Chen Weijie

Herein, the chemistry of tin perovskite compounds for the fabrication of high‐efficiency nontoxic solar cells is described. The reaction mechanisms among the compounds and additives present in the Sn perovskite films are discussed to correlate with the device performance.

Lead (Pb)‐based perovskite solar cells (Pb‐PSCs) have been recorded with a fascinating power conversion efficiency (PCE) of 25.5%. However, the presence of toxic Pb in the perovskite absorber material hinders the commercial aspects of Pb‐PSCs as a promising and efficient new generation of solar cells. Fortunately, theoretical calculations have predicted that tin (Sn)‐based perovskite solar cells (Sn‐PSCs) could have superior performance comparable to the Pb‐PSCs. Recently, many approaches have been reported for developing efficient Sn‐PSCs but yet they have shown the best PCE of 13.24%. This low PCE compared to Pb‐PSCs might be because Sn‐PSCs have been approached in the same way as Pb‐PSCs. However, from a chemistry viewpoint, the understanding of Sn‐PSCs might be very different from that of Pb‐based ones. Herein, the fundamental knowledge of the chemistry and coordination chemistry of Sn^II compounds and their structural properties is described. Then, an insight is provided into understanding the recent trends of Sn perovskite formation using various Lewis base additives in the precursor solution and incorporation as a cation in the perovskite lattice. Finally, the influence of utilizing Lewis base additives on the device dynamics is discussed.

A small molecule of 18C6 is introduced into the perovskite precursor for elongating the antisolvent dripping window from 2 to 20 s, achieving a high‐quality and reproducible perovskite film.

Although perovskite solar cells (PSCs) have exhibited a high‐power conversion efficiency, the reproducibility of high‐quality perovskite films is still a big challenge for large‐scale flexible devices. One reason is the super narrow antisolvent dripping window, the other one is the difficulty in controlling the secondary phases. Herein, 18C6 is introduced into the perovskite precursor to achieve a high‐quality and reproducible large‐scale (7 × 7 cm²) flexible perovskite film by enlarging the antisolvent dripping window from 2 to 20 s, with an average efficiency of 13.33% (best 15.80%). Moreover, from the in situ grazing‐incidence wide‐angle X‐ray scattering result, the 2H phase perovskite is highly suppressed with the additive of 18C6. The generality of the approach is also demonstrated in other antisolvents such as ethyl acetate. This finding provides an innovative solution to the realization of repeatable, large‐scale solution fabrication of PSCs.

Realizing the commercial applications of non‐fullerene organic solar cells (NFOSCs) require a balanced of power conversion efficiency (PCE), production cost, and stability. However, because most high‐performance NFOSC devices contain air‐sensitive donor polymers that have low solubility in eco‐friendly solvents, their fabrication requires halogenated solvents and an inert atmosphere. Herein, an air‐processed inverted NFOSC device is developed using a relatively cost‐effective chlorine‐ and carboxylate‐functionalized bithiophene‐based donor polymer, P(F‐BiT)‐COOBOCl(out). When blended with IT‐4F, the resultant device yields a high PCE of 11.91%, with good shelf‐life stability and photostability under ambient conditions without encapsulation, and less performance degradation than most reported NFOSCs. Importantly, when the polymer blend is processed in air with an eco‐ friendly solvent, 1,2,4‐trimethylbenzene, the resultant device exhibits a reasonably high PCE of 10.60% (certified PCE: 10.467%) without encapsulation, which is the highest value reported to date for NFOSCs fabricated under such conditions. The potential of this high‐performance and eco‐friendly processable polymer is further demonstrated in the excellent PCE of 14.22% of a device with a P(F‐BiT)‐COOBOCl(out):Y6‐BO‐4Cl blend prepared in o‐xylene solvent. This study provides perspectives and opportunities for designing and developing efficient photoactive materials as a new strategy for the commercialization of NFOSCs.

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An ultrafast and scalable laser process is developed to anneal TiO₂ films for perovskite solar cells. This laser process allows processing stacked layers of substrates simultaneously with a uniform annealing area up to 15.2 cm² and achieves a production rate of over 43 cm² min⁻¹, which potentially opens a new route for scalable annealing of thin films.

A conventional annealing method to fabricate metal oxide films used for perovskite solar cells (PSCs) is a time‐consuming batch process. Herein, a near‐IR fiber laser process with a unique design of power ramping program and beam configuration is developed to achieve ultrafast and scalable processing of TiO₂ films for PSCs. Highly crystalline anatase TiO₂ films can be synthesized in only 18.5 s by the laser process with a peak annealing temperature up to 800–850 °C, compared with that of the furnace‐annealing at 500 °C for 30 min and an overall processing time of 3 h. Then, a unique capability of using this laser process is presented to anneal stacked layers of substrates coated with the TiO₂ films simultaneously, with a uniform annealing area up to 15.2 cm², thereby potentially achieving an in‐line production rate of over 43 cm² min⁻¹ (1 cm² in ≈1.4 s). Planar PSCs fabricated under a high relative humidity of 60–70% based on the TiO₂ films annealed under optimal laser conditions show enhanced photovoltaic performance than the furnace‐annealed samples. This laser process potentially opens a new avenue for scalable annealing and rapid production of thin films.

A facile and efficient strategy of gradient doping is adopted for optimizing inverted CsPbI₂Br‐based perovskite solar cells (PeSCs) using a bicationic iodine salt, namely BFBAI₂, as the dopant. The doped PeSCs exhibit significantly improved photovoltaic performance and stability, which is attributed to efficient defect passivation and enhanced electric field upon the gradient doped BFBAI₂.

Cesium‐based all‐inorganic perovskites (PVKs) are prized for their high thermal stability and wide bandgap suitable for the top layer of tandem solar cells. To further boost the photovoltaic performance of inorganic PVK solar cells (PeSCs), a variety of strategies aiming to either passivate defects or enhance the electric field are developed. Nevertheless, a double‐aim strategy is less explored. Herein, a facile strategy of gradient doping is adopted for optimizing the inverted CsPbI₂Br PeSCs. Particularly, a bicationic iodine salt, namely 2,2′‐bis(trifluoromethyl)‐[1,1′‐biphenyl]‐4,4′‐diamine iodine (BFBAI₂), is used to realize gradient doping in PVK and ZnO layers, respectively. As a result, the inverted PeSCs with the doped PVK/ZnO bilayer deliver improves power conversion efficiency (PCE) up to 14.38% along with enhanced device stability under ambient or thermal aging conditions, greatly surpassing the pristine devices. The improvements are attributed principally to the low‐defect PVK layer as well as enhanced electric field across the inverted PeSCs upon gradient doping. This work thus demonstrates an efficient bifunctional strategy toward highly efficient and stable CsPbI₂Br PeSCs with inverted configuration.

One‐step synthesis of water‐soluble polyaniline derivatives is described. The newly designed material with excellent structure and electrical homogeneity is equipped with neutral pH and high conductivity compared with popular PEDOT:PSS. Herein, an efficient strategy to further develop conductive polymer is provided.

Among the various conducting polymers, polyaniline (PANI) has received a great deal of attention due to its low cost, excellent chemical and thermal stabilities, and high electrical conductivity. Herein, a newly designed self‐doped water‐soluble PANI derivatives‐poly (diphenylamine‐4‐sulfonic acid) (PDAS) is readily prepared and applied as hole extract layer in nonfullerene organic solar cells. PDAS, with satisfactory structural and electrical homogeneity, exhibits high conductivity of 7.75 × 10⁻² S cm⁻¹, none of acidity (with pH around 7), as well as enhanced work function of 5.43 eV, compared with the well‐known poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The power conversion efficiency of PDAS‐based devices is comparable with that of PEDOT:PSS‐based devices with the PM6:BTP‐4F‐12 as active layer. The successful design of the new self‐doped water‐soluble conductive polymer and its commercial application potential is demonstrated.

Transparent photovoltaics (TPVs) following the structure of indium tin oxide /MoO₃/ClAlPc:C₆₀/BCP/Cu:Ag/WO₃ are developed, which offer high average visible transmission of 77.45% with color rendering index of 91.9 and power conversion efficiency of 1.34%. Moreover, the TPV module can fully charge a 0.58 mAh LiFePO4(LFP)//Li battery, and directly drive an exciplex organic light‐emitting diode with a luminance of 180 cd m⁻².

Highly transparent photovoltaics (TPVs) integrated to a battery with small capacity can efficiently drive low‐powered internet of things (IoT) devices such as the receivers, sensors, actuators, etc. Such see‐through solar technology not only provides an opportunity to convert ambient light (sunlight or indoor lighting) to electricity but also demonstrates a concept of self‐sustainable power. In this work, a selective ultraviolet/near‐infrared bulk‐heterojunction active layer, i.e., chloroaluminum phthalocyanine (ClAlPc) as donor and C₆₀ as acceptor with a Cu:Ag/WO3 transparent electrode to visible lights are combined for achieving the vacuum‐deposited TPVs with a power conversion efficiency of 1.34%, average visible transmission of 77.45%, and color rendering index of 91.9. Moreover, a TPV module with a working area of 1.5 cm² is able to charge a 0.58 mAh LiFePO4(LFP)//Li battery fully within one hour under 100 mW cm^‐2 (≈1 sun) illumination. The TPV module can drive an exciplex organic light‐emitting diode with the electroluminescence >180 cd m⁻² at low illumination intensity of <5 mW cm^‐2. Overall, this work presents a significant step forward in the development of TPV technology towards integrating a display and storage battery, which could be successfully applied in wearable electronics requiring invisible and sustainable solar power.

The perovskite solar cells have emerged as one of the most promising candidates for next‐generation solar cells. However, their instability remains a grand challenge for practical applications. Here, we aim to enhance the stability and efficiency simultaneously by tuning the organic components in Ruddlesden−Popper perovskites (2D‐RPPs). Four groups of 2D‐RPPs are prepared and the influence of 4‐fluorophenethylammonium (FPEA) and formamidinium (FA) cations on the film properties and device performances are investigated. The (FPEA)₂(FA)₈Pb₉I₂₈ film is found to be exceptionally vertically orientated, showing enhanced charge transport and lower defect density. Its absorption edge substantially extends in infrared region, which greatly increases the photocurrent. A high efficiency of 16.15% along with a V _oc of 1.07 V and a J _sc of 20.88 mA cm⁻² is achieved for the (FPEA)₂(FA)₈Pb₉I₂₈ solar cell. Notably, the (FPEA)₂(FA)₈Pb₉I₂₈ film exhibits good humidity stability and remarkably enhanced thermal stability. Its unencapsulated device maintains 95% of its stating PCE after 2112 h when exposed to ambient air with 30‐70% RH, which is more superior than the reported (PEA)₂(MA)₈Pb₉I₂₈ and (FPEA)₂(MA)₈Pb₉I₂₈ solar cells. Our study demonstrates that enhanced performances of 2D‐RPPs can be obtained by strategically designing organic compositions, which paves an avenue towards the commercialization of 2D‐RPP devices.

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Strain tuning in Sb‐Chs was demonstrated by simultaneously replacing Sb and S with larger Bi and I ions, respectively. This strategy has been applied in Sb₂(S _x Se_{1– x} )₃ solar cells, and the champion cell exhibits a PCE of 7.05% under the standard illumination conditions (100 mW cm⁻²), which is one of the top efficiencies in solution processing Sb₂(S _x Se_{1– x} )₃ solar cells.

Abstract

Strain induced by lattice distortion is one of the key factors that affect the photovoltaic performance via increasing defect densities. The unsatisfied power conversion efficiencies (PCEs) of solar cells based on antimony chalcogenides (Sb‐Chs) are owing to their photoexcited carriers being self‐trapped by the distortion of Sb₂S₃ lattice. However, strain behavior in Sb‐Chs‐based solar cells has not been investigated. Here, strain tuning in Sb‐Chs is demonstrated by simultaneously replacing Sb and S with larger Bi and I ions, respectively. Bi/I codoped Sb₂S₃ cells are fabricated using poly[2,6‐(4,4‐bis(2‐ethylhexyl)‐4H‐cyclopenta[2,1‐b;3,4‐b']dithiophene)‐alt‐4,7‐(2,1,3‐enzothiadiazole)] as the hole‐transporting layer. Codoping reduced the bandgap and rendered a bigger tension strain (1.76 × 10⁻⁴) to a relatively smaller compression strain (−1.29 × 10⁻⁴). The 2.5 mol% BiI3 doped Sb₂S₃ cell presented lower trap state energy level than the Sb₂S₃ cell; moreover, this doping amount effectively passivated the trap states. This codoping shows a similar trend even in the low bandgap Sb₂(S_xSe_1‐x)₃ cell, resulting in 7.05% PCE under the standard illumination conditions (100 mW cm⁻²), which is one of the top efficiencies in solution processing Sb₂(S_xSe_1‐x)₃ solar cells. Furthermore, the doped cells present higher humidity, thermal and photo stability. This study provides a new strategy for stable Pb‐free solar cells.

Although high‐efficiency perovskite solar cells (PSCs) are typically fabricated in a glovebox, strategies to fabricate PSCs in ambient conditions hold many advantages and are often overlooked. Importantly, high‐efficiency ambient PSCs can only be achieved if specific adaptations to their processing conditions are made. This review provides important design rules to fabricate efficient PSCs in ambient conditions.

Abstract

Organic–inorganic hybrid perovskite solar cells (PSCs) have attracted significant attention in recent years due to their high‐power conversion efficiency, simple fabrication, and low material cost. However, due to their high sensitivity to moisture and oxygen, high efficiency PSCs are mainly constructed in an inert environment. This has led to significant concerns associated with the long‐term stability and manufacturing costs, which are some of the major limitations for the commercialization of this cutting‐edge technology. Over the past few years, excellent progress in fabricating PSCs in ambient conditions has been made. These advancements have drawn considerable research interest in the photovoltaic community and shown great promise for the successful commercialization of efficient and stable PSCs. In this review, after providing an overview to the influence of an ambient fabrication environment on perovskite films, recent advances in fabricating efficient and stable PSCs in ambient conditions are discussed. Along with discussing the underlying challenges and limitations, the most appropriate strategies to fabricate efficient PSCs under ambient conditions are summarized along with multiple roadmaps to assist in the future development of this technology.

Dynamic processes of mobile ions, as well as the interaction between charge carriers and mobile ions, are intimately correlated to the observed slow response in perovskites. Photoluminescence (PL) and time‐resolved PL (TRPL) imaging are unique tools to probe the dynamic processes of the slow response and the corresponding microscopic and temporal physical mechanisms.

Abstract

Halide perovskites are promising candidate materials for the next generation high‐efficiency optoelectronic devices. Since perovskites are electronic‐ionic mixed conductors, ion dynamics have a critical impact on the performance and stability of perovskite‐based applications. However, comprehensively understanding ionic dynamics is challenging, particularly on nanoscale imaging of ionic dynamics in perovskites. In this review, mobile ion dynamics in halide perovskites investigated via luminescence spectroscopy combined with confocal microscopy are discussed, including mobile ion induced fluorescence quenching, phase segregation in mixed halide hybrid perovskite, and mobile ion accumulation at the interface in perovskite devices. Steady‐state and time‐resolved luminescence imaging techniques, combined with confocal microscopy, are unique tools for probing ionic dynamics in perovskites, providing invaluable insights on ionic dynamics in nanoscale resolution, along with a wide temporal range from picoseconds to hours. The works in this review are not only for understanding mobile ions to improve the design of perovskite‐based devices but also foster the development of microspectroscopic methodologies in a broader solid‐state physics context of investigating ionic transports in polycrystalline materials.

Energy‐dispersive X‐ray spectroscopy in a scanning transmission electron microscope (STEM‐EDX) is performed on perovskite solar cells with methodically varied acquisition parameters to examine the relationship between electron dose, data quality, and beam damage. Five metrics are defined to quantify the statistical uncertainty in the STEM‐EDX data and extent of beam damage.

Abstract

Quantitative chemical analysis on the nanoscale provides valuable information on materials and devices which can be used to guide further improvements to their performance. In particular, emerging families of technologically relevant composite materials such as organic–inorganic hybrid halide perovskites and metal‐organic frameworks stand to benefit greatly from such characterization. However, these nanocomposites are also vulnerable to damage induced by analytical probes such as electron, X‐ray, or neutron beams. Here the effect of electrons on a model hybrid halide perovskite is investigated, focusing on the acquisition parameters appropriate for energy‐dispersive X‐ray spectroscopy in a scanning transmission electron microscope (STEM‐EDX). The acquisition parameters are systematically varied to examine the relationship between electron dose, data quality, and beam damage. Five metrics are outlined to assess the quality of STEM‐EDX data and severity of beam damage, further validated by dark field STEM imaging. Loss of iodine through vacancy creation is found to be the primary manifestation of electron beam damage in the perovskite specimen, and iodine content is seen to decrease exponentially with electron dose. This work demonstrates data acquisition and analysis strategies that can be used for studying electron beam damage and for achieving reliable quantification for a broad range of beam‐sensitive materials.

9.5% semitransparent solar cells with ultrahigh transmission in the visible range (50% AVT) are fabricated via inkjet printing. The effect of different photoactive layer ink solvents on the vertical stratification and performance is explored. The formulation of transport layer inks compatible with highly hydrophobic active layers and with scalable printing processes permits the use of a semitransparent electrode grid.

Abstract

New polymer donors and nonfullerene acceptors have elevated the performance and stability of solar cells to higher grounds. To achieve their full potential, they require their adaptation to scalable and cost‐effective solution manufacturing techniques for large area deposition. Likewise, formulating scalable solution‐based transport layer inks that are compatible with the photoactive layer is imperative. This manuscript reports the full integration of solution‐based transport layers and electrode alongside a PTB7‐Th:IEICO‐4F bulk heterojunction in inverted architecture through inkjet‐printing, resulting in power conversion efficiencies up to 12.4% opaque devices and 9.5% semitransparent devices with average visible transmittance values of 50.1%, including hole transport layer. The wetting envelope of the highly‐hydrophobic photoactive layer alongside the surface energy of candidate solutions and solvents allows the formulation of thick transport layer inks that are compatible with the drop‐on‐demand inkjet‐printing process and yield uniform and homogenous films. Moreover, the surface energy components of the donor and acceptor serves as a fingerprint to assess the vertical stratification of the photoactive layer with the inclusion of different solvents. This methodology addresses a scale‐up bottleneck of solution‐based transport layers for high‐efficiency organic cells, enabling its adaptation to high‐throughput techniques including slot‐die and roll‐to‐roll coating.

The present work deconvolutes the electronic processes in organic solar cells under short‐circuit conditions by combining readily available experimental methods (current‐voltage characteristics, external quantum efficiency) with optical simulations. The proposed method allows the quantification of geminate recombination, to determine the mobility‐lifetime product, and to quantify extraction. The applicability of this new approach is demonstrated in three different organic photovoltaic systems.

Abstract

The short‐circuit current (J _sc) of organic solar cells is defined by the interplay of exciton photogeneration in the active layer, geminate and non‐geminate recombination losses and free charge carrier extraction. The method proposed in this work allows the quantification of geminate recombination and the determination of the mobility‐lifetime product (µτ) as a single integrated parameter for charge transport and non‐geminate recombination. Furthermore, the extraction efficiency is quantified based on the obtained µτ product. Only readily available experimental methods (current‐voltage characteristics, external quantum efficiency measurements) are employed, which are coupled with an optical transfer matrix method simulation. The required optical properties of common organic photovoltaic (OPV) materials are provided in this work. The new approach is applied to three OPV systems in inverted or conventional device structures, and the results are juxtaposed against the µτ values obtained by an independent method based on the voltage–capacitance spectroscopy technique. Furthermore, it is demonstrated that the new method can accurately predict the optimal active layer thickness.

Novel asymmetric alkoxy and alkyl substitutions on the well‐known nonfullerene acceptor Y6 yield a molecule named Y6‐1O, and its photoelectric properties and photovoltaic performance are systematically compared with the two related symmetric molecules (Y6 and Y6‐2O), which suggests that this design strategy is promising and effective.

Abstract

In this paper, a strategy of asymmetric alkyl and alkoxy substitution is applied to state‐of‐the‐art Y‐series nonfullerene acceptors (NFAs), and it achieves great performance in organic solar cell (OSC) devices. Since alkoxy groups can have a significant influence on the material properties of NFAs, alkoxy substitution is applied to the Y6 molecule in a symmetric manner. The resulting molecule (named Y6‐2O), despite showing improved open‐circuit voltage (V _oc), yields extremely poor performance due to low solubility and excessive aggregation properties, a change that is due to the conformational locking effect of alkoxy groups. In contrast, asymmetric alkyl and alkoxy substitution on Y6, yields a molecule named Y6‐1O that can maintain the positive effect of V _oc improvement and obtain reasonably good solubility. The resulting molecule Y6‐1O enables highly efficient nonfullerene OSCs with 17.6% efficiency and the asymmetric side‐chain strategy has the potential to be applied to other NFA‐material systems to further improve their performance.

Two well‐regular polymer acceptors (PY‐IT and PY‐OT) with different polymerization sites are developed. For comparison, a random ternary copolymer (PY‐IOT) with the same ratio of the two acceptors is synthesized. All‐polymer solar cells (PSCs) based on PM6:PY‐IT achieve an excellent PCE of 15.05%, which is significantly higher than those based on PY‐OT (10.04%) and PY‐IOT (12.12%).

Abstract

Recent advances in the development of polymerized A–D–A‐type small‐molecule acceptors (SMAs) have promoted the power conversion efficiency (PCE) of all‐polymer solar cells (all‐PSCs) over 13%. However, the monomer of an SMA typically consists of a mixture of three isomers due to the regio‐isomeric brominated end groups (IC‐Br(in) and IC‐Br(out)). In this work, the two isomeric end groups are successfully separated, the regioisomeric issue is solved, and three polymer acceptors, named PY‐IT, PY‐OT, and PY‐IOT, are developed, where PY‐IOT is a random terpolymer with the same ratio of the two acceptors. Interestingly, from PY‐OT, PY‐IOT to PY‐IT, the absorption edge gradually redshifts and electron mobility progressively increases. Theory calculation indicates that the LUMOs are distributed on the entire molecular backbone of PY‐IT, contributing to the enhanced electron transport. Consequently, the PM6:PY‐IT system achieves an excellent PCE of 15.05%, significantly higher than those for PY‐OT (10.04%) and PY‐IOT (12.12%). Morphological and device characterization reveals that the highest PCE for the PY‐IT‐based device is the fruit of enhanced absorption, more balanced charge transport, and favorable morphology. This work demonstrates that the site of polymerization on SMAs strongly affects device performance, offering insights into the development of efficient polymer acceptors for all‐PSCs.

Two fully non‐fused acceptors are precisely designed and easily prepared. The side chain encapsulation can induce a planar molecular backbone conformation, endowing the acceptor with broad light absorption. Thermal annealing promotes molecular rearrangement to form J‐aggregates with even broader absorption and higher absorption coefficient. A PCE over 10 % is one of the highest PCE for fully non‐fused ring acceptors.

Abstract

Fused‐ring electron acceptors have made significant progress in recent years, while the development of fully non‐fused ring acceptors has been unsatisfactory. Here, two fully non‐fused ring acceptors, o‐4TBC‐2F and m‐4TBC‐2F, were designed and synthesized. By regulating the location of the hexyloxy chains, o‐4TBC‐2F formed planar backbones, while m‐4TBC‐2F displayed a twisted backbone. Additionally, the o‐4TBC‐2F film showed a markedly red‐shifted absorption after thermal annealing, which indicated the formation of J‐aggregates. For fabrication of organic solar cells (OSCs), PBDB‐T was used as a donor and blended with the two acceptors. The o‐4TBC‐2F‐based blend films displayed higher charge mobilities, lower energy loss and a higher power conversion efficiency (PCE). The optimized devices based on o‐4TBC‐2F gave a PCE of 10.26 %, which was much higher than those based on m‐4TBC‐2F at 2.63 %, and it is one of the highest reported PCE values for fully non‐fused ring electron acceptors.

It is challenging to grow single‐crystal halide perovskite films with large lateral size and much thinner thickness. A surface energy modifying strategy was proposed that achieves anisotropic growth, freestanding single‐crystal CsPbBr₃ halide perovskite films with a thickness less than 100 nm and a lateral size close to one centimeter.

Abstract

It is extremely challenging to grow single‐crystal halide perovskite films (SCHPFs) with not only desired transport properties but also large lateral size with much thinner thickness. Here, we report the growth of freestanding single crystal CsPbBr₃ SCHPFs with thickness less than 100 nm and a lateral size close to centimeter for the first time. A new model for growth kinetics (Ψ=Aexp[−(E_A−E_s)/(k_BT)]) is proposed to address the surface energy and temperature effect on the growth rate of ultrathin CsPbBr₃ single‐crystal film. The experimental results and DFT calculations both demonstrated that the surfactant plays a critical role in modifying the surface energy and achieving anisotropic growth. This work opens new opportunities for high‐quality SCHPFs with large lateral size and controllable thickness that may find wide applications for optoelectronic devices.

Publication date: 20 January 2021

Source: Joule, Volume 5, Issue 1

Author(s): Yunlong Ma, Ming Zhang, Shuo Wan, Pan Yin, Pengsong Wang, Dongdong Cai, Feng Liu, Qingdong Zheng