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Organic–inorganic halide perovskite (OIHP) spintronics has become a promising research field, as it provides a new precisely manipulable degree of freedom. Recently, by utilizing the spin Seebeck effect and inverse spin-Hall effect measurements, we have discovered substantial magnon injection and transport in Pt/OIHP/Y3Fe5O12nonlocalized structure. In theory, hyperfine interaction (HFI) is considered to have an important role in the magnon transport of OIHP, but there is no clear experimental evidence reported so far. We report increased spin Seebeck coefficient and lengthened magnon diffusion length in deuterated- (D-) OIHP films that have weaker HFI strength compared with protonated- (H-) OIHP. Consequently, D-MAPbBr3film, as a non-ferromagnetic spacer, achieves long magnon diffusion length at room temperature (close to 120.3 nm). Our finding provides valuable insights into understanding magnon transport in OIHP films and paves the way for the use of OIHPs in multifunctional applications.

The interface is of paramount importance in heterostructures, as it can be considered as a device in accordance with Kroemer’s dictum. In perovskite solar cells (PSCs), optimizing the interface between the perovskite layer and the hole transport layer is known to be an effective method for enhancing PSC device performance. Herein, a metal ruthenium complex coded as C101 is introduced to the perovskite (CsPbI2Br)/hole transport layer (PTAA) interface as a “charge driven motor” to selectively extract holes from CsPbI2Br and then transfer them to PTAA, minimizing the voltage loss in PSCs. More significantly, the introduction of C101 layer effectively passivates the surface of CsPbI2Br film and reduces the defect density of CsPbI2Br film due to the covalent bond between the CsPbI2Br and the–C=O group in C101. The photovoltaic performance of CsPbI2Br PSCs is enhanced by 23.60% upon the introduction of C101 interfacial layer, with the champion CsPbI2Br PSC exhibiting a power conversion efficiency of 14.96% in a reverse scan, a short-circuit current of 15.84 mA·cm−2, an open-circuit voltage of 1.15 V, and a fill factor of 82.03%. Additionally, the introduction of C101 simultaneously enhances the humidity tolerance of CsPbI2Br PSCs.

We review the recent advances in utilizing seed-assisted method to grow high-quality perovskite films for efficient solar cells. Different seeding materials and methods are carefully discussed.

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–1cm–2under an electric field of 44.44 V mm–1and a low detection limit of 28.64 nGyairs–1under an electric field of 22.22 V mm–1. These values exceed the 323.86 μC Gyair–1cm–2and 40.52 nGyairs–1of the pristine perovskite thick film measured under the same conditions. The optimized thick film also shows promising working stability and X-ray imaging capability.

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–1in 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.

Halide perovskites are emerging as promising materials for X-ray detection owing to their compatibility with flexible fabrication, cost-effective solution processing, and exceptional carrier transport behaviors. However, the challenge of removing lead from high-performing perovskites, crucial for wearable electronics, while retaining their superior performance, persists. Here, we present for the first time a highly sensitive and robust flexible X-ray detector utilizing a biocompatible, metal-free perovskite, MDABCO-NH4I3(MDABCO = methyl-N′-diazabicyclo[2.2.2]octonium). This wearable X-ray detector, based on a MDABCO-NH4I3thick membrane, exhibits remarkable properties including a large resistivity of 1.13 × 1011Ω cm, a high mobility-lifetime product (μ–τ) of 1.64 × 10–4cm2V–1, and spin Seebeck effect coefficient of 1.9 nV K–1. We achieve a high sensitivity of 6521.6 ± 700 μC Gyair–1cm–2and a low detection limit of 77 nGyairs–1, ranking among the highest for biocompatible X-ray detectors. Additionally, the device exhibits effective X-ray imaging at a low dose rate of 1.87 μGyairs–1, which is approximately one-third of the dose rate used in regular medical diagnostics. Crucially, both the MDABCO-NH4I3thick membrane and the device showcase excellent mechanical robustness. These attributes render the flexible MDABCO-NH4I3thick membranes highly competitive for next-generation, high-performance, wearable X-ray detection applications.

Oxygen vacancy-rich titania is a promising support for enhancing the hydrogen evolution reaction (HER). This work innovatively loaded Pt nanoparticles on oxygen vacancy-rich TiO2(Pt/Vo-TiO2) in situby using a photocatalytic device. The synthesis conditions are mild, do not require high temperatures and strong reducing agents, and can avoid the accumulation of platinum species. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectrometry (XAS) verified the synergistic effect of Pt species and oxygen vacancies on the progress of the reaction kinetics, where the Pt particles exposed by the in situsynthesis functioned as reaction sites in the electrocatalytic hydrogen evolution. Based on this, Pt/Vo-TiO2exhibits excellent electrocatalytic performance with an overpotential of only 56 mV at a current density of 10 mA cm–2and a Tafel slope of only 73.5 mV dec–1. This work provides a new strategy for designing highly efficient HER catalysts.

In metal halide perovskite solar cells the formation of a 2D/3D bulk heterostructure has a positive effect on device stability but can be detrimental to charge transport and power conversion efficiency (PCE). Herein, we report that amidino-based Dion-Jacobson 2D perovskite enables the creation of an efficient and stable FAPbI3-based 2D/3D heterostructure in perovskite solar cells. The 2D-perovskite-assisted nucleation/growth of 3D perovskites during film formation was found by using time-resolved optical diagnostics, which decrease concentrations of voids and bulk defects of perovskite films for efficient charge transport. The planar perovskite solar cells based on 2D/3D heterostructures achieved efficiencies of 24.9% and 22.3% on rigid and flexible substrates, respectively, which are the highest efficiencies among all 2D/3D composite solar cells. Improved stability was further demonstrated, with 97% of original efficiency retained for rigid solar cells without encapsulation after 1,000 h of storage under ambient conditions (RH 30%–40%) and 92% for flexible solar cells after 3,000 bending cycles.

Fabrication of high-efficiency organic solar cells (OSCs) using nonhalogen green solvents is highly desired for commercialization. However, the morphology control of a nonhalogen solvent-processed active layer remains challenging because of poor solubility of the commonly used photovoltaic materials in nonhalogen solvents. Herein, we propose a two-step heating strategy to optimize the morphology of a photovoltaic active layer based on a low-cost polymer donor X1 and a small-molecule acceptor (SMA) BTP-eC9 processed from a mixed nonhalogen solvent. First, heating the blend solution can robustly enhance the solubility of the SMA and thus processability of the blend, producing a uniform active layer. Second, further elevating the substrate temperature can shorten the film-formation time and tune the size of the polymer aggregates and SMA crystallites, to form bicontinuous networks in the active layer. As a result, this two-step heating strategy endows the film with improved charge generation, transport, and collection and thus a much higher device efficiency (ca. 4.6 times of that for the as-cast device) in comparison to those from nonoptimal solution and/or substrate temperatures. This work emphasizes the crucial role of regulating processing conditions in fabricating the nonhalogen solvent-processed high-efficiency OSCs.

Developing perovskite-based tandem solar cells (TSCs) is a promising technique to surpass the Shockley-Queisser limit set for single-junction solar cells. Encouragingly, all the perovskite-based TSCs, including perovskite/silicon, perovskite/perovskite, perovskite/copper indium gallium selenide and perovskite/organic tandems have demonstrated higher efficiency than the corresponding single-junction solar cells, showing great potential for further breakthroughs. In tandem devices, charge transport materials (CTMs) are vital components of perovskite sub-cells that directly determine the charge transportation and energy loss. Generally, high conductivity and transmittance, favorable energy-level alignment and chemical stability are crucial for CTMs for tandem applications. To date, various CTMs including conductive metallic oxides, organic molecules, polymers, fullerenes, and self-assembled materials have been extensively employed in highly efficient TSCs. In this review, we first summarize the recent progress of CTMs for different types of monolithic perovskite-based TSCs, in which the electrical and optical properties of CTMs and their influence on device performance are carefully discussed. Then we put forward the challenges and outlook for the further development of CTMs for tandem applications. This comprehensive review will provide effective guidance for device design for different perovskite-based TSCs.

For the exploration of stable lead-free perovskites for solar cell applications, we propose a series of Dion–Jacobson (DJ) double perovskites with the formula BDA2MIMIIIX8(BDA = 1,4-butanediamine) by substituting two Pb2+in BDAPbI4with an MI+(Na+, K+, Rb+, Cu+, Ag+, and Au+) and MIII3+(Bi3+, In3+, and Sb3+) pair. First-principles calculations demonstrated the thermal stabilities of all the proposed BDA2MIMIIIX8perovskites. The electronic properties of BDA2MIMIIIX8depend strongly on the choice of MI++ MIII3+and the structural archetype, and three out of 54 candidates with suitable solar band gaps and superior optoelectronic properties were selected for photovoltaic application. A highest theoretical maximal efficiency of over 31.6% is predicted for BDA2AuBiI8. The DJ-structure-induced interlayer interaction of apical I–I atoms is found to play a crucial role in promoting the optoelectronic performance of the selected candidates. This study provides a new concept for designing lead-free perovskites for efficient solar cells.

The additive strategy has emerged as an effective approach to improving the performance of perovskite solar cells (PSCs). Herein, a small acceptor-donor-acceptor type molecule indaceno[1,2-b:5,6-b′]dithiophene chloride (IDT-Cl) is designed and synthesized to advance both the efficiency and stability of FA0.85MA0.15PbI3PSCs. Within the IDT-Cl molecule, the S-group with high electron density promotes chemical bonding with the lead cations in the perovskite, resulting in enlarged grain size and smoother surface topography of the perovskite absorber. In addition, the undercoordinated lead ions in the perovskite layer may be passivated by the carbonyl group in the 5-chloroindolin-2-one unit, thereby reducing the number of nonradiative recombination centers. Meanwhile, the IDT-Cl adjusts the energy level mismatch between the perovskite and two adjacent carrier transport layers, leading to easy charge collection. By the multifunctional effect of the IDT-Cl molecule, the modified device yields a high power conversion efficiency (PCE) of 24.46%, 8.8% higher than that of the control PSC (22.48%). More importantly, the hydrophobic alkyl side-chain of the IDT-Cl molecule further ensures enhanced humidity stability of the perovskite film and environmental, thermal, and light stabilities of the PSC devices.

The use of non-halogenated solvents for the green manufacture of high-efficiency organic solar cells (OSCs) is important for their future application. However, the power conversion efficiency (PCE) of the non-halogenated solvent processed OSCs is generally lower than their halogenated counterpart due to the poor film microstructure caused by the solubility issue. Herein, we propose a halogen-free solvent system to optimize film microstructure of the photovoltaic blend based on the polymer donor D18 and small-molecule acceptor (SMA) L8-BO towards high-efficiency OSCs. The solvent system is consisted of a main solvent carbon disulfide and an additive paraxylene, where the former ensures the good solution-processability and promotes the solution aggregation of L8-BO, and the latter can finely control the phase-separation process by selectively dissolving the SMA. This solvent combination robustly produces a high-quality active layer, i.e., the bicontinuous networks of donor and acceptor with nano-sized phase-separation and strong π−π stacking. With the effective charge generation, transport and collection, the resulting device from the non-halogenated solvent system shows a high PCE of 17.50%, which is comparable to that of the device prepared from the halogenated solvent chloroform (ca. 17.11%). This article proposes a new strategy for the green fabrication of high-efficiency OSCs to accelerate their industrialization.

Even though the power conversion efficiency (PCE) of the perovskite solar cell has been increased to 25.7%, essentially all solvent systems implemented for the deposition of perovskites are toxic to the environment. In this study, a light modulation strategy is used to prepare perovskite from an absolutely green water-solvent-based precursor (Pb(NO3)2/H2O) system. The “light” effect significantly promotes the conversion kinetics and tailors the microstructure of lead halide, which will template the growth of perovskite. It is found that, when the light intensity reaches 1 Sun illumination, α-to-δ FAPbI3phase transition occurs. In the absence of light, metallic lead will be formed in perovskite. A unique iodide self-compensation effect is observed when the light intensity is optimized under 0.01 Sun illumination. The water-processed perovskite renders a record-high PCE of 23.74% and exhibits outstanding environmental stability. The feasibility of using water as the solvent paves an avenue for authentic green synthesis of perovskite materials.

Perovskite solar cells (PSCs) are undergoing rapid development and the power conversion efficiency reaches 25.7% which attracts increasing attention on their commercialization recently. In this review, we summarized the recent progress of PSCs based on device structures, perovskite-based tandem cells, large-area modules, stability, applications and industrialization. Last, the challenges and perspectives are discussed, aiming at providing a thrust for the commercialization of PSCs in the near future.

Solid-state microstructures of conjugated polymers are essential for charge transport in electronic devices. However, precisely modulating aggregation pathways of conjugated polymers in a controlled fashion is challenging. Herein, we report a sequential aggregation approach via selectively modulating side chain aggregation in solution state and backbone aggregation during film formation to increase H-aggregates and consequently enhance hole mobility of printed diketopyrrolopyrrole-based polymer (PDPP-TVT) film. The sequential aggregation is realized by introducing 1-bromonaphthalene additive into chloroform solvent. The structural evolution and assembly pathways of PDPP-TVT in initial solution and during printing were revealed using small-angle neutron scattering, cryogenic transmission electron microscopy, and time-resolved optical diagnostics. The results show that the poor interactions between PDPP-TVT side chains and BrN triggers side chain aggregation to form large H-aggregate nuclei in initial solution. The additive further selectively forces backbone aggregation on H-aggregate nuclei during printing with dynamics increasing from ca. 3 to >1000 s. Such prolonged growth window and selective growth of H-aggregates produce large fibers in printed film and therefore 3-fold increase in hole mobility. This work not only provides a promising route toward high-mobility printed conjugated polymer films but also reveals the important relationship between assembly pathways and film microstructure.

Organic-inorganic hybrid perovskites (OIHPs) have been touted as a superstar for photovoltaic applications. Recently, their importance in spintronics and magnonics came into the spotlight as superior characteristics were uncovered, namely, the Rashba-splitting effect, electronic spin properties, and spin-orbit coupling. However, until now, their magnon characteristics have not been studied. Herein, we demonstrate magnon injection into OIHP film from an adjacent ferromagnet at room temperature. By investigating the longitudinal spin Seebeck effect and the inverse spin-Hall effect, the magnon-transport behavior in OIHP is revealed. It is found that OIHPs not only have the longest-distance magnon transport compared with some known non-ferromagnetic insulators, but they also can be used as a spacer to prevent the magnetic proximity effect from contaminating magnon currents. Furthermore, both organic and inorganic ions in OIHP are discovered to play important roles in magnon properties. The present work paves a way for OIHPs to be used in magnonic applications.

2D Dion–Jacobson (DJ) perovskites have recently drawn much attention due to their superior charge transport and high environmental stability. Unfortunately, the issue of toxicity regarding the Pb element in perovskites has yet to be solved. Herein, we propose a new BDA2CuBiI8(1,4-butanediamine) 2D perovskite by substituting two Pb2+with the pair of Cu+and Bi3+to achieve Pb-free halide perovskites. The first-principles calculations demonstrated the thermodynamic and dynamic stabilities of 2D BDA2CuBiI8. Furthermore, the results indicate that this new material has a direct band gap of 1.58 eV suitable for solar cells with a theoretical maximal efficiency over 30% and allows direct transitions between band edges contrary to its bulk counterpart. The interlayer interaction of apical I–I is found to play a crucial role in determining the band edges. The findings indicate DJ structure type and double substitution together provide a new method for designing lead-free perovskites for efficient solar cells.

The design and development of low-cost and efficient photovoltaic materials remain a major challenge for the research and application of polymer solar cells (PSCs). Therefore, developing efficient photovoltaic polymers with simple structure and easy preparation has become an important research topic. Here we report a facilely synthesized electron-donating polymer X1with a simple chemical structure, which is composed of carboxylated benzo[1,2-b:4,5-b′]dithiophene (BDT) and thiophene unit. The carboxylate substituents on the BDT unit endowed the polymer with appropriate solubility, low-lying highest occupied molecular orbital (HOMO) energy level, and superior absorption. The PSCs based on X1as donor showed a high power conversion efficiency of 16.6%, with a remarkable short-circuit current density of 27.07 mA cm−2. These results demonstrated that X1is a highly promising candidate for low-cost and efficient PSCs. Furthermore, this study revealed the potential of carboxylated BDT as an effective building block in the research and development of high-performance photovoltaic materials.

It is arduous to prepare thin charge transport layers (CTLs) of only a few nanometers in thickness for meter-sized products, particularly for commonly used solution processes. Thus, it is desirable to take advantages of both solution-processed perovskites and vacuum-deposited CTLs. Herein, a surface redox engineering (SRE) is proposed for vacuum-deposited NiOxto make it match with the slot-die-coated perovskite films. Not only does it eliminate the de-wetting problem of perovskite ink, but it also imparts enhanced electronic properties at buried interfaces. Consequently, high-performance PSCs are achieved with amazing stability and outstanding power conversion efficiencies of 23.4% and 21.3% for rigid and flexible devices, respectively. Furthermore, perovskite submodules of area 156 × 156 mm2are successfully assembled with a remarkable PCE of 18.6% along with excellent stability. The SRE provides a strategy to use the advantages of both vacuum-fabricated CTLs with wet-processed perovskites for the development of large-area perovskite modules.

Meticulous engineering of the buried interface between the TiO2electron-transport layer and the CsPbI3-xBrxperovskite is crucial for interfacial charge transport and perovskite crystallization, thereby minimizing energy losses and achieving highly efficient and stable inorganic perovskite solar cells (PSCs). Herein, a functional molecular bridge is deliberately designed by integrating 3,4-thiophene dicarboxylic acid (TDDA) between the CsPbI3-xBrxperovskite and TiO2layer. It is demonstrated that the TDDA molecule exhibits a higher affinity towards the TiO2surface, forming tetradentate chelation through two CO···Ti bonds and two C-O-H···O bonds. Subsequently, it establishes a connection with perovskite via thiophene S-Pb interaction, thus creating an oriented molecular bridge at the buried interface. This effectively enhances charge extraction, passivates bilateral interfacial defects, alleviates lattice strain, and improves perovskite crystallization. Consequently, the combination of these advantageous characteristics results in a power conversion efficiency (PCE) of 22.04 % for a target CsPbI3-xBrxdevice with an active area of 0.09 cm2. Importantly, when scaled up to larger-area devices with an active area of 1.0 cm2, an remarkable PCE of 18.29 % was achieved. Furthermore, the stabilities of both perovskite films and corresponding PSCs were significantly enhanced through this molecular bridge strategy.

The burgeoning field of perovskite solar cells (PSCs) has achieved significant advancements, rivaling traditional photovoltaic technologies. However, efficient, and stable charge collection remains a critical hurdle for commercial deployment. This review aims to provide a comprehensive overview of various charge collection materials and their implications in perovskite photovoltaics. We assess state-of-the-art materials like indium tin oxide (ITO), conductive polymer, metal-based thin film, carbon-based alternatives, and more, exploring their optical properties, mechanical flexibility, electrical conductivity, and associated fabrication costs. While ITO remains the most commonly used due to its high transparency and conductivity, its scarcity and high-cost limit its scalability. Metal-based electrodes offer excellent conductivity and are emerging as leaders in applications requiring mechanical flexibility, but their permeation and interaction within perovskites need to be overcome. Carbon- and polymer-based materials offer stability and low cost but often suffer from lower conductivity. Each material class presents its own set of challenges, which must be addressed for real-world applications. This review also delves into innovative solutions, aiming to overcome these challenges, concluding by discussing the future potential and the key areas of research to realize durable, efficient, and cost-effective perovskite photovoltaics.

Metal-halide perovskitoids with corner-, edge-, and face-sharing octahedra provide a fertile “playground” for structure modulation. With low defect density, low ion migration, and high intrinsic stability, two-dimensional (2D) perovskitoid single crystals are expected to be ideal materials for room-temperature semiconductor detectors (RTSDs) as high-energy radiation. However, there is no report yet on the use of 2D perovskitoid single crystals for X-ray detection, as well as on how the halide-modulated molecular assembly would affect their structure and properties. Herein, based on an amidino-based organic spacer, we successfully synthesized a novel family of centimeter-sized 2D perovskitoid single crystals, (3AP)PbX4(3AP = 3-amidinopyridine, X = Cl, Br, and I). This is the first time that centimeter-sized 2D perovskitoid single crystals are demonstrated for X-ray photoresponse. Detailed investigations reveal a unique crystal packing with corner-sharing and edge-sharing octahedra of inorganic frameworks and 3AP cations lying between adjacent inorganic layers in a parallel and antisymmetric manner. Changing the halide from I to Br and Cl results in greater Pb–X–Pb angles and stronger hydrogen bonding in perovskitoids and therefore consequently a better elastic recovery under stress, a more efficient charge transport in the inorganic layer, and a lower ionic migration. By varying halide substitution, an efficient X-ray photoresponse is achieved with a sensitivity up to 791.8 μC Gyair–1cm–2for (3AP)PbCl4and a low detection limit of 1.54 μGyairs–1. These results reveal that the large 2D perovskitoid single crystals provide a promising platform for high performance optoelectronics.

Metal halide perovskites serving as one of the most promising photovoltaic materials are gaining considerable attention worldwide. For achieving high performance as well as long-term stability of the perovskite solar cells (PSCs), a good quality of perovskite film featuring in smooth, pinhole-free morphology, full coverage over substrates, good heterojunction contacts, and stable photoactive phase is of great importance. During solution fabrication for perovskite films, intermediate phase, which refers to the state of precursor composition before final annealing, plays an essential role in determining the film quality, especially in the state-of-the-art PSCs. In this review, we summarize the research involving mechanism and applications of intermediate phase engineering (IPE) processes in various solution-processing technologies. The challenges of IPE are further discussed, and perspectives are provided for developing high-performance PSCs via IPE.

All-inorganic CsPbI3perovskites have great potential in tandem cells in combination with other photovoltaic devices. However, CsPbI3perovskite solar cells (PSCs) still face a huge challenge, resulting in a low power conversion efficiency (PCE) relative to organic–inorganic PSCs. In this work, we introduced tetrabutylammonium acetate (TBAAc) as a buffer layer between the SnO2electron-transport layer (ETL) and CsPbI3all-inorganic perovskite film interface for the first time. TBAAc not only improved the conductivity of SnO2ETL but also formed a 1D TBAPbI3layer between the SnO2ETL and the 3D CsPbI3all-inorganic perovskite film, thereby enhancing the stability and passivating the surface defects of the CsPbI3perovskite to fabricate high-efficiency carbon-counter electrode (CE)-based CsPbI3solar cells. We fabricated carbon-CE-based hole-transporting layer ( HTL)-free PSCs with an FTO/SnO2/TBAAc/CsPbI3/C structure. The open-circuit voltage (Voc), short circuit current density (Jsc), PCE, and fill factor of the champion CsPbI3PSCs simultaneously enhanced to 1.08 V, 17.48 mA/cm2, 12.79, and 67.8%, respectively. This PCE is currently one of the high efficiencies reported for the above planar-structured carbon-CE-based CsPbI3PSCs to date. Moreover, the optimized device exhibits excellent stability, which retained over 83% of its initial PCE after 350 h. This work provides a facile way of simultaneous optimization of the SnO2ETL and the CsPbI3perovskite layer to fabricate stable and high-efficiency carbon-CE-based CsPbI3PSCs.

Perovskite solar cells represent a promising third-generation photovoltaic technology with low fabrication cost and high power conversion efficiency. In light of the rapid development of perovskite materials and devices, a systematic survey on the latest advancements covering a broad range of related work is urgently needed. This review summarizes the recent major advances in the research of perovskite solar cells from a material science perspective. The discussed topics include the devices based on different type of perovskites (organic-inorganic hybrid, all-inorganic, and lead-free perovskite and perovskite quantum dots), the properties of perovskite defects, different type of charge transport materials (organic, polymeric, and inorganic hole transport materials and inorganic and organic electron transport materials), counter electrodes, and interfacial materials used to improve the efficiency and stability of devices. Most discussions focus on the key progresses reported within the recent five years. Meanwhile, the major issues limiting the production of perovskite solar cells and the prospects for the future development of related materials are discussed.

Tetrabutylammonium hexafluorophosphate (TP6) treatment can not only passivate the surface defects of perovskite films, but also improve the moiture stability of perovskite films and photovoltaic cells.

The efficient X-ray detector based on centimeter-sized lead-free molecular one-dimensional perovskite single-crystal [(CH3)3NH]MnCl3·2H2O shows a sensitivity of 295 µC Gyair−1 cm−2and a low detection limit of 0.90 μGyair s−1.

It is of the utmost importance to promote the charge transport and retard the heterojunction barrier in the functional layers and at their adjacent interfaces to pursuit excellent photovoltaic characteristics of the perovskite solar cells (PSCs). Here, room-temperature sputtered-SnO2films are introduced to modify FTO anode for improving carrier extraction and aligning energy band in the TiO2-based planar PSCs. For the SnO2-modified substrate with suitable sputtering duration, the following TiO2film exhibits smoother surface roughness, less surface defects, and lower the trap-assisted interfacial recombination than that directly on the FTO, further facilitating the growth of perovskite grain size and promoting the extraction efficiency of charge carriers. On the basis of the optimized SnO2(6 nm)/TiO2stack layer as electron transport layer (ETL), the PSC exhibits an outstanding power conversion efficiency of 21.45%, which is much better than that of the single TiO2-based device (19.68%). More importantly, the cell with the bilayer ETL shows a long-term stability against air, maintaining over 76% of its initial efficiency after 40 d. These achievements suggest that this study provides a feasible path to design energy level alignment and low temperature ETL for highly efficient and stable PSCs.

The as-obtained 6% CoOOH-TiO2photoelectrode manifests enhanced PEC performance owing to the fast carrier migration across TiO2to CoOOH. And the valence transition of surface amorphous CoOOH plays a dominating role in the PEC process.

Organic-inorganic halide perovskite solar cells (PSCs) have emerged as a paradigm-shifting technology in photovoltaics, offering a low-cost avenue for the high-efficiency conversion of solar energy into electricity. Recent studies underscore the crucial role of material choice and structural design with specific focus on interface architecture in dictating the device efficiency and degradation kinetics of these devices. This review examines the influence of interfaces on the performance of PSCs. It categorizes and scrutinizes four distinct interfaces: electrode/electron transport layer (ETL), ETL/perovskite, perovskite/hole transport layer (HTL), and HTL/electrode, delving into their respective contributions to device performance. Furthermore, it provides a comprehensive overview of interface engineering strategies in carrier transport layer-free structures and carbon-based frameworks, elucidating their impact on enhancing reliability. Finally, the review outlines prospective directions for interface engineering, poised to fortify the stability and efficiency of PSCs in the quest for sustainable and reliable solar energy solutions.

Not until recently have metal-free halide perovskites become recognized as novel candidates for ferroelectrics and X-ray detection. However, molecular self-assembly of these perovskites and its influence remain unexplored. Here, we prepare large high-quality DABCO-NH4X3(DABCO = N-N′-diazabicyclo[2.2.2]octonium, X = Cl, Br, I) single crystals and demonstrate the understandings of how halide-modulated molecular assembly affects their crystal packing, band nature, mechanical and electrical properties, and final optoelectronic performance. In this series, the 1D crystal packing and low carrier effective masses endow superior in-plane charge transport for the I-based crystal. As such, higher carrier mobility (110 versus ∼10–20 cm2V−1s−1) and longer charge diffusion length (∼90 versus ∼50 μm) are achieved in contrast to the Cl- and Br-based analogs. The excellent charge transport properties finally translate to highly efficient X-ray detection and imaging for the I-based crystal detector, with a sensitivity up to 567 μC Gyair−1cm−2and a well-defined “heart” X-ray image.

Two-dimensional perovskites with unique quantum well structures present superior photovoltaics/optoelectronics in application of perovskite solar cells, photo detectors and X-ray detectors.

Perovskites, a wonder catalyst for solar energy conversion, have been used in the photocatalytic, photoelectrocatalytic, and photovoltaic-electrocatalytic cells for solar hydrogen production.

Halide-composition engineering has been recognized as an effective means to stabilize formamidine (FA)-based perovskite (FAPbI3) in thin-film devices. However, the influence of a halide mixture on the lattice strain, trap density, carrier lifetime, and phase stability remains unclear. Herein, FAPbBrxI3–xsingle crystals (SCs) are grown as a model to study how halide composition would affect the inner strain and the optoelectronic properties. It is found that by gradually increasing the Br/I ratio from 0:1 to 1:0, the inner strain can be regulated. X-ray diffraction results show excellent phase stability of FAPbBrxI3–xSCs (stable in an ambient atmosphere over 1.5 years when x≥ 0.5) because of the released expansion stress in the cubic lattice. The relevant photodetector presents good performance with an on–off ratio exceeding 103, a dark current as low as 10–10A, a linear dynamic range (LDR) of 111 dB, detectivity of 4 × 1011Jones, and long-term photostability. The present work paves a path toward the design of high-quality devices based on composition-optimized FAPbBrxI3–xSCs with predictable optoelectronic properties.

Two-dimensional (2D) perovskites with excellent stability and optoelectronic properties have aroused great interest for use in perovskite solar cells (PSCs). To date, the power conversion efficiencies (PCEs) of state-of-the art 2D-PSCs are non-satisfactory because of higher recombination losses in 2D quantum wells. Here, based on a series of alkylic ammonium spacers (ethylamine to hexylamine) with different chain lengths, we present a strategy via the molecular van der Waals interaction to realize modified crystallization, phase distribution, and quantum-confined behaviors in Ruddlesden-Popper 2D perovskites (n = 4). With the optimal amylamine (AA) spacer, high-quality 2D perovskites featuring well-aligned phase alignments with fewer unfavorable n-value species and a reduced exciton binding energy have been realized, leading to sufficient charge transfers through different n-value components. The devices based on (AA)2MA3Pb4I13yield a champion PCE of 18.42%, showing an impressive open-circuit voltage of 1.25 V and a fill factor exceeding 0.80.

Synergistic modifying TiO2with a thin C60layer and replacing lithium-doped small molecule with an un-doped conjugated polymer leads to an increase of 69% in efficiency for bismuth-halide double perovskite based solar cells.

During PVSEC29, researchers gave profound discussions on the issues hindering the development of perovskite solar cells and the latest progresses in the field such as crystallization control, stability improvement, the removal of barriers at interfaces, lead-free perovskite, and the extension of response regions, which can further boost stability and PCE, and reduce toxicity.Image, graphical abstract

The neutral hydrogen evolution reaction (HER) is vital in the chemical industry, and its efficiency depends on the interior character of the catalyst. Herein, work function (WF) engineering is introduced via 3dmetal (Fe, Co, Ni, and Cu) doping for modulating the Fermi energy level of Mo2C. The defective energy level facilitates the free water molecule adsorption and, subsequently, promotes the neutral HER efficiency. Specifically, at a current density of 10 mA/cm2, Cu-Mo2C exhibits the best HER performance with an overpotential of 78 mV, followed by Ni-Mo2C, Co-Mo2C, Fe-Mo2C, and bare Mo2C with 90, 95, 100, and 173 mV, respectively, and the corresponding Tafel slope values are 40, 43, 42, 56, and 102 mV/dec. The modified WF>can also lead to an enhanced photocatalytic efficiency owing to the lowered Schottky barrier and excellent carrier transition across the electrocatalyst–solution interface. When coupling the metal-doped Mo2C samples with TiO2, enhanced photocatalytic neutral HER rates are obtained in comparison to the case with bare TiO2. Typically, the HER rates are 521, 404, 275, 224, 147, and 112 μmol/h for Cu, Ni, Co, Fe, bare Mo2C, and bare TiO2, respectively. Time-resolved photoluminescence spectroscopy (TRPS) and ultrafast transient absorption (TA) measurements are carried out to confirm the recombination and migration of the photogenerated carriers. The fitted τ values from the TRPS curves are 22.6, 20.5, 10.1, 4.7, 4.0, 2.5, and 1.9 ns for TiO2, TiO2-Mo2C, TiO2-Fe-Mo2C, TiO2-Fe-Mo2C, TiO2-Fe-Mo2C, TiO2-Fe-Mo2C, and TiO2-Pt, respectively. Additionally, the fitted τ values from the TA results are 31, 73, and 105 ps for the TiO2-Mo2C, TiO2-Cu-Mo2C, and TiO2-Pt samples, respectively. This work provides in-depth insights into the WFmodulation of an electrocatalyst for improving the HER performance.

The optoelectronic properties of all-inorganic perovskite solar cells are greatly affected by the quality characteristics of films, such as the defect concentration, crystal growth orientation, crystallinity, and morphology. In this study, a PbI2-(DMSO)2complex is adopted to partially replace PbI2as the lead source in the preparation of perovskite precursor solutions. Due to the rapid dispersion of the PbI2-(DMSO)2complex in a solvent, raw materials can rapidly react to form perovskite colloids with a narrow size distribution. Such uniform colloidal particles are found to be beneficial for achieving films with improved quality and highly orientated growth along the [001] direction. The optimized film exhibits a clearly improved crystallinity and a decrease in defect concentration from 4.29 × 1015cm–3to 3.20 × 1015cm–3. The device based on the obtained all-inorganic CsPbI2.8Br0.2perovskite finally achieves an increase in photovoltaic power conversion efficiency from 10.5 to 14.15%. In addition, the environmental stability of the device also benefits from the improved film quality. After 480 h of storage in air, the device can still maintain nearly 80% of its initial performance.

Interface engineering has been recognized as a very effective method to simultaneously improve both efficiency and stability in perovskite solar cells (PSCs). In this work, we report using an excellent small molecular material tetraphenyldibenzoperiflanthene (DBP) to modify the perovskite/Spiro-OMeTAD interface to achieve significantly improved solar cell performance. It is found that the ultrathin DBP interlayer accelerates hole transfer across the FAxMA1–xPbInBr3–n/Spiro-OMeTAD interface and effectively reduces the nonradiative recombination. The Kelvin probe force microscopy and energy band analyses reveal that the DBP modification helps build better matched energy level alignment and smaller energy loss for more fluent hole transport. Consequently, the DBP-treated PSCs achieve an enhanced open-circuit voltage as high as 1.184 V and fill factor as high as 78.2% as well as the negligible hysteresis. The champion PSC made with DBP gives a PCE of 21.49%, significantly increased compared to 19.68% from the reference cell without the modification. Moreover, DBP also serves as a water-resistant protection for improved moisture stability. The PCE of the DBP-treated cells without encapsulation remains more than 84% of its initial efficiency, which is significantly higher than that of the reference PSCs (65%) after 20 days of storage under an air environment with 50–65% humidity. This study provides an effective interface modification material to address notorious stability problems in Spiro-OMeTAD-based PSCs.

Ion migration in perovskite materials accelerates its decomposition—deteriorating device performance, causing baseline drift, and lowering imaging resolution. In particular, in X-ray detectors, the effect of ion migration is more obvious under the necessary high working bias. Here, we report an effective strategy to grow superior inch-sized, high-quality, zero-dimensional (0D)-structured, lead-free (CH3NH3)3Bi2I9perovskite single crystals. These crystals have significantly lower ion migration, reduced dark current, and better environmental stability compared with other perovskites, enabling us to fabricate a type of 0D-structured perovskite X-ray detector. The X-ray detector shows high sensitivity of 1,947 μC Gyair−1cm−2, low detection limit of 83 nGyairs−1, short response time of 23.3 ms, the lowest baseline drift of 5.0 × 10−10nA cm−1s−1V−1, and the best long-term stability among all perovskites reported. The combination of large crystal size and excellent X-ray response allows us to fabricate the first 0D-structured perovskite X-ray imaging system.

Improving the quality of the perovskite active layer is crucial to obtaining high performance perovskite solar cells (PSCs). In this work, by introducing formic acid into the formamidinium lead iodide (FAPbI3) precursor solution, we managed to achieve reduced colloidal size in the solution, leading to more uniform deposition of FAPbI3film with lower trap state density and higher carrier mobility. The solar cells based on the FAPbI3absorber layer modified with formic acid show significantly better photovoltaic performance than that on the reference FAPbI3film without formic acid. The device performance shows a close correlation with the colloidal size. Within the range studied from 6.7 to 1.0 nm, the smaller the colloidal size is, the higher the solar cell efficiency. More specifically, the cell efficiency is improved from 17.82% for the control cell without formic acid to 19.81% when 0.764 M formic acid was used. Formic acid has also been added into a CH3NH3PbI3(MAPbI3) precursor solution, which exhibits a similar effect on the resulting MAPbI3films and solar cells, with efficiency improved from 16.07% to 17.00%.

Recently, novel inorganic two-dimensional (2D) Cs2PbI2Cl2and Cs2SnI2Cl2perovskites were reported, exhibiting excellent stability and superior optoelectronic properties. Because it has been suggested that perovskites based on light elements such as Cl or Sn would display high charge carrier mobility, 2D Cs2PbI2Cl2and Cs2SnI2Cl2are considered promising 2D materials with high carrier mobility because of the in-plane Pb–Cl and Sn–Cl framework. Here, we present a detailed theoretical investigation of the optoelectronic properties of newly fabricated 2D Cs2PbI2Cl2and Cs2SnI2Cl2and predict rather high, layer-dependent in-plane electron- and hole-dominated carrier mobilities for 2D Cs2PbI2Cl2and Cs2SnI2Cl2, respectively, based on deformation potential theory. The predicted hole mobility for trilayer Cs2SnI2Cl2(as high as ∼1.39 × 104cm2V–1s–1) and electron mobility for bilayer Cs2PbI2Cl2(as high as ∼9.39 × 103cm2V–1s–1) are much higher than those of the known halide perovskites and are comparable to those of black phosphorus. Additionally, the wide and direct band gaps, small effective masses, and low exciton binding energies of 2D Cs2PbI2Cl2and Cs2SnI2Cl2ensure their potentials as promising candidates for future electronics.

All-inorganic halide perovskites hold promise for emerging thin-film photovoltaics due to their excellent thermal stability. Unfortunately, it has been challenging to achieve high-quality films over large areas using scalable methods under realistic ambient conditions. Herein, we investigated the coupling between the fluid dynamics and the structural evolution during controlled film formation for ambient scalable fabrication of CsPbI2Br perovskite films using blade coating. We simultaneously overcame the negative influences of moisture attack and the Bénard-Marangoni instability in the drying ink and achieved an ideal sequential crystallization with changing halide composition during the film formation. As a result, we produced highly crystalline, uniform, and pinhole-free CsPbI2Br films with superior photophysical and transport properties. High-performance solar cells are fabricated to achieve power conversion efficiencies (PCEs) of 14.7% for small-aperture-area (0.03 cm2) devices and 12.5% for the large-aperture-area (1.0 cm2) ones, the highest PCE reported to date for large-area all-inorganic perovskite solar cells.

Two dimensional halide perovskites are emerging as attractive electroluminescent materials for developing high-performance light-emitting devices owing to their unique structures and/or superior optoelectronic properties. This review begins with an introduction to the working principles of and the key figures for evaluating the performance of LEDs. Secondly, the structure and optoelectronic properties of two dimensional perovskites are summarized and discussed. Their advantages in LED application over their 3D counterparts are systematically analyzed. Following the theoretically discussion, the progresses on the preparation of two dimensional perovskite materials as well as their performances in LEDs have been summarized. At last, several challenges and prospects are presented for achieving high performance 2D perovskite-based LEDs.

In spite of rapid progress in cesium lead halide (CsPbX3) perovskites solar cells (PSCs), their power conversion efficiencies (PCEs) achieved to date leave much space for further improvement, principally as a result of their large energy losses (Eloss). Herein, after incorporating 5% of Br ions into the CsPbI3film as the mixed-halide CsPbI2.85Br0.15-absorber layer, the optimized PSCs obtain a record reverse scan PCE of 17.17% and stabilized PCE of 16.83% with lower Elossof 0.58 eV. A record PCE of 12.28 and 13.14% are also achieved for large areas (1 cm2) and flexible substrates, respectively. More importantly, the optimized devices exhibit excellent thermal and compositional stability. Further characterizations have proved the much enhanced PCE and stability original from the Br induced suppressing bulk trap-assisted nonradiative recombination and lattice strain relaxation.

The two-dimensional (2D) layered organic-inorganic hybrid perovskites have demonstrated better performance in applications than their 3D counterparts due to their promising stability and excellent optoelectronic properties. In particular, the 2D perovskites show even better performance for certain optoelectronic devices, especially the ones fabricated on (001) plane. Unfortunately, these advantageous characteristics cannot be easily extracted from the randomly oriented microcrystalline films. Herein, we developed a surface-tension-controlled crystallization method to prepare large 2D (C6H5C2H4NH3)2PbI4((PEA)2PbI4) perovskite single crystals (PSCs). Using this technique, we have harvested some inch-sized 2D (PEA)2PbI4PSCs, with the largest one reaching 36 mm in length, resulting in extraordinary device performance. More specifically, the photodetectors fabricated on the (001) plane exhibit responsivity as high as 139.6 A W−1, external quantum efficiency 37,719.6%, detectivity 1.89 × 1015cm Hz1/2W−1, and response speed as fast as τrise = 21 μs and τdecay = 37 μs.

All-inorganic Br-rich perovskite photovoltaics with excellent stability have gained ever-increasing attention despite their slightly lower efficiency. Nowadays, trace heteroatom substitution has become a plausible approach to optimize perovskite properties as well as device performance. However, the substitution is limited by the Goldschmidt tolerance factor (t, 0.8 < t < 1.0), leading to the situation that the alternative deviating from the Goldschmidt rule is always overlooked, let alone utilized to enhance performance. Given this, Ba(II) is partially substituted for Pb(II) in CsPbIBr2to investigate how the dopants-induced deviation from the Goldschmidt rule would affect perovskite property. Intriguingly, the result verifies that Ba(II) enables increased the grain size and enhances the crystallinity of CsPbIBr2. As such, the trap state density is reduced and the non-radiative recombination in the perovskite is suppressed. These advantages bring about an increase of the power conversion efficiency (PCE) of Ba(II)-doped devices to 10.51%, outperforming that (8.4%) of the pristine counterpart. In addition, the perovskite stability is immune to Ba(II) substitution, even though it inflates the perovskite crystal lattice. These findings indicate that the perovskite films are tolerant to homovalent heteroatoms with a larger radius, stimulating further development of perovskite substitution engineering.

Despite incredible success has been achieved for perovskite solar cells (PSCs) in pursuing high power conversion efficiency (PCE), their practical application is prevented by the low stability issues, especially an accelerating stability test at high temperature still needs to be demonstrated. Herein, we present an inverted mesoscopic PSCs with Zn2+doped CuGaO2(Zn:CuGaO2) as both the scaffold and hole transporting materials (HTM). Both theoretical and experimental results indicate that the carrier density and conductivity of CuGaO2is significantly improved via Zn2+doping, which is beneficial for the hole transfer. Moreover, the mesoporous structure combined with the well matched energy levels between Zn:CuGaO2and perovskite can effectively extract holes from perovskite, reduce charge transfer barrier, and depress the charge-carrier recombination. As a result, the champion device with Zn:CuGaO2as HTM gives a power conversion efficiency of 20.67% from reverse scan and a stabilized efficiency of 20.15%, which is among the best results for PSCs based on methylammonium-free, cesium-formamidinium (Cs-FA) double-cation perovskite and inorganic HTM. Moreover, PCE of the unencapsulated device retains over 85% after thermal annealing at 85 °C for 1000 h in a nitrogen atmosphere, demonstrating the superior thermal stability of the present PSCs with the metal doped inorganic HTM.