Search

Perovskite solar cells (PSCs) have experienced exceptional development in recent years, due to their outstanding photoelectronic properties and low‐cost solution processing. Many state‐of‐the‐art PSC designs have been effectively demonstrated using a stacked 3D perovskite/2D perovskite heterostructure, yet limitations arise due to the low conductivity of the 2D perovskite, the hidden buried interface of 3D perovskite, and halide ion migration within 3D/2D PSC device under operational bias. Here, these limitations are overcome by developing a novel and universal post‐synthetic metal (Zn2+) doping strategy and realizing 3D/2D PSCs with superior efficiency and stability. Informed by ab initio calculations and synchrotron fine structure experiments, it is revealed that the introduced zinc ions are energetically favored at interstitial crystal sites, subsequently hindering the migration of halide ions and producing a beneficial shift toward a more n‐type character in the buried 3D perovskite interface. Combined with extensive photophysical characterization, the Zn2+‐modified 3D/2D perovskite thin film is shown to strongly recover its photo‐carrier conductivity compared with the 3D/2D perovskite film, boosting the efficiency (22.90%) of PSCs while exhibiting improved humidity and operational stability. [ABSTRACT FROM AUTHOR]

The facile oxidation of Sn2+ to Sn4+ poses an inherent challenge that limits the efficiency and stability of tin‐lead mixed (Sn−Pb) perovskite solar cells (PSCs) and all‐perovskite tandem devices. In this work, we discover the sustainable redox reactions enabling self‐healing Sn−Pb perovskites, where their intractable oxidation degradation can be recovered to their original state under light soaking. Quantitative and operando spectroscopies are used to investigate the redox chemistry, revealing that metallic Pb0 from the photolysis of perovskite reacts with Sn4+ to regenerate Pb2+ and Sn2+ spontaneously. Given the sluggish redox reaction kinetics, V3+/V2+ ionic pair is designed as an effective redox shuttle to accelerate the recovery of Sn−Pb perovskites from oxidation. The target Sn−Pb PSCs enabled by V3+/V2+ ionic pair deliver an improved power conversion efficiency (PCE) of 21.22 % and excellent device lifespan, retaining nearly 90 % of its initial PCE after maximum power point tracking under light for 1,000 hours. [ABSTRACT FROM AUTHOR]

Formamidinium lead iodide quantum dots (QDs) show great potential for solar cell applications but suffer from restricted charge transfer due to the insulating nature of their ligand shell. Management of the surface properties and resultant energy band alignment is the key to efficient and stable QD solar cells. Herein, an advance in QD surface passivation by introducing tailored multifunctional ligands (glycocyamine (GLA)) to the FAPbI3 QD surface is demonstrated. The incorporation of GLA ligands can partly substitute the native long‐chain insulating ligands and effectively reduce the non‐radiative recombination loss induced by surface trap states. Notably, the introduction of GLA ligands beneficially shifts the band offsets of the QD films and generates a homojunction structure with a cascading energy band alignment in the QD layers, promoting favorable charge transport and boosting the device's performance. As a result, a record‐high power conversion efficiency (PCE) of 15.34% with improved open‐circuit voltage and fill factor is achieved. Moreover, the GLA‐assisted surface passivation boosts the device stability, in which over 80% and 75% of the original PCEs are maintained after storing the devices for 5500 h in ambient air and 768 h under continuous 1‐sun illumination, respectively. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have witnessed an unprecedentedly rapid development, especially in terms of power conversion efficiency (PCE). However, the solution‐processed perovskite films inevitably possess numerous crystallographic defects (e.g., halide vacancies), which has been shown to incur non‐radiative charge recombination and ion migration, thus limiting the enhancement of the PCE and stability of PSCs. Here, a novel dual metal (i.e., divalent and monovalent metal ions) modification strategy is reported for simultaneously reducing the defects, immobilizing the halide anions, and preventing ion loss from perovskite during post‐annealing process. Accordingly, this strategy significantly reduces non‐radiative recombination, enhancing the PCE by ≈12% and mitigating the current density‐voltage (J–V) hysteresis effect in resultant devices compared to undoped counterparts. As a result, a champion PCE exceeding 22% and a high open‐circuit voltage (Voc) of 1.16 V is obtained for dual metal ions‐modified PSCs. The optimized devices also exhibit extended lifespan upon the dual metal treatment. The study provides a new defect engineering strategy toward more efficient and stable perovskite photovoltaics. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) of formamidinium lead triiodide (FAPbI3) perovskite hold great potential, outperforming their inorganic counterparts in terms of phase stability and carrier lifetime, for high‐performance solar cells. However, the highly dynamic nature of FAPbI3 QDs, which mainly originates from the proton exchange between oleic acid and oleylamine (OAm) surface ligands, is a key hurdle that impedes the fabrication of high‐efficiency solar cells. To tackle such an issue, here, protonated‐OAm in situ to strengthen the ligand binding at the surface of FAPbI3 QDs, which can effectively suppress the defect formation during QD synthesis and purification processes is selectively introduced. In addition, by forming a halide‐rich surface environment, the ligand density in a broader range for FAPbI3 QDs without compromising their structural integrity, which significantly improves their optoelectronic properties can be modulated. As a result, the power conversion efficiency of FAPbI3 QD solar cells (QDSCs) is enhanced from 7.4% to 13.8%, a record for FAPbI3 QDSCs. Furthermore, the suppressed proton exchange and reduced surface defects in FAPbI3 QDs also enhance the stability of QDSCs, which retain 80% of the initial efficiency upon exposure to ambient air for 3000 hours. [ABSTRACT FROM AUTHOR]

Simplified perovskite solar cells (PSCs) were fabricated with the perovskite layer sandwiched and encapsulated between carbon‐based electron transport layer (ETL) and counter electrode (CE) by a fully blade‐coated process. A self‐assembled monolayer of amphiphilic silane (AS) molecules on transparent conducting oxide (TCO) substrate appeals to the fullerene ETL deposition and preserves its integrity against the solvent damage. The AS serves as a "molecular glue" to strengthen the adhesion toughness at the TCO/ETL interface via robust chemical interaction and bonding, facilitating the interfacial charge extraction, increasing PCEs by 77 % and reducing hysteresis. A PCE of 18.64 % was achieved for the fully printed devices, one of the highest reported for carbon‐based PSCs. AS‐assisted interfacial linkage and carbon‐material‐assisted self‐encapsulation enhance the stability of the PSCs, which did not experience performance degradation when stored at ambient conditions for over 3000 h. [ABSTRACT FROM AUTHOR]

Core/shell structured metal halide perovskite nanocrystals (NCs) are emerging as a type of material with remarkable optical and electronic properties. Research into this field has been developing and expanding rapidly in recent years, with significant advances in the studies of the shell growth mechanism and in understanding of properties of these materials. Significant enhancement of both the stability and the optical performance of core/shell perovskite NCs are of particular importance for their applications in optoelectronic technologies. In this review, the recent advances in core/shell structured perovskite NCs are summarized. The band structures and configurations of core/shell perovskite NCs are elaborated, the shell classification and shell engineering approaches, such as perovskites and their derivative shells, semiconductor shell, oxide shell, polymer shell, etc. are reviewed, and the shell growth mechanisms are discussed. The prospective of these NCs in lighting and displays, solar cells, photodetectors, and other devices is discussed in the light of current knowledge, remaining challenges, and future opportunities. [ABSTRACT FROM AUTHOR]

We, for the first time, correlated the alkyl chain length of amine molecules with the defect passivation efficacy, either on the surfaces or at grain boundaries of perovskite films. Blade-coated perovskite solar cells with long-chain amine passivation achieved an efficiency of 21.5%, accompanied by a small voltage loss of 0.35 V. [ABSTRACT FROM AUTHOR]

Nanocrystal/polymer solid solar cells have the advantages of low-cost, simple process, and flexible manufacture. In this work, ternary solid solar cells based on FeS 2 and PbS nanocrystals exhibited photovoltaic conversion efficiency of 3.0% and 3.1%, respectively. As a kind of semiconductor with optical absorption in the visible and near-infrared regions, FeS 2 nanocrystals matched well with the solar radiation spectrum. Furthermore, PbS Nanocrystals could increase the number of electrons, due to its multiple exciton effect. Additionally, the FeS 2 nanocrystals solar cells showed high stability, with 83.3% of its initial efficiency remained after 15 weeks of exposure in air, and kept good stable performance at 20–80 °C. The photovoltaic conversion efficiency fluctuation magnitudes were also found to be smaller than quantum-dot sensitized solar cell under the same conditions. [ABSTRACT FROM AUTHOR]

A low-temperature method for the large-scale growth of ZnO thin films on flexible substrates was realized using a mist chemistry vapor deposition setup. We prepared and analyzed ZnO thin films grown on flexible PET/ITO in the temperatures range of 125-250 °C. The growth of ZnO crystallites was qualitatively investigated with respect to nucleation and substrate temperature. We observed a mixed phase in the ZnO thin films prepared at 125 and 150 °C. We conclude that the optimal substrate temperature for optimal ZnO thin films growth is between 150-200 °C. Our results show that the photovoltaic performance of an organic solar cell (OSC) is strongly dependent on both composition and morphology. To demonstrate its application on flexible organic optoelectronic devices, a large OSC with as-grown ZnO thin film as cathode buffer layer was successfully prepared. [ABSTRACT FROM AUTHOR]

A novel ultrasonic spray pyrolysis for high-quality ZnO films based on zinc-ammonia solution was achieved in air. To investigate the structural and optical properties as well as the performance of polymer solar cells (PSCs), ZnO films at different substrate temperatures and thicknesses were prepared. The performance of poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM) based PSC was found to be improved due to the ZnO films. The crystal structure and roughness of the ZnO films fabricated at different temperatures were found to affect the performance of PSCs. The optimized power conversion efficiency was found to be maximum for PSCs with ZnO films prepared at 200°C. The growth process of these ZnO films is very simple, cost-effective, and compatible for larger-scale PSC preparation. The precursor used for spray pyrolysis is environmentally friendly and helps to achieve ZnO film preparation at a relative low temperature. [ABSTRACT FROM AUTHOR]

The inverted polymer solar cell was prepared by self-made spray-coating system, and the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transport layer was studied. 220 nm poly-(3-hexylthiophene):[6,6]-phenylC61butyric-acid methyl-ester (P3HT:PCBM) and 40 nm PEDOT:PSS were deposited on ZnO thin film subsequently by solution spray coating. Different volume of isopropyl alcohol was introduced into PEDOT:PSS to decrease the contact angle and obtain the optimum Marangoni flow. The surface morphology and roughness of PEDOT:PSS films were characterized by atomic force microscopy with varied deposition temperature from 70°C to 160°C. The improvement of power conversion efficiency (PCE) was attributed to the enhancement of vertical phase separation in PEDOT:PSS film, which improved the charge transfer in the bulk cell. The highest PCE of spray-coated PSCs reached 2.80% after postannealing for 10 min. [ABSTRACT FROM AUTHOR]

Recent years have witnessed an incredibly high fever in metal halide perovskite materials due to their promising applications in a wide range of optoelectronic applications. The morphologies and optoelectronic properties of the perovskite layers play critical roles in affecting the optoelectronic performances. This review summarizes the recent advances in the fabrication of a variety of perovskite morphologies and their promising progress achieved in different optoelectronic applications, including solar cells, light‐emitting diodes, photodetectors, lasers, photocatalysis, X‐ray detectors/imagers, and luminescent solar concentrators. Several blossoming representatives, including 0D perovskite quantum dots, 1D perovskite nanowires, 2D perovskite nanosheets/nanoplatelets, and 3D textured perovskite assemblies (i.e., cuboid‐like, inverse opal‐like, coral‐like, or maze‐like morphologies, etc.), are highlighted to demonstrate their fascinating properties and outstanding capabilities for efficient optoelectronic applications. Finally, a perspective on the remaining challenges and future directions of fabricating unique perovskite morphologies for next‐generation high‐performance optoelectronic devices is provided. [ABSTRACT FROM AUTHOR]

This review highlights the recent advances of employing the perovskite crystals redissolution strategy in perovskite photovoltaics, with particular emphasis on comparing different methodologies for synthesizing perovskites, elucidating the distinct solution chemistry, analyzing the cost advantages, as well as underlining the desirable thin-film superiority with improved quality and enhanced optoelectronic properties. [Display omitted] High-efficiency perovskite solar cells (PSCs) normally rely on costly, high purity (>99.99%), air-sensitive raw materials that vary batch-to-batch. The perovskite films and devices derived from conventional raw materials mixture method suffer from inferior reproducibility of optoelectronic properties and performance, as well as discounted promise towards low-cost scalable manufacturing. Distinguished from the direct mixing of raw materials, the preparation of perovskite films with precursors made by the redissolution of perovskite crystals holds the promise to make PSCs more affordable, reproducible, efficient and stable. The resultant perovskite films inherit the exceptional characteristics of the parent perovskite crystals, such as high crystallinity, high purity, accurate stoichiometric ratio, and low trap-state density, as well as good ambient and phase stability. Herein, we summarize recent progress on the employment of the perovskite crystals redissolution strategy for achieving low-cost, efficient perovskite-based solar-to-electricity conversion, which will help both popularize the redissolution strategy and reveal unprecedented advantages gained by its adoption. [ABSTRACT FROM AUTHOR]