucially, efficiency loss during scale-up and stability risks encountered by PSMs is analyzed. Furthermore, the advancements in industrial efforts toward perovskite commercialization are highlighted, emphasizing the perspective of PSMs in revolutionizing renewable energy. By highlighting the scientific and technical challenges in developing PSMs, the importance of combining science and industry to drive their industrialization and pave the way for future advancements is stressed.

2D Metal Enabled Weak Fermi Level Pinning Effect and Tunable Charge Injection in Contacts with Inorganic 2D Perovskites.

Tow-dimensional (2D) perovskites have invoked extensive interest because of their good stability and intriguing optoelectronic properties. However, in practical applications, the hampered carrier transportation imposed by the vertical array of large dielectric organic cations and the generally seen Fermi level pinning (FLP) effect in conventional metal-2D semiconductors need to be solved urgently. Sb3+/Bi3+-based inorganic lead-free 2D Cs3(M3+)2X9 perovskites (M = Sb3+, Bi3+; X = Cl-, Br-, I-) are promising candidates to replace the toxic 2D hLHP. The contact properties of Cs3Sb2Cl9 with 2D metals are studied in this work to achieve tunable Schottky barrier heights (SBH). Density functional theory calculations reveal a weak FLP factor of 0.91 in the studied junctions, which is beneficial for improving the carrier injection efficiency through electrode design. Calculations of tunneling properties indicate that a Cd3C2 electrode tends to achieve low SBH and high tunneling probability, while a VS2 (H) electrode tends to realize high SBH and low tunneling probability, suggesting that diverse applications of Cs3Sb2Cl9 can be achieved through electrode engineering.

Multi-Group Polymer Coating on Zn Anode for High Overall Conversion Efficiency Photorechargeable Zinc-Ion Batteries.

The solar-driven photorechargeable zinc-ion batteries have emerged as a promising power solution for smart electronic devices and equipment. However, the subpar cyclic stability of the Zn anode remains a significant impediment to their practical application. Herein, poly(diethynylbenzene-1,3,5-triimine-2,4,6-trione) (PDPTT) was designed as a functional polymer coating of Zn. Theoretical calculations demonstrate that the PDPTT coating not only significantly homogenizes the electric field distribution on the Zn surface, but also promotes the ion-accessible surface of Zn. With multiple N and C=O groups exhibiting strong adsorption energies, this polymer coating reduces the nucleation overpotential of Zn, alters the diffusion pathway of Zn2+ at the anode interface, and decreases the corrosion current and hydrogen evolution current. Leveraging these advantages, Zn-PDPTT//Zn-PDPTT exhibits an exceptionally long cycling time (≥4300 h, 1 mA cm-2). Zn-PDPTT//AC zinc-ion hybrid capacitors can withstand 50,000 cycles at 5 A/g. Zn-PDPTT//NVO zinc-ion battery exhibits a faster charge storage rate, higher capacity, and excellent cycling stability. Coupling Zn-PDPTT//NVO with high-performance perovskite solar cells results in a 13.12 % overall conversion efficiency for the photorechargeable zinc-ion battery, showcasing significant value in advancing the efficiency and upgrading conversion of renewable energy utilization.

Interlamellar-Spacing Engineering of Stable and Toxicity-Reduced 2D Perovskite Single Crystal for High-Resolution X-ray Imaging.

Two-dimensional (2D) lead halide perovskites are excellent candidates for X-ray detection due to their high resistivity, high ion migration barrier, and large X-ray absorption coefficients. However, the high toxicity and long interlamellar distance of the 2D perovskites limit their wide application in high sensitivity X-ray detection. Herein, we demonstrate stable and toxicity-reduced 2D perovskite single crystals (SCs) realized by interlamellar-spacing engineering via a distortion self-balancing strategy. The engineered low-toxicity 2D SC detectors achieve high stability, large mobility-lifetime product, and therefore high-performance X-ray detection. Specifically, the detectors exhibit a record high sensitivity of 13488 µC Gy1- cm-2, a low detection limit of 8.23 nGy s-1, as well as a high spatial resolution of 8.56 lp mm-1 in X-ray imaging, all of which are far better than those of the high-toxicity 2D lead-based perovskite detectors. These advances provide a new technical solution for the low-cost fabrication of low-toxicity, scalable X-ray detectors.

Flexible Aqueous Supercapacitors for Long Cycle-Life Using Electrode with Multiple Active C═S Sites.

Even though a few organic materials have attracted considerable attention for energy storage applications, their dissolution in the electrolyte during the charging-discharging processes presents a formidable challenge to their long-term performance. In this work, according to the principle of like dissolves like, non-polar trithiocyanuric acid (TCA) can effectively inhibit dissolution in an aqueous electrolyte, hence prolonging the cycle life. Moreover, theoretical calculations suggest that TCA lowers lowest unoccupied molecular orbital (LUMO) energy level, thereby promoting reaction kinetics. The CV curves of TCA maintain a rectangular structure even at a high scan rate of 1000 mV s‒1 and exhibit a remarkable capacitance retention rate of 93.1% after 50,000 cycles. Asymmetric flexible supercapacitors utilizing the TCA exhibit an impressive energy density. Moreover, they maintain 94.2% of their capacitance after undergoing 80,000 cycles. Their integration with perovskite solar cells to facilitate the rapid storage of photogenerated charges enables efficient solar energy utilization, providing a practical solution for capturing and storing renewable energy.

Enhancing Performance and Stability of Perovskite Solar Cells with a Novel Formamidine Group Additive.

Perovskite materials, particularly FAPbI3, have emerged as promising candidates for solar energy conversion applications. However, these materials are plagued by well-known defects and suboptimal film quality. Enhancing crystallinity and minimizing defect density are therefore essential steps in the development of high-performance perovskite solar cells. In this study, 1H-Pyrazole-1-carboximidamide hydrochloride (PCH) is introduced into FAPbI3 perovskite films. The molecular structure of PCH features a pyrazole ring bonded to formamidine (FA). The FA moiety of PCH facilitated the incorporation of this additive into the film lattice, while the negatively charged pyrazole ring effectively passivated positively charged iodine vacancies. The presence of PCH led to the fabrication of an FAPbI3 device with improved crystallinity, a smoother surface, and reduced defect density, resulting in enhanced Voc and fill factor. A record power conversion efficiency of 24.62% is achieved, along with exceptional stability under prolonged air exposure and thermal stress. The findings highlight the efficacy of PCH as a novel additive for the development of high-performance perovskite solar cells.

Designed Additive to Regulated Crystallization for High Performance Perovskite Solar Cell.

It is a crucial role for enhancing the power conversion efficiency (PCE) of perovskite solar cells (PSCs) to prepare high-quality perovskite films, which can be achieved by delaying the crystallization of perovskite film. Hence, we designed difluoroacetic anhydride (DFA) as an additive to regulating crystallization process thus reducing defect formation during perovskite film formation. It was found DFA reacts with DMSO by forming two molecules, difluoroacetate thioether ester (DTE) and difluoroacetic acid (DA). The strong bonding DTE⋅PbI2 and DA⋅PbI2 retard perovskite crystallization process for high-quality film formation, which was monitored through in situ UV/Vis and PL tests. By using DFA additives, we prepared perovskite films with high-quality and low defects. Finally, a champion PCE of 25.28 % was achieved with excellent environmental stability, which retained 95.75 % of the initial PCE after 1152 h at 25 °C under 25 % RH.

Lattice Mismatch at the Heterojunction of Perovskite Solar Cells.

Lattice mismatch significantly influences microscopic transport in semiconducting devices, affecting interfacial charge behavior and device efficacy. This atomic-level disordering, often overlooked in previous research, is crucial for device efficiency and lifetime. Recent studies have highlighted emerging challenges related to lattice mismatch in perovskite solar cells, especially at heterojunctions, revealing issues like severe tensile stress, increased ion migration, and reduced carrier mobility. This review systematically discusses the effects of lattice mismatch on strain, material stability, and carrier dynamics. It also includes detailed characterizations of these phenomena and summarizes current strategies including epitaxial growth and buffer layer, as well as explores future solutions to mitigate mismatch-induced issues. We also provide the challenges and prospects for lattice mismatch, aiming to enhance the efficiency and stability of perovskite solar cells, and contribute to renewable energy technology advancements.

2D Hybrid Perovskites: From Static and Dynamic Structures to Potential Applications.

2D perovskites have received great attention recently due to their structural tunability and environmental stability, making them highly promising candidates for various applications by breaking property bottlenecks that affect established materials. However, in 2D perovskites, the complicated interplay between organic spacers and inorganic slabs makes structural analysis challenging to interpret. A deeper understanding of the structure-property relationship in these systems is urgently needed to enable high-performance tunable optoelectronic devices. Herein, this study examines how structural changes, from constant lattice distortion and variable structural evolution, modeled with both static and dynamic structural descriptors, affect macroscopic properties and ultimately device performance. The effect of chemical composition, crystallographic inhomogeneity, and mechanical-stress-induced static structural changes and corresponding electronic band variations is reported. In addition, the structure dynamics are described from the viewpoint of anharmonic vibrations, which impact electron-phonon coupling and the carriers' dynamic processes. Correlated carrier-matter interactions, known as polarons and acting on fine electronic structures, are then discussed. Finally, reliable guidelines to facilitate design to exploit structural features and rationally achieve breakthroughs in 2D perovskite applications are proposed. This review provides a global structural landscape of 2D perovskites, expected to promote the prosperity of these materials in emerging device applications.

Implementation of a Multi-Functional-Group Strategy for Enhanced Performance of Perovskite Solar Cells through the Incorporation of 3-Amino-4-Phenylbutyric Acid Hydrochloride.

Reducing the defect density of perovskite films during the crystallization process is critical in preparing high-performance perovskite solar cells (PSCs). Here, a multi-functional molecule, 3-phenyl-4-aminobutyric acid hydrochloride (APH), with three functional groups including a benzene ring, ─NH3 + and ─COOH, is added into the perovskite precursor solution to improve perovskite crystallization and device performance. The benzene ring increases the hydrophobicity of perovskites, while ─NH3 + and ─COOH passivate defects related to I- and Pb2+, respectively. Consequently, the power conversion efficiency (PCE) of the optimal device increased to 24.65%. Additionally, an effective area of 1 cm2 with a PCE of 22.45% is also prepared using APH as an additive. Furthermore, PSCs prepared with APH exhibit excellent stability by 87% initial PCE without encapsulation after exposure at room temperature under 25% humidity for 5000 h and retaining 70% of initial PCE after aging at 85 °C in an N2 environment for 864 h.

Surface Reconstruction for Efficient NiOx-Based Inverted Perovskite Solar Cells.

Functional agents are verified to efficiently enhance device performance of perovskite solar cells (PSCs) through surface engineering. However, the influence of intrinsic characteristics of molecules on final device performance is overlooked. Here, a surface reconstruction strategy is developed to enhance the efficiency of inverted PSCs by mitigating the adverse effects of lead chelation (LC) molecules. Bathocuproine (BCP) is chosen as the representative of LC molecules for its easy accessibility and outstanding optoelectronic properties. During this strategy, BCP molecules on perovskite surface are first dissolved in solvents and then captured specially by undercoordinated Pb2+ ions, preventing adverse n-type doping by the molecules themselves. In this case, the BCP molecule exhibits outstanding passivation effect on perovskite surface, which leads to an obviously increased open-circuit voltage (VOC). Therefore, a record power conversion efficiency of 25.64% for NiOx-based inverted PSCs is achieved, maintaining over 80% of initial efficiency after exposure to ambient condition for ≈1500 h.