Perovskite Optoelectronics Research Articles

Natural and Nature-Inspired Biomaterial Additives for Metal Halide Perovskite Optoelectronics.

This comprehensive review meticulously categorizes and discusses the applications of diverse biomaterials, specifically natural and nature-inspired synthetic materials in metal halide perovskite optoelectronics. Applications range from solar cells to light-emitting diodes, photodetectors, and X-ray detectors. Emphasis is placed on the intricate interactions between bio-additives and perovskite crystals, highlighting their influence on the grain size, crystal orientation, grain boundaries, and surface passivation. This review also explores the advantages and disadvantages of each natural or nature-inspired material and their unique properties compared with conventional additives. Special attention is given to the mechanistic and functional viewpoints, showing how these biomaterials enhance device performance. Through additive engineering with ecofriendly biomaterials, defects in metal halide perovskite thin films can be effectively passivated, thus extending the photostability or in some cases mechanical flexibility of devices. This review provides valuable insights for selecting and designing next-generation biomaterial additives, offering new prospects for achieving high-performance perovskite layers and advancing the field of peorvskite- based optoelectronics.

Leveraging Phenazine‐Based Ligands for Optimized Perovskite Optoelectronic Performance Through Chelation and Redox Engineering

AbstractPerovskite nanocrystals (PNCs) hold immense potential for optoelectronic and photovoltaic applications. However, their performance is hindered by surface defects that promote non‐radiative recombination and reduce stability. Surface engineering, particularly through defect passivation, is crucial for achieving high‐performing perovskite solar cells. Chelation has been shown to significantly improve the efficiency and stability of perovskite solar cells. In this study, a novel chelation strategy using 1,10‐Phenanthroline (Phen) is presented as a bidentate chelating ligand to effectively target and passivate these detrimental surface defects. By strategically designing a Phenanthroline derivative, dipyrido[3,2‐a:2′,3′‐c]phenazin‐11‐amine (Phen‐derivative) with optimized redox potentials, dual functionality: efficient defect passivation and hole transport is achieved. X‐ray photoelectron spectroscopy (XPS) confirms the superior binding capability of the Phen‐derivative due to chelation. This strong interaction facilitates efficient and ultrafast charge transfer from PNCs and the formation of a long‐lived charge‐separated state, as evidenced by sustained bleaching in transient absorption spectra. A metal‐dipyrido[3,2‐a:2′,3′‐c]phenazin‐11‐amine complex (Ir‐complex) derived from dipyrido[3,2‐a:2′,3′‐c]phenazin‐11‐amine, but lacking a chelation site, hinders desired hole transfer despite similar charge transfer energetics. This work emphasizes the critical role of chelation‐mediated interfacial interactions and energy alignment in designing effective charge shuttle molecules and unlocking the potential of lead‐chelating hole transporters for next‐generation light‐harvesting technologies.

Application and Research Progress of Perovskite in the Field of Optoelectronic Materials

Perovskite refers to a class of materials with the formula of ABO3. These oxides were first discovered in calcium titanate compounds. Perovskite materials have attracted widespread attention in the field of contemporary photovoltaic research due to their excellent photovoltaic properties, heralding their potential as protagonists of a new generation of photovoltaic materials. Nevertheless, the stability of perovskite materials needs to be enhanced. In addition, reducing the toxicity of the materials is a key challenge in advancing their commercialization. Currently, the rapid development of perovskite in the field of optoelectronics and its unique combination of properties have laid a solid foundation for its position as a mainstream optoelectronic material of the future. Therefore, this work focuses on the properties and applications of perovskite optoelectronics. With deeper scientific research and technological innovation, perovskites have the potential to overcome existing limitations and move towards large-scale commercial production. In the future, the further application of perovskite optoelectronic materials would have far-reaching implications for the global energy transition and environmental protection.

Plasmonic molybdenum carbide MXene nanosheets for highly efficient and stable perovskite solar cells

Besides the excellent metallic electrical conductivity, high carrier mobility, and high optical transmittance, the two-dimensional MXenes exhibiting impressive optical and plasmonic properties have been explored to photodiodes. However, their potential use of surface plasmons oscillating in perovskite solar cells has not been studied. Herein, we incorporate, for the first time, Mo2CTx MXene nanosheets with characteristic plasmonic absorption in the whole visible region into the perovskite active layer. First, the presence of Mo2CTx nanosheets in the perovskite film increases the perovskite grain size due to the decreased growth rate and passivation of the defects around the grain boundaries through strong interaction with undercoordinated Pb2+. Furthermore, with the help of the localized surface plasmon resonance effect of Mo2CTx nanosheets, the exciton binding energy in the perovskite absorber is reduced, which suggests the efficient exciton dissociation and enhanced charge separation. Consequently, Mo2CTx nanosheets based perovskite solar cell device exhibits a champion power conversion efficiency (PCE) of 24.05 %. It is worth noting that the unencapsulated devices demonstrate considerably improved stability, maintaining about 89.25 % of the initial PCE after aging in air for 3000 h. This fascinating strategy provides more opportunities of the functional MXene materials for the perovskite optoelectronics.

Machine learning for perovskite optoelectronics: a review

Machine learning for perovskite optoelectronics: a review

Triiodide Formation Governs Oxidation Mechanism of Tin-Lead Perovskite Solar Cells via A-Site Choice.

Mixed tin-lead (Sn-Pb) halide perovskites stand out as promising materials for next-generation photovoltaics and near-infrared optoelectronics. However, their sensitivity to oxidative degradation remains a major hurdle toward their widespread deployment. A holistic understanding of their oxidation processes considering all their constituent ions is therefore essential to stabilize these materials. Herein, we reveal that A-site cation choice plays an inconspicuous yet crucial role in determining Sn-Pb perovskite stability toward oxidation. Comparing typical A-site compositions, we show that thin films and solar cells containing cesium are more resistant to oxidative stress relative to their methylammonium analogs. We identify degradation in these compositions to be closely linked to the presence of triiodide, a harmful species evolving from native I2 oxidants. We find that hydrogen bonding between methylammonium and I2 promotes triiodide formation, while the strong polarizing character of cesium limits this process by capturing I2. Inspired from these findings, we design two strategies to boost stability of sensitive methylammonium-based Sn-Pb perovskite films and devices against oxidation. Specifically, we modulate the polarizing character of surface A-sites in perovskite via CsI and RbI coatings, and we incorporate Na2S2O3 as an I2 scavenging additive. These crucial mechanistic insights will pave the way for the design of highly efficient and stable Sn-Pb perovskite optoelectronics.

Interfacial Engineering for Controlled Crystal Mosaicity in Single-Crystalline Perovskite Films.

Organic-inorganic hybrid perovskites have attracted significant attention for optoelectronic applications due to their efficient photoconversion properties. However, grain boundaries and irregular crystal orientations in polycrystalline films remain issues. This study presents a method for producing crystalline-orientation-controlled perovskite single-crystal films using retarded solvent evaporation. It is shown that single-crystal films, grown via inverse temperature crystallizationwithin a confined space, exhibit enhanced optoelectronic property. Using interfacial polymer layer, this method produces high-quality perovskite single-crystalline films with varying crystal orientations. Density functional theory calculations confirm favorable adsorption energies for (110) surfaces with methylammonium iodide and PbI2 terminations on poly(3-hexylthiophene), and stronger adsorption for (224) surfaces with I and methylammonium terminations on polystyrene, influenced by repulsive forces between the thiophene group and the perovskite surface. The correlation between charge transport characteristics and perovskite single-crystalline properties highlights potential advancements in perovskite optoelectronics, improving device performance and reliability.

Evaluating Fluorinated-Aniline Units with Functionalized Spiro[Fluorene-9,9'-Xanthene] as Hole-Transporting Materials in Perovskite Solar Cells and Light-Emitting Diodes.

In the field of perovskite optoelectronics, developing hole-transporting materials (HTMs) on the spiro[fluorene-9,9'-xanthene] (SFX) platform is one of the current research focuses. The SFX inherits the merits of spirobifluorene in terms of the configuration and property, but it is more easily derivatized and regulated by virtue of its binary structure. In this work, we design and synthesize four isomeric SFX-based HTMs, namely m-SFX-mF, p-SFX-mF, m-SFX-oF, and p-SFX-oF, through varying the positions of fluorination on the peripheral aniline units and their substitutions on the SFX core, and the optoelectronic performance of the resulting HTMs is evaluated in both perovskite solar cells (PSCs) and light-emitting diodes (PeLEDs) by the vacuum thermal evaporating hole-transporting layers (HTLs). The HTM p-SFX-oF exhibits an improved power conversion efficiency of 15.21% in an inverted PSC using CH3NH3PbI3 as an absorber, benefiting from the deep HOMO level and good HTL/perovskite interface contact. Meanwhile, the HTM m-SFX-mF provides a maximum external quantum efficiency of 3.15% in CsPb(Br/Cl)3-based PeLEDs, which is attributed to its perched HOMO level and shrunken band-gap for facilitating charge carrier injection and then exciton combination. Through elucidating the synergistic position effect of fluorination on aniline units and their substitutions on the SFX core, this work lays the foundation for developing low-cost and efficient HTMs in the future.

Ultrafast Photoexcitation Induced Passivation for Quasi-2D Perovskite Photodetectors.

Quasi-2D perovskites exhibit great potential in photodetectors due to their exceptional optoelectronic responsivity and stability, compared to their 3D counterparts. However, the defects are detrimental to the responsivity, response speed, and stability of perovskite photodetectors. Herein, an ultrafast photoexcitation-induced passivation technique is proposed to synergistically reduce the dimensionality at the surface and induce oxygen doping in the bulk, via tuning the photoexcitation intensity. At the optimal photoexcitation level, the excited electrons and holes generate stretching force on the Pb─I bonds at the interlayered [PbI6]-, resulting in low dimensional perovskite formation, and the absorptive oxygen is combined with I vacancies at the same time. These two induced processes synergistically boost the carrier transport and interface contact performance. The most outstanding device exhibits a fast response speed with rise/decay time of 201/627ns, with a peak responsivity/detectivity of 163 mA W-1/4.52 × 1010 Jones at 325nm and the enhanced cycling stability. This work suggests the possibility of a new passivation technique for high performance 2D perovskite optoelectronics.

Van der Waals Integration of Large-Area Monocrystalline 3D Perovskite Thin Films on Arbitrary Semiconductor Substrates for Heterojunctions.

Perovskite monocrystalline films are regarded as desirable candidates for the integration of high-performance optoelectronics due to their unique photophysical properties. However, the heterogeneous integration of a perovskite monocrystalline film with other semiconductors is fundamentally limited by the lattice mismatch, which hinders direct epitaxy. Herein, the van der Waals (vdW) integration strategy for 3D perovskites is developed, where perovskite monocrystalline films are epitaxially grown on the mother substrate, followed by its peeling off and transferring to arbitrary semiconductors, forming monocrystalline heterojunctions. The as-achieved CsPbBr3-Nb-doped SrTiO3 (Nb:STO) vdW p-n heterojunction exhibited comparable performance to their directly epitaxial counterpart, demonstrating the feasibility of vdW integration for 3D perovskites. Furthermore, the vdW integration could be extended to silicon substrates, rendering the CsPbBr3-n-Si and CsPbCl3-p-Si p-n heterojunction with apparent rectification behaviors and photoresponse. The vdW integration significantly enriches the selections of semiconductors hybridizing with perovskites and provides opportunities for monocrystalline perovskite optoelectronics with complex configurations and multiple functionalities.

CH3NH3SnI3${\mathrm{CH}}_{\mathrm{3}}{\mathrm{NH}}_{\mathrm{3}}{\mathrm{SnI}}_{\mathrm{3}}$: Superior Light Absorption and Optimized Device Architecture with 31.93% Efficiency

AbstractThis research investigates and optimizes the perovskite solar cells. Initially, optoelectronic parameters of perovskite absorber materials, including , , and , are estimated using Density Functional Theory (DFT) principles implemented in the Quantum Espresso software. The absorption of light energy is examined, detailing electron transitions between the highest p energy states of halogens (I, Br, and Cl) in the VB and the lowest 5p energy states of tin in the CB. shows superior optical characteristics, surpassing and , and demonstrating more effective absorption within the visible spectrum than . Subsequently, a numerical analysis is conducted for a P–I–N configuration Fluorine doped Tin Oxide (FTO)////Anode using SCAPS‐1D software. The optimization process focuses on absorber thickness, defect density, acceptor density, and the work function (WF) of the anode materials. Simulation findings recommend a defect density () of for optimal performance, coupled with an absorber thickness of 1 µm. Examining the transformation from to through oxidation reveals that reducing the concentration of acceptors in the absorber layer (NA) significantly enhances device performance. Superior performance is achieved by a high WF anode material. This study not only contributes to advancing our understanding of lead‐free perovskite optoelectronics but also provides valuable insights for the development of highly efficient and stable solar cells.

Single Crystal Perovskite/Graphene Self-Driven Photodetector with Fast Response Speed.

Recently, the combination of two-dimensional (2D) materials and perovskites has gained increasing attention in optoelectronic applications owing to their excellent optical and electrical characteristics. Here, we report a self-driven photodetector consisting of a monolayer graphene sheet and a centimeter-sized CH3NH3PbBr3 single crystal, which was prepared using an optimized wet transfer method. The photodetector exhibits a short response time of 2/30 μs by virtue of its high-quality interface, which greatly enhances electron-hole pair separation in the heterostructure under illumination. In addition, a responsivity of ~0.9 mA/W and a detectivity over 1010 Jones are attained at zero bias. This work inspires new methods for preparing large-scale high-quality perovskite/2D material heterostructures, and provides a new direction for the future enhancement of perovskite optoelectronics.

Organic A‐Site Cations Improve the Resilience of Inorganic Lead‐Halide Perovskite Nanocrystals to Surface Defect Formation

AbstractLead halide perovskite nanocrystals (LHP NCs) are generally prone to surface defect formation during the purification process, resulting in a reduced photoluminescence (PL) quantum yield. The purification of LHP NCs using antisolvents leads to the detachment of surface atoms and ligandsin the form of alkylammonium‐halides or A‐carboxylates (A: Cs, methylammonium, MA, or formamidinium, FA. Currently, intense research is being carried out to improve the surface stability of LHP NCs using various long‐chain organic ligands that strongly bind to the surface of NCs. Herein, the findings on the higher surface stability of hybrid (MAPbBr3 and FAPbBr3) LHP NCs compared to that of inorganic CsPbBr3 NCs against purification with polar antisolvents are reported. It is discovered that the CsPbBr3 NC surface stability can be enhanced (reaching that of hybrid perovskite NCs) by the incorporation of a small amount of MA or FA A‐site organic cations into their lattice, corroborated by the evidence that the PL quantum yield of mixed A‐cation CsxFA1‐xPbBr3 and CsxMA1‐xPbBr3 NCs remains unaffected after several purification cycles. It is hypothesized that this is attributed to hydrogen bonding between the organic A‐site cations and the neighboring halides on the surface. These findings are not only fundamentally important but are also expected to have wide implications in the field of metal‐halide perovskite optoelectronics.

Solid-State Anion Exchange Enabled by Pluggable vdW Assembly for In Situ Halide Manipulation in Perovskite Monocrystalline Film.

The fabrication of perovskite single crystal-based optoelectronics with improved performance is largely hindered by limited processing techniques. Particularly, the local halide composition manipulation, which dominates the bandgap and thus the formation of heterostructures and emission of multiple-wavelength light, is realized via prevalent liquid- or gas-phase anion exchange with the utilization of lithography, while the monocrystalline nature is sacrificed due to polycrystalline transition in exchange with massive defects emerging, impeding carrier separation and transportation. Thus, a damage-free and lithography-free solid-state anion exchange strategy, aiming at in situ halide manipulation in perovskite monocrystalline film, is developed. Typically, CsPbCl3 working as medium to deliver halide is van der Waals (vdW) assembled to specific spots of CsPbBr3, followed by the removal of CsPbCl3 after anion exchange, with the halide composition in contact area modulated and monocrystalline nature of CsPbBr3 preserved. CsPbBr3-CsPbBrxCl3-x monocrystalline heterostructure has been achieved without lithography. Device based on the heterostructure shows apparent rectification behavior and improved photo-response rate. Heterostructure arrays can also be constructed with customized medium crystal. Furthermore, the halide composition can be accurately tuned to enable full coverage of visible spectra. The solid-state exchange enriches the toolbox for processing vulnerable perovskite and paves the way for the integration of monocrystalline perovskite optoelectronics.

Efficient Homojunction Tin Perovskite Solar Cells Enabled by Gradient Germanium Doping.

P-type self-doping is known to hamper tin-based perovskites for developing high-performance solar cells by increasing the background current density and carrier recombination processes. In this work, we propose a gradient homojunction structure with germanium doping that generates an internal electric field across the perovskite film to deplete the charge carriers. This structure reduces the dark current density of perovskite by over 2 orders of magnitude and trap density by an order of magnitude. The resultant tin-based perovskite solar cells exhibit a higher power conversion efficiency of 13.3% and excellent stability, maintaining 95% and 85% of their initial efficiencies after 250 min of continuous illumination and 3800 h of storage, respectively. We reveal the homojunction formation mechanism using density functional theory calculations and molecular level characterizations. Our work provides a reliable strategy for controlling the spatial energy levels in tin perovskite films and offers insights into designing intriguing lead-free perovskite optoelectronics.

Two-Terminal Perovskite Optoelectronic Synapse for Rapid Trained Neuromorphic Computation with High Accuracy.

Emerging neural morphological vision sensors inspired by biological systems that integrate image perception, memory, and information computing are expected to transform the landscape of machine vision and artificial intelligence. However, stable and reconfigurable light-induced synaptic behavior always relies on independent gateport modulation. Despite its potential, the limitations of uncontrollable defects and ionic characteristics have led to simpler, smaller, and more integration-friendly two-terminal devices being used as sidelines. In this work, the synergy between ion migration barriers and readout voltage is proven to be the key to realizing stable, reconfigurable, and precisely controllable postsynaptic current in two-terminal devices. Following the same mechanism, optical and electrical signal synchronous triggering is proposed to serve as a preprocessing method to achieve a recognition accuracy of 96.5%. Impressively, the gradual ion accumulation during the training process induces photocurrent evolution, serving as a reference for the dynamic learning rate and boosting accuracy to 97.8% in just 10 epochs. The PSC modulation potential under short optical pulse of 20 ns is also revealed. This optoelectronic device with perception, memory, and computation capabilities can promote the development of new devices for future photonic neural morphological circuits and artificial vision.

Kornblum Oxidation Reaction-Induced Collective Transformation of Lead Polyhalides for Stable Perovskite Photovoltaics.

The iodide vacancy defects generated during the perovskite crystallization process are a common issue that limits the efficiency and stability of perovskite solar cells (PSCs). Although excessive ionic iodides have been used to compensate for these vacancies, they are not effective in reducing defects through modulating the perovskite crystallization. Moreover, these iodide ions present in the perovskite films can act as interstitial defects, which are detrimental to the stability of the perovskite. Here, an effective approach to suppress the formation of vacancy defects by manipulating the coordination chemistry of lead polyhalides during perovskite crystallization is demonstrated. To achieve this suppression, an α-iodo ketone is introduced to undergo a process of Kornblum oxidation reaction that releases halide ions. This process induces a rapid collective transformation of lead polyhalides during the nucleation process and significantly reduces iodide vacancy defects. As a result, the ion mobility is decreased by one order of magnitude in perovskite film and the PSC achieves significantly improved thermal stability, maintaining 82% of its initial power conversion efficiency at 85°C for 2800h. These findings highlight the potential of halide ions released by the Kornblum oxidation reaction, which can be widely used for achieving high-performance perovskite optoelectronics.

Halide Ion Mobility in Paired 2D Halide Perovskites: Ruddlesden–Popper Versus Dion–Jacobson Phases

Abstract2D lead halide perovskites with tunable optoelectronic properties through modulating inorganic components and organic spacer ligands represent a promising candidate in perovskite optoelectronics. However, an intrinsic soft lattice of perovskites gives rise to a vacancy‐mediated halide ion migration, which further affects the long‐term stability of materials as well as devices. Here, halide ion mobility is evaluated using two different 2D perovskites yielded with butylammonium (BA) for the Ruddlesden–Popper (RP) phase and butane‐1,4‐diamine (BDA) for the Dion–Jacobson (DJ) phase, respectively. By probing the halide ion migration kinetics in the physically paired 2D bromide and iodide perovskite films, the softer lattice (RP) shows a lower activation energy of 50.9 kJ mol−1 as compared to that of more rigid lattice (DJ) of 60.8 kJ mol−1. Given similar halide diffusion pathlength and halide mixing chemical potential, the binding mode (RP and DJ) can indeed dictate the overall halide ion stability. Understanding such halide ion mobility is important in designing perovskites with increased stability and performances at material and device levels.

Recent Advances in Optical Properties and Light‐Emitting Diode Applications for 2D Tin Halide Perovskites

AbstractLead halide perovskites are widely used and intensively studied in optoelectronic devices due to their superior properties. However, the toxicity of Pb hinders the industrialization of perovskite optoelectronic devices. Sn has a similar electronic structure to Pb, thus has been widely studied as an alternative to Pb‐based perovskite optoelectronics in recent years. In this review, the research progress in luminescent properties and synthesis methods of 2D tin halide perovskites are summarized. It is also highlight a unique dual emission phenomenon in 2D tin halide perovskites and summarize several types of possible luminous mechanisms. At last, the recent development of 2D tin halide perovskites based light‐emitting diodes are also overviewed, and the challenges of oxidative inhibition and efficiency improvement in 2D tin halide perovskites are discussed. This review is expected to provide a comprehensive perspective on luminescent properties and light‐emitting diode applications of 2D tin halide perovskites.

Atomic insights into the optoelectronic properties of vacancy-ordered double perovskite halide semiconductors

Vacancy-ordered halide perovskite Cs2BX6 semiconductors are attracting an increasing level of interest for optoelectronic applications due to their high chemical stability and unique light emission properties. Here, we performed first-principles calculations to determine the energy positions and atomic orbital hybridization features of band edge states in Cs2BX6 (B = Ge, Sn, Te, Ti, Zr, Hf; X = Cl, Br, I). Our results revealed that all the Cs2BX6 perovskites, except for Cs2TeX6, have direct bandgaps at the Γ point. The indirect bandgaps of Cs2TeX6 originate from the symmetry-forbidden Te p–X p coupling at the Γ point. Both energy positions and dispersions of the band edge states of Cs2BX6 can be well modulated by varying X- and B-site ions. Our work provides a comprehensive understanding of electronic structures and optoelectronic properties of Cs2BX6 perovskites, shedding light on the design rules for high-performance perovskite optoelectronics.