Energy Alignment Research Articles

Self-Assembled Biomolecule Interlayer for Enhanced Efficiency and Stability of Inverted Organic Solar Cells

Interlayers play a vital role in achieving high efficiency and stability of organic solar cells (OSCs). Zinc oxide (ZnO) has been widely used as an electron transport layer (ETL) in inverted OSCs; however, its high structural defects and intrinsic photocatalytic nature toward nonfullerene acceptors limit its applications in OSCs. Herein, a low-cost, environmentally-friendly biomolecule, potassium aspartic acid (PAA), is introduced as the interlayer on top of the ZnO ETL. Through experimental results and theoretical calculations, we find PAA not only can tune energy alignments and passivate oxygen vacancy defects and zinc interstitial dangling bonds but also can promote the π–π stacking strength of the active layer, leading to enhanced charge collection and photovoltaic performance in both IT series (e.g., PM6:IT-4F) and Y series (e.g., PM6:BTP-4F-C5-16) OSCs. Moreover, benefiting from the reduced surface defects of ZnO, OSCs based upon the ZnO/PAA ETL exhibit superior stabilities under continuous operation as well as UV-light irradiation, leading to an improved T80 lifetime of around 4 times compared to OSCs fabricated without the PAA interlayer. This work provides a universal solution to fabricate efficient and stable inverted OSCs.

In-situ surface defects passivation with small carbon chain molecules for highly efficient, air-processed inorganic CsPbI2Br perovskite photovoltaics

All-inorganic CsPbI2Br perovskites have gained enormous interests owing to suitable band gap and thermal stability. However, the CsPbI2Br suffers from unsatisfactory crystal growth and poor surfaces processed under ambient conditions. Herein, we introduced small carbon chain molecules as liquid additives including diiodomethane (DIM), dibromoethane (DBM), and dichloromethane (DCM) into the precursor. The halide ions as associated with these additives played vital roles to passivate the surface defects. Interestingly, DIM additive offers multiple benefits: (i) passivate uncoordinated Pb2+ dangling bonds (ii) match band energy alignment, (iii) assist to preferential oriented crystal growth (iv) suppress halide ion vacancies and (v) improve surface morphology. As a result, 100 μl DIM-assisted perovskite solar cell (PSC) exhibited the highest power conversion efficiency (PCE) of 16.42 % which is higher than that of control (13.95 %). Notably, with additive engineering approach our champion PCE (16.42 %) is the highest to date under processing at ambient conditions. On the contrary to poor stability of control PSC (PCE drop of ∼ 50 %), the DIM assisted PSC retained ∼ 80 % of original PCE after aging for 600 hrs. Thus, our photovoltaic results demonstrated that the additive method could open an effective route for development of efficient and stable PSCs under ambient conditions.

Cinnamate-Functionalized Cellulose Nanocrystals as Interfacial Layers for Efficient and Stable Perovskite Solar Cells.

The poor interfacial contact and imperfections between the charge transport layer and perovskite film often result in carrier recombination, inefficient charge collection, and inferior stability of perovskite solar cells (PSCs). Therefore, interface engineering is quite crucial to achieve high-performance and stable PSCs. Here, we introduced a cinnamate-functionalized cellulose nanocrystals (Cin-CNCs) interfacial layer between SnO2 and perovskite active layer for enhancing carrier transport ability and crystal growth of perovskite, meanwhile endowing additional functional of long-term device stability against ultraviolet light. The enhancement of interfacial contact between SnO2 and perovskite layer and cascade energy alignment are realized, which is beneficial for obtaining the desirable perovskite film morphology, passivating the interfacial defects, and restraining charge recombination in the SnO2/perovskite interface. An efficiency as high as 23.18%, with an open-circuit voltage of 1.15 V and a significantly enhanced fill factor of 81.07%, is achieved. In addition, the unencapsulated PSCs maintain 75% of the initial PCE after aging for over 1500 h under 25 °C and 30% relative humidity, with better light-soaking stability. These results exhibit the vital role for Cin-CNCs in interfacial modification and constructing high-performance perovskite solar cells.

Performance Enhancement of Perovskite Quantum Dot Light-Emitting Diodes via Management of Hole Injection.

Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is widely used in optoelectronic devices due to its excellent hole current conductivity and suitable work function. However, imbalanced carrier injection in the PEDOT:PSS layer impedes obtaining high-performance perovskite light-emitting diodes (PeLEDs). In this work, a novel poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,40-(N-(p-butylphenyl))diphenylamine)] (TFB) is applied as the hole transport layers (HTLs) to facilitate the hole injection with cascade-like energy alignment between PEDOT:PSS and methylammonium lead tribromide (MAPbBr3) film. Our results indicate that the introduced TFB layer did not affect the surface morphology or lead to any additional surface defects of the perovskite film. Consequently, the optimal PeLEDs with TFB HTLs show a maximum current efficiency and external quantum efficiency (EQE) of 21.26 cd A-1 and 6.68%, respectively. Such EQE is 2.5 times higher than that of the control devices without TFB layers. This work provides a facile and robust route to optimize the device structure and improve the performance of PeLEDs.

Ethylene glycol-containing ammonium salt for developing highly compatible interfaces in perovskite solar cells

For achieving efficient and stable perovskite solar cells (PSCs), the interface between the perovskite absorber and charge transport material should be modulated to provide proper energy alignment, fast charge delivery, and suppressed charge recombination. In this study, a multifunctional interface modifier for PSCs was developed by the quaternization of trimethylamine with 1-bromo-2-(2-methoxyethoxy)ethane. This ethylene glycol-containing ammonium salt (EG) effectively passivates interfacial traps and induces dipoles on the surface of the perovskite, facilitating charge transfer/extraction at the perovskite/hole transport material (HTM) interface. Accordingly, after the interface modification with EG, the PSCs showed a high efficiency of over 24% with a representative doped SpiroOMeTAD HTM. Moreover, the EG modification was revealed to be highly compatibility with dopant-free HTMs, resulting in an improved efficiency of up to 22.01% in its corresponding photovoltaics compared to those of the control and conventional alkyl-based salt treatments (19.44% and 17.94%, respectively).

Nb-doped La0.6Sr0.4FeO3-δ as an electrolyte for intermediate-temperature solid oxide fuel cells.

It is one of the effective strategies to develop intermediate-temperature solid oxide fuel cells (IT-SOFCs) by looking for alternative electrolyte materials that can maintain or even improve current cell efficiencies while reducing operating temperature. In this study, by rationally introducing pentavalent Nb on the B-site of La0.6Sr0.4FeO3-δ (LSFO), a serial of novel perovskite La0.6Sr0.4Fe1-xNbxO3-δ (LSFNbx, x = 0.1, 0.2) with mixed electron-ion conduction is successfully prepared. The electrochemical mechanism and performance of the symmetrical IT-SOFCs with a single LSFNbx perovskite oxide as electrolyte are investigated. With the Nb doping, the structure stability of the LSFO is improved and the electronic conductivity decreases. La0.6Sr0.4Fe0.8Nb0.2O3-δ (LSFNb20) is the most promising electrolyte of the three candidates as it has the best performance (735 mW cm-2 at 550 °C in a dry H2/Air atmosphere) and no short-circuiting problem. The applied voltage-response current curves demonstrate that the interface between the Ni-Ni0.8Co0.15Al0.05LiO2-δ anode and LSFNb20 electrolyte can block electron conduction more efficiently and has a better promoting effect on protons, which is fundamentally due to the band energy alignment of the interface heterojunction. Our work highlights that LSFNb20 is a high-performance perovskite alternative to monolayer electrolytes.

Aggregation of Charge Acceptors on Nanocrystal Surfaces Alters Rates of Photoinduced Electron Transfer.

Semiconductor nanocrystals (NCs) interfaced with molecular ligands that function as charge and energy acceptors are an emerging platform for the design of light-harvesting, photon-upconverting, and photocatalytic materials. However, NC systems explored for these applications often feature high concentrations of bound acceptor ligands, which can lead to ligand-ligand interactions that may alter each system's ability to undergo charge and energy transfer. Here, we demonstrate that aggregation of acceptor ligands impacts the rate of photoinduced NC-to-ligand charge transfer between lead(II) sulfide (PbS) NCs and perylenediimide (PDI) electron acceptors. As the concentration of PDI acceptors is increased, we find the average electron transfer rate from PbS to PDI ligands decreases by nearly an order of magnitude. The electron transfer rate slowdown with increasing PDI concentration correlates strongly with the appearance of PDI aggregates in steady-state absorption spectra. Electronic structure calculations and molecular dynamics (MD) simulations suggest PDI aggregation slows the rate of electron transfer by reducing orbital overlap between PbS charge donors and PDI charge acceptors. While we find aggregation slows electron transfer in this system, the computational models we employ predict ligand aggregation could also be used to speed electron transfer by producing delocalized states that exhibit improved NC-molecule electronic coupling and energy alignment with NC conduction band states. Our results demonstrate that ligand aggregation can alter rates of photoinduced electron transfer between NCs and organic acceptor ligands and should be considered when designing hybrid NC:molecule systems for charge separation.

Cybersecurity Challenges and Needs in The Context of Digital Development in Zimbabwe

This research was on the cybersecurity challenges and needs of grassroot users of cyberspace in Zimbabwe. A qualitative research methodology was used and was guided by the Interpretivist philosophy. Judgmental sampling was used to select the participants in the study based on their knowledge on cybersecurity matters. The sample was drawn from people from Murewa District of Zimbabwe. A descriptive research design was used to answer the research questions. Both unstructured and structured interviews as well as observations were used to collect data on the cybersecurity needs and challenges of grassroot users of cyberspace. The findings revealed that the challenges that grassroot users are facing include identity theft, poor internet connectivity and infrastructure problems. The research also exposed the need for stronger physical security of ICT assets and cybersecurity legislation. The researcher recommended the use of solar systems as an alternative source of energy and continuous review and alignment of cybersecurity legislation in line with the changing cyber threat landscape.

Cathode Buffer Layer for Energy‐Level Matching and Interface Passivation

Perovskite solar cells (PSCs) have demonstrated high‐power conversion efficiency (PCE) and exhibit great application potential in photovoltaic systems. Generally, a typical PSC is accompanied with multiinterfaces; therefore, charge extraction and transport in PSCs are strongly affected by these interfaces. In fact, interfacial energy‐level mismatch of carrier transport layer and anode/cathode is also deeply limiting the electrical performance of PSCs. Herein, a low‐temperature‐processed indium tin oxide (ITO‐LT) cathode buffer layer is developed and used for optimizing the energy‐level alignment and suppressing defects at the electron transfer layer and cathode interface. It is revealed that a 3 nm ITO‐LT cathode buffer layer with an appropriate energy alignment and effective defect suppression could enhance interfacial charge transfer, resulting in a PCE of 21.13% in a planar PSC.

Study of normal deformed bands in light Lutetium isotopes

The projected shell model has been employed to study the energy levels and alignment frequencies of the normally deformed bands of light lutetium isotopes. Band head spins and configurations have been reproduced for all the positive parity bands of 161−165Lu isotopes and negative parity bands of 163Lu. The theoretical aligned angular momenta reasonably reproduced the observed backbends and their corresponding rotational frequencies for all the experimentally observed normally deformed bands. Moreover, I = 7/2− state is predicted as band head spin for negative parity yrast bands of 161,165Lu. The negative parity yrast bands of 161,165Lu are predicted to have 1π1h11/2[523]7/2− configuration. Further, the calculated B(E2) values of 165Lu show reasonable agreement with the available experimental data. The dip predicted in the B(E2) values may be interpreted due to the alignment of a pair of neutrons in the neutron 1i13/2 orbital of all yrast bands of 161−165Lu.

The Investigation of the Influence of a Cu2O Buffer Layer on Hole Transport Layers in MAPbI3-Based Perovskite Solar Cells.

The passivation engineering of the hole transport layer in perovskite solar cells (PSCs) has significantly decreased carrier accumulation and open circuit voltage (Voc) loss, as well as energy band mismatching, thus achieving the goal of high-power conversion efficiency. However, most devices incorporating organic/inorganic buffer layers suffer from poor stability and low efficiency. In this article, we have proposed an inorganic buffer layer of Cu2O, which has achieved high efficiency on lower work function metals and various frequently used hole transport layers (HTLs). Once the Cu2O buffer layer was applied to modify the Cu/PTAA interface, the device exhibited a high Voc of 1.20 V, a high FF of 75.92%, and an enhanced PCE of 22.49% versus a Voc of 1.12 V, FF of 69.16%, and PCE of 18.99% from the (PTAA/Cu) n-i-p structure. Our simulation showed that the application of a Cu2O buffer layer improved the interfacial contact and energy alignment, promoting the carrier transportation and reducing the charge accumulation. Furthermore, we optimized the combinations of the thicknesses of the Cu2O, the absorber layer, and PTAA to obtain the best performance for Cu-based perovskite solar cells. Eventually, we explored the effect of the defect density between the HTL/absorber interface and the absorber/ETL interface on the device and recommended the appropriate reference defect density for experimental research. This work provides guidance for improving the experimental efficiency and reducing the cost of perovskite solar cells.

Molecularly Functionalized SnO2 Films by Carboxylic Acids for High-Performance Perovskite Solar Cells

Metal oxides are commonly employed as electron transport layers (ETLs) for n-i-p perovskite solar cells (PSCs), but the presence of surface traps and their mismatched energy alignment with perovskites limits the corresponding device performance. Therefore, the interfacial modification of ETLs by functional molecules becomes an important strategy for tailoring the interfacial properties and facilitating an efficient charge extraction and transport in PSCs. However, an in-depth understanding of the influences of their molecular structures on the surface chemistry and electronic properties of ETLs is rarely discussed. Herein, three carboxylic acid-based molecules with different chemical structures were employed to modify the SnO2 ETL and their effects on the performance of PSCs were systematically investigated. We found that the alkyl-chain length and carboxyl number in molecular structures can dramatically alter their binding strength to SnO2, providing a good strategy to fine-tune their film quality, electron mobility, and energy offset at the cathode interface. Benefiting from the optimal coordination ability of citric acid (CA) to SnO2, the corresponding PSCs show better charge transport properties and suppressed nonradiative recombination, leading to a champion efficiency of 23.1% with much improved environmental stability, highlighting the potential of rational design of molecular modifiers for high-performance ETLs applied in PSCs.

Lewis Acid-Base Adducts for Efficient and Stable Cesium-Based Lead Iodide-Rich Perovskite Solar Cells.

All-inorganic cesium-lead-iodide (CsPbI3 Br3- x (2 < x< 3)) perovskite presents preeminent photovoltaic performance and chemical stability. Unfortunately, this kind of material suffers from phase transition to a nonperovskite phase under oxidative chemical stresses. Herein, the introduction of a low concentration of Lewis acid-base adducts (LABAs) is reported to synergistically reduce defect density, optimize interfacial energy alignment, and improve device stability of CsPbI2.75 Br0.24 Cl0.01 (CsPbTh3 ) solar cells. Both theoretical simulations and experimental measurements reveal that the noncoordinating anions, PF6 - , as a Lewis base can more effectively bind with undercoordinated Pb2+ to passivate iodide vacancy defects than the BF4 - and absorbed I- , and thus the point defects are well suppressed. In addition, N-propyl-methyl piperidinium (NPMP+ ) is selected to assemble with PF6 - in CsPbTh3 film. The NPMP+ can regulate the crystal growth and finally homogenize the grain size and decrease the trap density. Consequently, the LABAs strategy can improve the power conversion efficiency of CsPbTh3 solar cells to 19.02% under 1-sun illumination (100mW cm-2 ). Fortunately, the NPMP+ and PF6 - -treated CsPbTh3 film shows great phase stability after storage in ambient air for 250 days, and the power conversion efficiency of corresponding solar cells is almost 76% of the initial value after 60 days aging under ambient conditions.

Nondestructive Post-Treatment Enabled by In Situ Generated 2D Perovskites Derived from Multi-ammonium Molecule Vapor for High-Performance 2D/3D Bilayer Perovskite Solar Cells.

Recently, two-dimensional (2D)/three-dimensional (3D) bilayer perovskite solar cells (PSCs) show a great potential for commercialization due to the combination of the fascinating photovoltaic performance of 3D perovskites and superior stability of 2D perovskites. However, it is a challenge to nondestructively construct 2D/3D bilayer perovskites, and the impact of the number of amine groups in ammonium spacer cations on the properties of 2D/3D bilayer perovskites has not been investigated. In this work, a novel interfacial post-treatment strategy is proposed to nondestructively fabricate 2D/3D bilayer perovskite films using the multi-ammonium molecule (MAM) vapor. Here, a series of MAMs with three to six amine groups (3 to 6N), including diethylenetriamine (DETA, 3N), triethylenetetramine (TETA, 4N), tetraethylenepentamine (TEPA, 5N), and pentaethylenehexamine (PEHA, 6N), are applied and compared. Benefiting from the strong interaction between MAMs and perovskites, the MAM vapor post-treatment can in situ generate Dion-Jacobson (DJ) 2D capping layers on the surface of 3D perovskite films. In comparison with the 3D perovskite film, such DJ 2D/3D perovskite films exhibit improved film quality, effectively passivated defects/traps, optimized interfacial band energy alignment, and mitigatory tensile strain. In particular, the number of amine groups in MAMs can dramatically influence the quality of DJ 2D/3D bilayer perovskite films and their corresponding photovoltaic performance. As the number of amine groups increases from DETA to PEHA, the efficiency and stability of PSCs are boosted significantly. Consequently, the PEHA-based DJ 2D/3D bilayer PSC delivers a champion power conversion efficiency of 21.79% with a negligible hysteresis effect, elevated reproducibility, and enhanced device stability. This work offers the reference for designing novel and effective MAMs for nondestructively fabricating high-performance 2D/3D bilayer PSCs.

Highly Efficient and Stable FASnI3 Perovskite Solar Cell via Modification with Tetrapotassium Hexacyanoferrate

Sn‐based perovskite material is one of the promising absorption materials due to its low toxicity and narrow bandgap. However, the unsatisfying quality of the perovskite film caused by Sn2+ oxidation and poor crystal growth greatly hinders the device performance. Herein, a layer of tetrapotassium hexacyanoferrate at the PEDOT:PSS/FASnI3 interface is introduced, which can minimize the concentration of Sn4+, thereby suppressing the defect states in the perovskite film, enhancing the conductivity of the PEDOT:PSS film, and forming well‐matched energy alignment in the device. Consequently, the champion device performance of 8.9% is obtained by the modified device, and the unencapsulated device can keep outstanding stability in N2 atmosphere.

Excitonic Effects in X-ray Absorption Spectra of Fluoride Salts and Their Surfaces

Given their natural abundance and thermodynamic stability, fluoride salts may appear as evolving components of electrochemical interfaces in Li-ion batteries and emergent multivalent ion cells. This is due to the practice of employing electrolytes with fluorine-containing species (salt, solvent, or additives) that electrochemically decompose and deposit on the electrodes. Operando X-ray absorption spectroscopy (XAS) can probe the electrode–electrolyte interface with a single-digit nanometer depth resolution and offers a wealth of insights into the evolution and Coulombic efficiency or degradation of prototype cells, provided that the spectra can be reliably interpreted in terms of local oxidation state, atomic coordination, and electronic structure about the excited atoms. To this end, we explore fluorine K-edge XAS of mono- (Li, Na, and K) and di-valent (Mg, Ca, and Zn) fluoride salts from a theoretical standpoint and discover a surprising level of detailed electronic structure information about these materials despite the relatively predictable oxidation state and ionicity of the fluoride anion and the metal cation. Utilizing a recently developed many-body approach based on the ΔSCF method, we calculate the XAS using density functional theory and experimental spectral profiles are well reproduced despite some experimental discrepancies in energy alignment within the literature, which we can correct for in our simulations. We outline a general methodology to explain shifts in the main XAS peak energies in terms of a simple exciton model and explain line-shape differences resulting from the mixing of core-excited states with metal d character (for K and Ca specifically). Given ultimate applications to evolving interfaces, some understanding of the role of surfaces and their terminations in defining new spectral features is provided to indicate the sensitivity of such measurements to changes in interfacial chemistry.

Edge carboxylation-induced charge separation dynamics of graphene quantum dot/cellulose nanocomposites

Graphene quantum dot (GQD)@cellulose nanocomposites possess optoelectronic properties of interest for photovoltaic applications. However, the optoelectronic properties related to the shapes and edge types of GQDs have not been fully explored. In the present work, we investigate the effects of carboxylation on the energy alignment and charge separation dynamics at the interface of GQD@cellulose nanocomposites using density functional theory calculations. Our results show that the GQD@cellulose nanocomposites composed of hexagonal GQDs with armchair edges exhibit better photoelectric performance than those composed of other types of GQDs. Carboxylation stabilizes the energy level of the highest occupied molecular orbital (HOMO) of the triangular GQDs with armchair edges but destabilizes the HOMO energy level of cellulose, resulting in hole transfer from the GQDs to cellulose upon photoexcitation. However, the calculated hole transfer rate is lower than the nonradiative recombination rate because excitonic effects dominate the dynamics of charge separation in GQD@cellulose nanocomposites.

Semiconductor Halogenation in Molecular Highly‐Oriented Layered p–n (n–p) Junctions

AbstractOrganic p–n junctions attract widespread interest in the field of molecular electronics because of their unique optoelectronic singularities. Importantly, the molecular donor/acceptor character is strongly correlated to the degree of substitution, e.g., the introduction of electron‐withdrawing groups. Herein, by gradually increasing the degree of peripheral fluorination on planar, D4h−symmetric iron(II) phthalocyanato (FePc) complexes, the energy level alignment and molecular order is defined in a metal‐supported bilayered Pc‐based junction using photoemission orbital tomography. This non‐destructive method selectively allows identifying molecular levels of the hetero‐architectures. It demonstrates that, while the symmetric fluorination of FePc does not disrupt the long‐range order and degree of metal‐to‐molecule charge transfer in the first molecular layer, it strongly impacts the energy alignment in both the interface and topmost layer in the bilayered structures. The p–n junction formed in the bilayer of perhydrogenated FePc and perfluorinated FeF16Pc may serve as an ideal model for understanding the basic charge‐transport phenomena at the metal‐supported organic–organic interfaces, with possible application in photovoltaic devices.

Electrochemically controlled rectification in symmetric single-molecule junctions

Single-molecule electrochemical science has advanced over the past decades and now extends well beyond molecular imaging, to molecular electronics functions such as rectification and amplification. Rectification is conceptually the simplest but has involved mostly challenging chemical synthesis of asymmetric molecular structures or asymmetric materials and geometry of the two enclosing electrodes. Here we propose an experimental and theoretical strategy for building and tuning in situ (in operando) rectification in two symmetric molecular structures in electrochemical environment. The molecules were designed to conduct electronically via either their lowest unoccupied molecular orbital (LUMO; electron transfer) or highest occupied molecular orbital (HOMO; "hole transfer"). We used a bipotentiostat to control separately the electrochemical potential of the tip and substrate electrodes of an electrochemical scanning tunneling microscope (EC-STM), which leads to independent energy alignment of the STM tip, the molecule, and the STM substrate. By creating an asymmetric energy alignment, we observed single-molecule rectification of each molecule within a voltage range of ±0.5 V. By varying both the dominating charge transporting LUMO or HOMO energy and the electrolyte concentration, we achieved tuning of the polarity as well as the amplitude of the rectification. We have extended an earlier proposed theory that predicts electrolyte-controlled rectification to rationalize all the observed in situ rectification features and found excellent agreement between theory and experiments. Our study thus offers a way toward building controllable single-molecule rectifying devices without involving asymmetric molecular structures.

Efficient Perovskite Indoor Photovoltaics with Open-Circuit Voltage of 1.15V via Collaborative Optimization of CsPbI2 Br Layer and Hole Transport Layer.

All-inorganic CsPbI2 Br perovskite has attracted great attention due to the stable crystal structure and moisture resistance, and its 1.91eV bandgap is close to the optimal bandgap of indoor artificial light sources, making it be the best candidate for the indoor photovoltaics (IPVs) to power a wide range of internet of things related electronic devices. Herein, we report on the preparation of CsPbI2 Br with α-phase and the improvement of its phase stability by adding lead acetate in the CsPbI2 Br precursor. A series of dopant-free conjugated polymers (P3HT, PBDB-T, and PM6) with different highest occupied molecular orbital energy levels are introduced as hole transport layers for building IPV devices. The PM6 based devices having better energy alignment with perovskite demonstrate best indoor photovoltaic performance, giving a remarkable open-circuit voltage of 1.15V and high fill factor of 81.86% under 1000 lux (330 µW cm-2 ) light-emitting diode illumination, and finally realizing a decent power conversion efficiency of 33.68%. Our findings suggest that collaboratively optimize the CsPbI2 Br layer and hole transport layer is an effective approach to realize high performance IPVs.