Energy Level Alignment Research Articles

Effect of Bridging Manner on the Transport Behaviors of Dimethyldihydropyrene/Cyclophanediene Molecular Devices.

A molecule-electrode interface with different coupling strengths is one of the greatest challenges in fabricating reliable molecular switches. In this paper, the effects of bridging manner on the transport behaviors of a dimethyldihydropyrene/cyclophanediene (DHP/CPD) molecule connected to two graphene nanoribbon (GNR) electrodes have been investigated by using the non-equilibrium Green's function combined with density functional theory. The results show that both current values and ON/OFF ratios can be modulated to more than three orders of magnitude by changing bridging manner. Bias-dependent transmission spectra and molecule-projected self-consistent Hamiltonians are used to illustrate the conductance and switching feature. Furthermore, we demonstrate that the bridging manner modulates the electron transport by changing the energy level alignment between the molecule and the GNR electrodes. This work highlights the ability to achieve distinct conductance and switching performance in single-molecular junctions by varying bridging manners between DHP/CPD molecules and GNR electrodes, thus offering practical insights for designing molecular switches.

Self‐doped conjugated polymers with electron‐deficient quinone units for enhanced electron transport in highly efficient organic solar cells

AbstractOrganic solar cells (OSCs) have attracted significant attention as a burgeoning flexible technology, owing to their advanced power conversion efficiencies. Moreover, interface materials play a crucial role in optimizing energy level alignment between the active layer and electrodes, thereby enhancing carrier extraction within the device and improving efficiency. However, current methodologies for fabricating electron‐transport materials with superior mobility are still limited compared with those for hole‐transport materials. In this study, a benzodifurandione (BFDO)‐derived building block with quinone resonance property and strong electron‐withdrawing capability was synthesized. Two conjugated polymers, namely PBFDO‐F6N and PBFDO‐F6N‐Br, were prepared, both of which exhibited good electron mobility and exceptional interface modification capabilities. A comprehensive investigation of the interaction between the interface layer and the active layer revealed that PBFDO‐F6N induced doping at the acceptor interface. Additionally, the high mobility of PBFDO‐F6N facilitated efficient carrier extraction at the interface. Consequently, the application of PBFDO‐F6N as the cathode interface layer for PM6:BTP‐eC9‐based OSC devices resulted in a remarkable efficiency of 18.11%. Moreover, the device efficiency remained at ∼96% even at a PBFDO‐F6N interface thickness of 50 nm, demonstrating the great potential of this material for large‐scale device preparation.

Anions Regulation of 1D Perovskite Intrusion-Behavior for Efficient and Stable Perovskite Solar Cells.

Constructing a 1D/3D perovskite heterojunction has recently emerged as a prevalent approach for elevating the efficiency and stability of perovskite solar cells (PSCs), due to the excellent defect-passivation capacity and enhanced resistance to water and oxygen of 1D perovskite. However, the 1D perovskite commonly exhibits much poorer charge carrier transport ability when compared with its 3D counterpart. Tailoring the intrusion depth of a 1D perovskite into the 1D/3D heterojunction is thus of key importance for PSCs but remains a great challenge. We introduce herein a novel anion-regulation strategy that can effectively tune the intrusion behavior of 1D perovskite into 3D perovskite to form a 1D/3D heterojunction with gradual structure and gradient energy-level alignment. This gradual 1D/3D-perovskite interface leads to outstanding defect passivation performance, together with a desired balance between charge transport and moisture/oxygen blocking. Consequently, the PSCs with a 1D/3D perovskite heterojunction resulting from tetra-n-butylammonium acetate (TBAAc) treatment yield a remarkable enhancement in power conversion efficiency (PCE) from 18.4 to 20.1%. The unencapsulated device also demonstrates excellent stability and retains 90% of its initial PCE after 2400 h of storage in the air atmosphere with 30 ± 5% humidity at 25 ± 5 °C.

Rational Design and Engineering of Terminal Functional Groups in Dibenzothiophene‐Diphenylamine Small Molecular Electron Donors for Enhanced Photovoltaic Efficiency in All‐Small‐Molecule Organic Solar Cells

AbstractAll‐small‐molecule organic solar cells (ASM‐OSCs) offer advantages like well‐defined molecular structures and excellent reproducibility. However, lower photovoltaic efficiencies hinder their adoption due to limitations in designing small molecular electron donors (SMEDs) with optimal energy levels, light absorption, and optoelectronic properties. The present study addresses this gap by rationally designing a series of SMEDs (DBT‐2FA1 to DBT‐2FA6) through terminal acceptors engineering into dibenzothiophene core with diphenylamine side donors for potential applications in ASM‐OSCs. Density functional theory simulations are carried‐out to establish structure‐property relationships based on structural, electrochemical, photophysical, and charge transfer (CT) properties. Results show that the SMEDs exhibit low‐lying HOMOs for suitable energy level alignment with benchmark Y6 acceptor, promoting open‐circuit voltage and charge separation. The panchromatic absorption spectra covering Vis‐NIR region and maximum light harvesting efficiency are beneficial for high current‐density in ASM‐OSCs. Notably, the push‐pull mechanism within SMEDs results in dominant intramolecular CT with above 70% CT excitations. Whereas, a moderate variation in dipole moments and electrostatic potential differences with acceptor material led to 99.9% intermolecular CT, thus ensuring robust exciton dissociation and efficient photocurrent generation. Overall, this work provides a molecular‐level understanding of designing novel SMEDs and their compatibility with acceptor materials for developing future high‐performance ASM‐OSCs.

Lowering Charge Transport Barriers by Eliminating the Electric Double Layer Residues to Reconstruct Adjacent SnO2 Nanocrystals for High‐Efficiency Flexible Perovskite Solar Cells

AbstractThe sol–gel method is efficient and cost‐effective for synthesizing SnO2 sol, wherein SnO2 nanocrystallites (NCs) are stabilized by electric double‐layer of solvated ions tightly bound to their surface. However, this strong binding makes the removal of electric double‐layer residues from the SnO2 electron transport layer (ETL) to be difficult at low temperatures. This hinders both the close contact and subsequent growth among adjacent SnO2 NCs, leading to severe carriers scattering at grain boundary, adversely affecting the electrical properties of SnO2 ETL. Herein, SnO2 sol is synthesized via an ethanol‐based sol–gel method and aqueous ammonia (NH3·H2O) is introduced to effectively clean stubborn electric double‐layer residues within the SnO2 ETL at a low temperature (80 °C). Removing residues reduces the gap among adjacent SnO2 NCs and promotes further reconstructed growth through oriented attachment (OA), thereby reducing the number of grain boundaries. Hence, the energy barriers for electron transport decrease within the SnO2 ETL. Furthermore, MHP prepared on the treated ETL has fine‐tuned energy level alignment, improving the electron extraction capacity. Consequently, flexible perovskite solar cells (f‐PSCs) incorporating this ETL achieved a notable increase in power conversion efficiency, rising from 19.16% to 23.71%, as well as superior mechanical stability.

Enhanced performance of perovskite solar cell via up-conversion YLiF4:Yb, Er nanoparticles

We report a simple and effective method for producing lanthanide ion-doped lithium-fluoride-based nanocrystals (YLiF4). We utilized those nanoparticles for up-conversion in fabricated perovskite solar cells. The obtained results shows that the up-conversion YLiF4:Yb, Er nanoparticles improve alignment of energy levels at interface between titanium dioxide and perovskite layer. This increases power conversion efficiency of fabricated perovskite solar cells from 19.45 % to 21.32 %. To enhance comprehension of the recombination mechanism and its correlation with the conduction band offset and defects, device models are additionally integrated into the SCAPS simulator. Subsequently, the obtained J-V simulation outcomes exhibit a favorable concordance with the experimental observations.

Enhancement of Efficiency of Perovskite Solar Cells with Hole-Selective Layers of Rationally Designed Thiazolo[5,4-d]thiazole Derivatives.

We introduce thiazolo[5,4-d]thiazole (TT)-based derivatives featuring carbazole, phenothiazine, or triphenylamine donor units as hole-selective materials to enhance the performance of wide-bandgap perovskite solar cells (PSCs). The optoelectronic properties of the materials underwent thorough evaluation and were substantially fine-tuned through deliberate molecular design. Time-of-flight hole mobility TTs ranged from 4.33 × 10-5 to 1.63 × 10-3 cm2 V-1 s-1 (at an electric field of 1.6 × 105 V cm-1). Their ionization potentials ranged from -4.93 to -5.59 eV. Using density functional theory (DFT) calculations, it has been demonstrated that S0 → S1 transitions in TTs with carbazolyl or ditert-butyl-phenothiazinyl substituents are characterized by local excitation (LE). Mixed intramolecular charge transfer (ICT) and LE occurred for compounds containing ditert-butyl carbazolyl-, dimethoxy carbazolyl-, or alkoxy-substituted triphenylamino donor moieties. The selected derivatives of TT were used for the preparation of hole-selective layers (HSL) in PSC with the structure of glass/ITO/HSLs/Cs0.18FA0.82Pb(I0.8Br0.2)3/PEAI/PC61BM/BCP/Ag. The alkoxy-substituted triphenylamino containing TT (TTP-DPA) has been demonstrated to be an effective material for HSL. Its layer also functioned well as an interlayer, improving the surface of control HSL_2PACz (i.e., reducing the surface energy of 2PACz from 66.9 to 52.4 mN m-1), thus enabling precise control over perovskite growth energy level alignment and carrier extraction/transportation at the hole-selecting contact of PSCs. 2PACz/TTP-DPA-based devices showed an optimized performance of 19.1 and 37.0% under 1-sun and 3000 K LED (1000 lx) illuminations, respectively. These values represent improvements over those achieved by bare 2PACz-based devices, which attained efficiencies of 17.4 and 32.2%, respectively. These findings highlight the promising potential of TTs for the enhancement of the efficiencies of PSCs.

Stable pure-green organic light-emitting diodes toward Rec.2020 standard

Manipulating dynamic behaviours of charge carriers and excitons in organic light-emitting diodes (OLEDs) is essential to simultaneously achieve high colour purity and superior operational lifetime. In this work, a comprehensive transient electroluminescence investigation reveals that incorporating a thermally activated delayed fluorescence assistant molecule with a deep lowest unoccupied molecular orbital into a bipolar host matrix effectively traps the injected electrons. Meanwhile, the behaviours of hole injection and transport are still dominantly governed by host molecules. Thus, the recombination zone notably shifts toward the interface between the emissive layer (EML) and the electron-transporting layer (ETL). To mitigate the interfacial carrier accumulation and exciton quenching, this bipolar host matrix could serve as a non-barrier functional spacer between EML/ETL, enabling the distribution of recombination zone away from this interface. Consequently, the optimized OLED exhibits a low driving voltage, promising device stability (95% of the initial luminance of 1000 cd m−2, LT95 > 430 h), and a high Commission Internationale de L’Éclairage y coordinate of 0.69. This indicates that managing the excitons through rational energy level alignment holds the potential for simultaneously satisfying Rec.2020 standard and achieving commercial-level stability.

Polysaccharide‐Modified SnO2 for Highly Efficient Perovskite Solar Cells

Tin oxide (SnO2) has been demonstrated as a promising electron transport material for perovskite solar cells (PSCs) due to its low‐temperature process and high charge extraction ability. However, the key to improving the internal performance of PSCs toward unity lies in the ability of enhancing bulk SnO2 quality and reducing the energy level mismatch between SnO2 and perovskite layer. Herein, a facile and effective strategy to simultaneously functionalize SnO2 structure by sodium alginate (SA) polysaccharide compound is reported. The investigations reveal that SA leads to the formation of nanosynapse structure of SnO2 films, which allows the aligned energy levels and suppressed charge recombination, significantly enhancing carrier extraction and transport. Consequently, CsMAFAPb(IxBr1−x)3 and CsPbI2Br solar cells achieve a remarkable power conversion efficiency of 24.11% and 16.90%, respectively, based on SnO2‐SA electron transport layers (ETLs). This work offers a facile and effective way to fabricate high‐performance SnO2 ETL in PSCs.

Studies of optoelectrical properties of Mn-doped ZnO nanostructure for supercapacitor and photodetector applications

The transition metal Manganese (Mn)-doped Zinc Oxide (ZnO) nanoparticles were synthesized using the sol-gel method. The nanomaterials ZnO and Zn1-xMnxO (x=0–0.15) formation, their crystal structure, and morphological properties were confirmed by X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) analysis of the materials. All the studied materials show hexagonal wurtzite structure with the particle size in nanometres. The optical properties of transition metal Mn-doped ZnO nanomaterials were explored by the absorption and transmission spectra. The band gap of the nanomaterials decreases with the increase of Mn doping concentration from 3.01 to 3.26 eV. The mobility and electrical conductivity of the Mn-doped ZnO thin films show a decreasing trend with the increase of Mn doping concentration in ZnO. The Mn-doped materials were investigated for supercapacitor and photodiode applications. The Zn0.90Mn0.10O nanomaterials show the maximum specific capacitance, power and energy density of ∼ 220 F/g, 2202 W/kg and 1.15 Wh/kg, respectively. The electrochemical properties confirm that the doping of ZnO opens a new window for its application in energy storage devices. The ZnO and Mn-doped ZnO were used as an electron transport layer in perovskite MAPbI3 photodiodes. Under the Illumination of blue (465 nm) light, the highest detectivity of undoped ZnO perovskite photodiode is ∼4.5×1010 Jones and doped ZnO perovskite photodiode is 0.7×1010 Jones, respectively. The low mobility of charges and unfavorable energy level alignment of Mn-doped ZnO with MAPbI3 thin films is the reason for the decrease in photo detectivity. Our studies demonstrate that the Mn-doped ZnO nanomaterials and their thin films have avenues for potential application in energy storage devices and photodiodes of perovskite MAPbI3.

Improving Thermal Stability of High-Efficiency Methylammonium-Free Perovskite Solar Cells via Chloride Additive Engineering.

Tin dioxide (SnO2), in perovskite solar cells (PSCs), stands out as the material most suited to the electron transport layer (ETL), yielding advantages with regard to ease of preparation, high mobility, and favorable energy level alignment. Nonetheless, there is a chance that energy losses from defects in the SnO2 and interface will result in a reduction in the Voc. Consequently, optimizing the interfaces within solar cell devices is a key to augmenting both the efficiency and the stability of PSCs. Herein this present study, we introduced butylammonium chloride (BACl) into the SnO2 ETL. The resulting optimized SnO2 film mitigated interface defect density, thereby improving charge extraction. The robust bonding capability of negatively charged Cl- ions facilitated their binding with noncoordinated Sn4+ ions, effectively passivating defects associated with oxygen vacancies and enhancing charge transport within the SnO2 ETL. Concurrently, doped BA+ and Cl- diffused into the perovskite lattice, fostering perovskite grain growth and reducing the defects in perovskite. In comparison to the control device, the Voc saw a 70 mV increase, achieving a champion efficiency of 22.86%. Additionally, following 1000 h of ambient storage, the unencapsulated device based on SnO2 preburied with BACl retained around 90% of its initial photovoltaic conversion efficiency.

19.36% Efficiency Organic Solar Cells Based on Low‐Cost Terpolymer Donors with Simple Molecular Structures

AbstractLow cost and high performance are key elements for the industrialization of organic solar cells (OSCs). In view of this, developing highly‐efficient organic photovoltaic molecules with simple chemical structure is one of the most effective countermeasures. Herein, three simple‐structure terpolymers PTQ12‐5, PTQ12‐10, and PTQ12‐15 are designed and synthesized, by embedding difluoro‐substituted bithiophene (2T‐2F) unit into the backbone of low‐cost and high‐efficiency polymer PTQ10. The synthesis of three terpolymers contains only two‐step synthetic routes and over 85% synthetic yields from cheap raw compounds, thus exhibiting distinctly low‐cost characteristic. Remarkably, PTQ12‐5 shows significantly higher absorbance coefficient and hole mobility than PTQ10. Consequently, PTQ12‐5‐based OSCs shows more efficient exciton dissociation and charge transfer, suppressed carrier recombination, tighter molecular π‐π stacking, and faster and more balanced charge transport, thus demonstrates a significantly improved efficiency of 18.77% than that of PTQ10‐based device (18.03%). Moreover, an outstanding efficiency of 19.36% is achieved in PTQ12‐5‐based ternary device by further modulating the energy level alignment and blending features of photoactive molecules, which is the highest efficiency of OSCs based on low‐cost polymers to date. This work has significant implications for guiding the design of low‐cost and high‐performance organic photovoltaic materials.

An Acceptor–Donor–Acceptor Molecule Tailored Versatile Buffer Enabling Efficient and Stable Perovskite Solar Cells

AbstractInterface in perovskite solar cells (PSCs) is of vital importance because it dominates deep‐level defects and non‐radiative recombination, thus impacting both efficiency and stability further. Herein, a symmetrical acceptor–donor–acceptor (A–D–A) conjugated molecule with the core architecture of terthieno[3,2‐b hiophene and 2‐(3‐oxo‐2,3‐dihydro‐1 H‐inden‐1‐ylidene)malononitrile, named 6TIC, as a versatile buffer layer, is adopted to enhance photovoltaic performance and stability simultaneously. It is found that the conjugated molecule filling at grain boundaries and surface can not only chemically anchor with perovskite components to substantially eliminate interfacial defects and suppress detestable non‐radiative recombination, but also effectively improve the energy level alignment and facilitate charge transfer efficiency at the interface, resulting in an excellent power conversion efficiency of 24.81% with an admirable fill factor of 84.5%. Furthermore, benefiting from the unexceptionable surface protection effect of the hydrophobic buffer layer, greatly improved operational stability is delivered, with retaining 90% of initial efficiency for 960 h aging in a relative humidity of 60 ± 5% air and 1450 h aging under continuous 85 °C heating stress. This strategy may provide a new avenue for advancing high‐efficiency and stable PSCs.

Improving Thermal Stability of Perovskite Solar Cells by Suppressing Ion Migration

Ion migration presents a formidable obstacle to the stability and performance of perovskite solar cells (PSCs), hindering their progress toward commercial feasibility. Herein, the degradation mechanism of PSCs caused by iodide ion migration, which leads to abnormal changes in photoluminescence transients at the buried interface of perovskite films, is investigated. In light of this problem, a novel strategy is proposed to mitigate ion migration by introducing poly(2‐vinylnaphthalene) into poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine] as the hole transport layer with improved ion‐blocking capability. Consequently, this layer effectively reduces defect concentration, suppresses ion migration, and modulates energy level alignment, leading to an impressive efficiency exceeding 23% for doctor‐bladed FAPbI3 PSCs. Moreover, the corresponding unencapsulated devices demonstrate remarkable durability, maintaining over 80% of their initial value after undergoing rigorous stress tests in accordance with the International Electrotechnical Commission 61215 standard for temperature, humidity, and illumination. These tests include 1000 h of thermal cycling and a long‐term operational test lasting 600 h under maximum power point tracking.

Bridging the buried interface with conjugated molecule for highly efficient carbon-based inorganic CsPbI2Br perovskite solar cells fabricated in air

Manipulating the buried interface of all-inorganic perovskite solar cells (PSCs) is essential to improve the performance of devices. However, the conventional modifiers of interface typically present insulating feature that can impede the transportation of carrier, leading to an inferior charge transport efficiency. Herein, we propose a conjugated molecule, 2,4-hexadienoic acid potassium salt, which can act as a bridge at the buried interface of device and improve the crystallization of perovskite film. Besides, this interfacial modifier also promotes larger and denser grains, passivating defects and suppress non-radiative recombination of buried interface. Simultaneously, the electrical performance of tin oxide film is enhanced and facilitate a better energy level alignment. Consequently, carbon electrodes-based PSCs (C-PSCs) are fabricated via a hot air-assisted method in air, and C-PSCs based on all-inorganic perovskite demonstrate significant enhancement of open circuit voltage (1.25 V) via conjugated molecule modification, and the power conversion efficiency (PCE) increase significantly from 10.86 % to 13.11 %. Moreover, unencapsulated target devices exhibit better stability than the control devices. This work offers a new idea to construct an interfacial bridge via conjugated molecule for efficient and stable C-PSCs fabricated in air.

Conjugated Polymer/Recombinant Escherichia coli Biohybrid Systems for Photobiocatalytic Hydrogen Production.

Biohybrid photocatalysts are composite materials that combine the efficient light-absorbing properties of synthetic materials with the highly evolved metabolic pathways and self-repair mechanisms of biological systems. Here, we show the potential of conjugated polymers as photosensitizers in biohybrid systems by combining a series of polymer nanoparticles with engineered Escherichia coli cells. Under simulated solar light irradiation, the biohybrid system consisting of fluorene/dibenzo [b,d]thiophene sulfone copolymer (LP41) and recombinant E. coli (i.e., a LP41/HydA BL21 biohybrid) shows a sacrificial hydrogen evolution rate of 3.442 mmol g-1 h-1 (normalized to polymer amount). It is over 30 times higher than the polymer photocatalyst alone (0.105 mmol g-1 h-1), while no detectable hydrogen was generated from the E. coli cells alone, demonstrating the strong synergy between the polymer nanoparticles and bacterial cells. The differences in the physical interactions between synthetic materials and microorganisms, as well as redox energy level alignment, elucidate the trends in photochemical activity. Our results suggest that organic semiconductors may offer advantages, such as solution processability, low toxicity, and more tunable surface interactions with the biological components over inorganic materials.

Efficient Large-Area (81 cm2) Ternary Copper Halides Light-Emitting Diodes with External Quantum Efficiency Exceeding 13% via Host-Guest Strategy.

Ternary copper (Cu) halides are promising candidates for replacing toxic lead halides in the field of perovskite light-emitting diodes (LEDs) toward practical applications. However, the electroluminescent performance of Cu halide-based LEDs remains a great challenge due to the presence of serious nonradiative recombination and inefficient charge transport in Cu halide emitters. Here, the rational design of host-guest [dppb]2Cu2I2 (dppb denotes 1,2-bis[diphenylphosphino]benzene) emitters and its utility in fabricating efficient Cu halide-based green LEDs that show a high external quantum efficiency (EQE) of 13.39% are reported. The host-guest [dppb]2Cu2I2 emitters with mCP (1,3-bis(N-carbazolyl)benzene) host demonstrate a significant improvement of carrier radiative recombination efficiency, with the photoluminescence quantum yield increased by nearly ten times, which is rooted in the efficient energy transfer and type-I energy level alignment between [dppb]2Cu2I2 and mCP. Moreover, the charge-transporting mCP host can raise the carrier mobility of [dppb]2Cu2I2 films, thereby enhancing the charge transport and recombination. More importantly, this strategy enables a large-area prototype LED with a record-breaking area up to 81 cm2, along with a decent EQE of 10.02% and uniform luminance. It is believed these results represent an encouraging stepping stone to bring Cu halide-based LEDs from the laboratory toward commercial lighting and display panels.

Efficient Charge Injection for Perovskite Light‐Emitting Transistor

AbstractMetal halide perovskite semiconductors have demonstrated remarkable performance in light‐emitting‐diode applications in recent years. However, their potential application in other emerging optoelectronic devices, such as light‐emitting field‐effect transistors (LEFETs) is impeded by poor luminous efficiency due to inefficient charge injection. Here, an n‐type MgZnInO (MIZO) as the channel layer is synthesized to achieve efficient electron injection in perovskite LEFETs. These findings indicate that the incorporation of Mg not only suppresses the generation of oxygen vacancies but also optimizes the energy level alignment. These synergistic effects reduce non‐radiative recombination and improve interfacial charge transport. Consequently, the MIZO‐based perovskite LEFETs exhibit an improvement in threshold voltage, subthreshold swing, and field‐effect mobility. The electroluminescence performance shows a peak external quantum efficiency (EQE) of 1.97% with a maximum brightness of 2.1 × 104 cd m−2, accompanied by low‐efficiency roll‐off (an EQE of 1.88% at the current density of 810 mA cm−2). To the best of the author's knowledge, this represents the best luminous efficiency reported for perovskite LEFETs to date.

The Key Role of Hole Transport Layer in Boosting Performance of Two‐Dimensional Perovskite Solar Cells

Although currently in the nascent stages of research and development, two‐dimensional perovskite solar cells have showcased remarkable promise as the robust and efficient solar cell technology. Anticipated progressions and refinements in this domain are poised to establish two‐dimensional perovskite cells as instrumental catalysts in shaping the trajectory of renewable energy, heralding transformative breakthroughs. The hole transport layer (HTL) plays an irreplaceable role in the charge carriers’ transport and interface effects in two‐dimensional perovskite devices. This review starts with the structural characteristics of two‐dimensional perovskite solar cells. The influence of the intrinsic characteristics of the perovskite active layer itself and the interaction of the perovskite/transport layer contact interface are analyzed. This discussion delves into the impact of intrinsic quantum confinement and the dielectric effect within the two‐dimensional perovskite structure on photovoltaic conversion efficiency. It also explores the energy level alignment between the clathrate active layer and the transport layer. The significance of the HTL is emphasized, particularly regarding crystalline control, phase distribution, and interface passivation. Additionally, the crucial role of efficient carrier transport between the active layer and the transport layer is thoroughly examined.

Dimensional and Doping Engineering of Chiral Perovskites with Enhanced Spin Selectivity for Green Emissive Spin Light-Emitting Diodes.

Chiral perovskites play a pivotal role in spintronics and optoelectronic systems attributed to their chiral-induced spin selectivity (CISS) effect. Specifically, they allow for spin-polarized charge transport in spin light-emitting diodes (LEDs), yielding circularly polarized electroluminescence at room temperature without external magnetic fields. However, chiral lead bromide-based perovskites have yet to achieve high-performance green emissive spin-LEDs, owing to limited CISS effects and charge transport. Herein, we employ dimensional regulation and Sn2+-doping to optimize chiral bromide-based perovskite architecture for green emissive spin-LEDs. The optimized (PEA)x(S/R-PRDA)2-xSn0.1Pb0.9Br4 chiral perovskite film exhibits an enhanced CISS effect, higher hole mobility, and better energy level alignment with the emissive layer. These improvements allow us to fabricate green emissive spin-LEDs with an external quantum efficiency (EQE) of 5.7% and an asymmetry factor |gCP-EL| of 1.1 × 10-3. This work highlights the importance of tailored perovskite architectures and doping strategies in advancing spintronics for optoelectronic applications.