Inorganic Perovskite Solar Cells Research Articles

Numerical Simulation of All Inorganic CsPbIBr2 Perovskite Solar Cells with Diverse Charge Transport Layers using DFT and SCAPS-1D Frameworks

Numerical Simulation of All Inorganic CsPbIBr2 Perovskite Solar Cells with Diverse Charge Transport Layers using DFT and SCAPS-1D Frameworks

Ambient Air Processed Inverted Inorganic Perovskite Solar Cells with over 21 % Efficiency Enabled by Multifunctional Ethacridine Lactate

AbstractAll‐inorganic cesium lead triiodide perovskites (CsPbI3) have attracted increasing attention due to their good thermal stability, remarkable optoelectronic properties, and adaptability in tandem solar cells. However, N2‐filled glovebox is generally required to strictly control the humidity during film fabrication due to the moisture‐induced black‐to‐yellow phase transition, which remains a great hinderance for further commercialization. Herein, we report an effective approach via incorporating multifunctional ethacridine lactate (EAL) to mitigate moisture invasion and enable the fabrication of efficient inverted (p‐i‐n) CsPbI3 perovskite solar cells (PSCs) under ambient condition. It is revealed that the lactate anions accelerate the crystallization of CsPbI3, shortening the exposure time to moisture during film fabrication. Meanwhile, the conjugated backbone and multiple functional groups in the ethacridine cations can interact with I− and Pb2+ to reduce the undesired defects, stabilize the perovskite structure and facilitate the charge transport in the film. Moreover, EAL incorporation also leads to better energy alignment, thus favoring charge extraction at both upper and bottom interfaces. Consequently, the device efficiency and stability are enormously enhanced, with the champion efficiency reaching 21.08 %. This even surpasses the highest value reported for the devices fabricated in glovebox, representing a record efficiency of inverted all‐inorganic PSCs.

Effect of Pb-site doping on the structure, electronic and mechanical properties of CsPbI3 perovskite: A first-principles study

CsPbI3 has received a great deal of attention as the light-harvesting component of pure inorganic perovskite solar cells (PSCs). It is revealed that Pb-site doping is an effective way to enhance the electrical and optical properties of CsPbI3 compared with other methods. In this study, within the framework of the density functional theory (DFT), first-principles method was used to investigate different Pb-site ionic doping effect on the structural, mechanical, electrical, and optical properties of CsPbI3. We considered totally 11 doping elements, each with a doping concentration of 12.5 % (denoted as CsPb0.875M0.125I3, M is the doping element). The results revealed that all the doping systems are structurally stable with decreased bandgap values compared with the pristine CsPbI3. CsPb0.875M0.125I3 (M=Ge, Sn) exhibits similar behavior to CsPbI3, while CsPb0.875M0.125I3 (M= As, Sb, Bi) series present electron-doping character and CsPb0.875M0.125I3 (M=Ga, In, Tl) shows hole-doping effect. Mechanically, all the other elements mono-doped CsPbI3 satisfy the stability requirement except CsPb0.875Ga0.125I3. Moreover, most of doping systems show enhanced the absorption strength in the visible light region. By synthetically considering the mechanical, electronic and optical properties, it is suggested that CsPb0.875M0.125I3 (M=Sb, Fe) exhibit relatively superior characteristics compared with pristine and other elements mono-doped CsPbI3. Results obtained in the present work may provide valuable guidance for the synthesis and the performance refinement of all-inorganic CsPbI3-based PSCs in the future.

Inhibited superoxide‐induced halide oxidation with a bioactive factor for stabilized inorganic perovskite solar cells

Inhibited superoxide‐induced halide oxidation with a bioactive factor for stabilized inorganic perovskite solar cells

Customizing Aniline-Derived Molecular Structures to Attain beyond 22% Efficient Inorganic Perovskite Solar Cells.

The characteristics of the soft component and the ionic-electronic nature in all-inorganic CsPbI3-xBrxperovskite typically lead to a significant number of halide vacancy defects and ions migration, resulting in a reduction in both photovoltaic efficiency and stability. Herein, we present a tailored approach in which both anion-fixation and undercoordinated-Pb passivation are achieved in situ during crystallization by employing a molecule derived from aniline, specifically 2-methoxy-5-trifluoromethylaniline (MFA), to address the above challenges. The incorporation of MFA into the perovskite film results in a pronounced inhibition of ion migration, a significant reduction in trap density, an enhancement in grain size, an extension of charge carrier lifetime, and a more favorable alignment of energy levels. These advantageous characteristics contribute to achieving a champion power conversion efficiency (PCE) of 22.14% for the MFA-based CsPbI3-xBrx perovskite solar cells (PSCs), representing the highest efficiency reported thus far for this type of inorganic metal halide perovskite solar cells, to the best of our knowledge. Moreover, the resultant PSCs exhibits higher environmental stability and photostability. This strategy is anticipated to offer significant advantages for large-area fabrication, particularly in terms of simplicity.

Customizing Aniline‐Derived Molecular Structures to Attain beyond 22% Efficient Inorganic Perovskite Solar Cells

Customizing Aniline‐Derived Molecular Structures to Attain beyond 22% Efficient Inorganic Perovskite Solar Cells

Target therapy at buried interfaces toward efficient and stable inorganic perovskite solar cells

The enhancement of power conversion efficiency (PCE) of perovskite solar cells (PSCs) is critically affected by charge recombination induced by buried interface defects. In light of this, a simple and effective target therapy strategy has been developed by doping 4-(diphenylphosphino)benzoic acid (4DBA) molecules at the tin oxide (SnO2)/perovskite interface. The effects of 4DBA on carrier transport, perovskite growth, defect passivation, and PSCs properties were systematically investigated. It is illustrated that 4DBA molecules not only passivate oxygen vacancy (OV) defects on the SnO2 surface, enhancing the conductivity of the SnO2 film and accelerating electron transfer, but also passivate perovskite interface defects, thereby improving the quality of the perovskite film. Ultimately, the efficiency of CsPbBr3 device with 4DBA-modified buried interface increased from 8.87% to 10.78%, an improvement of 21.53%. Furthermore, the efficiency of CsPbI2Br increased from 12.83% to 14.44%, an improvement of 12.55%, further demonstrating the effectiveness and universality of this strategy. Excitingly, the unencapsulated PSCs exhibit excellent long-term stability under high relative humidity and high temperatures.

In Situ Dehydration Condensation of Self‐Assembled Molecules Enables Stabilization of CsPbI3 Perovskites for Efficient Photovoltaics

AbstractInorganic perovskites, with Cs+ substituting volatile organic components, show great promise in photovoltaic applications due to their outstanding optoelectronic properties and thermal stability. However, the black‐to‐yellow phase transition of CsPbI3 remains a challenge for realizing high‐performance inorganic perovskite solar cells (IPSCs). Herein, an effective approach is reported via incorporating the self‐assembled molecule Me‐4PACz to synergistically stabilize the [PbI6]4− octahedra and form a hydrophobic layer at interface and grain boundaries. An in situ dehydration condensation reaction of Me‐4PACz is observed during film annealing, which favors the reduction of undesired aggregation of Me‐4PACz in humid air, thus leading to enhanced anchoring interaction and more effective hydrophobic protection of CsPbI3. Therefore, the air‐processed CsPbI3 perovskite films show dramatically improved phase purity and humid stability. This strategy also improves the energy level alignment between perovskite and charge transport layers. As a result, a champion efficiency of 20.21% is realized, representing one of the highest reported values for air‐processed inverted IPSCs. Furthermore, it is demonstrated that by combining Me‐4PACz with the previously reported ethacridine lactate (EAL) additive, the device performance can be further boosted to 21.38%, which is a record efficiency for the inverted IPSCs reported to date.

Enhancing Pb-free inorganic perovskite solar cell using carbon as metal back contact and molybdenum trioxide as hole transport layer

Inorganic Pb-free perovskite solar cells have appeared in recent years as a promising and environmentally friendly technology in photovoltaics. In this study, we conducted a comprehensive simulation investigation using SCAPS-1D software to optimize Pb-free inorganic perovskite solar cells, focusing specifically on the use of RbGeI3 as the absorber material in the FTO/TiO2/RbGeI3/MoO3/C device architecture. The carbon back contact in this configuration stands out for its cost-effectiveness and durability. Our research focused on the influence of various critical parameters, including the thickness of the absorber, electron affinity of ETL and HTL, series, and shunt resistances, back-contact material work functions, and operating temperatures. This achieved a PCE of 29.47 %, FF of 78.22 %, VOC of 1.111 V and JSC of 33.91 mA/cm2. The results indicate that perovskite solar cells using RbGeI3 as an absorber material exhibit improved performance and good thermal stability, underlining the great potential of this material. In addition, the eco-friendly characteristics of these Pb-free inorganic perovskite solar cells hold great promise for advancing the field of clean energy conversion technologies, marking an important step towards sustainable and efficient energy solutions.

Design and optimization of all-inorganic lead-free perovskite solar cells with RbGeI3/KSnI3 heterojunction structure

Currently, the performance of inorganic and non-toxic perovskite solar cells (PSCs) lags far behind that of organic and Pb-containing PSCs. To enhance the photovoltaic capabilities of inorganic and non-toxic perovskites, a fully inorganic RbGeI3/KSnI3 heterojunction without hole transport layer is proposed, and simulation and optimization are performed using SCAPS-1D software. Research findings indicate that the RbGeI3/KSnI3 perovskite heterojunction significantly improves the quantum efficiency compared to single-layer perovskite, and due to the more matched energy levels, it improves the electric field of the cell and is more conducive to the migration of photogenerated carriers, resulting in excellent device performance. Moreover, PSCs undergo optimization across multiple parameters, including materials for the charge transport layer, perovskite layer thickness, defect density, bandgap, operating temperature, and so on. This comprehensive approach involves analyzing changes in electric field, band structure, and recombination rate. Finally, the power conversion efficiency of the optimized device achieves 40.44 %, marking a significant 440 % increase compared to the 7.49 % efficiency of single-layer PSCs. This work proposes a heterojunction structure to create efficient inorganic and non-toxic perovskite solar cells, providing a novel strategy for further development in this field.

Performance enhancement of inorganic Cs2AgInBr6-based perovskite solar cell by numerical simulation

Performance enhancement of inorganic Cs2AgInBr6-based perovskite solar cell by numerical simulation

Reducing oxygen vacancies of MoO3 by polyaniline functionalization for stable and efficient inorganic tri-brominated perovskite solar cells

The photovoltaic performance of perovskite solar cells (PSCs) is closely dependent on the efficient carrier extraction and transport at the interface. Here, a polyaniline (PANI) functionalized MoO3 (PANI/MoO3) hole transport material (HTM) is exploited to perfect the interface between the perovskite layer and carbon electrode in all-inorganic CsPbBr3 PSCs. After functionalization with PANI, the p-type behavior and the hole mobility and conductivity of MoO3 are improved by reducing the oxygen vacancies, which boosts the hole extraction and transport, energy level arrangement at the interface of CsPbBr3 perovskite/(PANI/MoO3) HTM. Meanwhile, the PANI/MoO3 with rich C-N and N-H groups introduced by PANI passivates the ions trap states of perovskite films by the C-N···Pb2+ (Cs+) Lewis acid-base coordination and the N-H···Br- hydrogen bonding, leading to an effective suppression of non-radiative recombination for improved carrier extraction. As a result, the PANI/MoO3 HTMs-based CsPbBr3 PSCs obtain a remarkably increased power conversion efficiency of 10.41%, in comparison with the efficiency of the original device (6.55%). In addition, the unencapsulated device with PANI/MoO3 HTMs shows excellent long-term stability with 93.9% maintenance of the initial efficiency after storing in air with 85% relative humidity and at 85 °C for 30 days.

Effective surface treatment for efficient and stable inverted inorganic CsPbI2Br perovskite solar cells

The interest in all-inorganic perovskite solar cells (PSCs) featuring a p-i-n structure is on the rise, attributed to their superior heat resistance and adaptability with tandem cell methods. However, their progress has been far from the regular structure owing to the comparatively low open circuit voltage (Voc). This research employs phenylethylammonium iodide, incorporating various side groups, as passivators to tackle the previously mentioned problems and investigate their effects on passivation. It is found that a reduction of trap-state density in perovskite film was accomplished due to the PEAI effective passivation effect by establishing coordination with the under-coordinated Pb2+ ions. Furthermore, there was an enhancement in the alignment of energy levels at the CsPbI2Br perovskite/PCBM junction, resulting in better charge extraction from the CsPbI2Br layer to the charge transport layer. As a result, an improved champion efficiency of 14.26 % with a Voc of 1.11 V, Jsc of 16.21 mA/cm2, and FF of 79.28 % was yielded for the PEAI treatment inverted CsPbI2Br device, compared with the 12.15 % efficiency of the control device. Superior device stability was exhibited for the optimal PEAI-treated devices without encapsulation. This research validates the significance of a side group on a surface passivation molecule to effectively passivate defects and optimize energy levels, especially for boosting Voc.

Additive engineering by dicyandiamide for high-performance carbon-based inorganic perovskite solar cells

Hole transport layer (HTL)-free, all-inorganic CsPbIxBr3-x carbon-based perovskite solar cells (C-PSCs) have attracted much attention due to their low cost and excellent stability. The poor device efficiency is a barrier to constrain its commercialization, mainly due to the large amount of interfacial and bulk defects existed in inorganic perovskite films. In this study, an organic small molecule dicyandiamide (DCD) is added to the perovskite precursor as an additive to adjust the crystallization kinetics and passivate defects of inorganic perovskite films, simultaneously. It is demonstrated that the introduction of DCD can not only accelerate the transition process from intermediate-phase DMAPbI3 to inorganic perovskite, but also passivate defects through the Lewis acid-base interaction between cyano (CN), imine (CN) groups, and uncoordinated Pb2+. Meanwhile, the energy level alignment was optimized, which effectively improves the charge transport efficiency of CsPbIxBr3-x C-PSCs. As a result, optimized device shows an enhanced efficiency from 14.07% to 15.84%, accompanied by improved long-term stability.

Ambient Air Processed Inverted Inorganic Perovskite Solar Cells with over 21 % Efficiency Enabled by Multifunctional Ethacridine Lactate.

All-inorganic cesium lead triiodide perovskites (CsPbI3) have attracted increasing attention due to their good thermal stability, remarkable optoelectronic properties, and adaptability in tandem solar cells. However, N2-filled glovebox is generally required to strictly control the humidity during film fabrication due to the moisture-induced black-to-yellow phase transition, which remains a great hinderance for further commercialization. Herein, we report an effective approach via incorporating multifunctional ethacridine lactate (EAL) to mitigate moisture invasion and enable the fabrication of efficient inverted (p-i-n) CsPbI3 perovskite solar cells (PSCs) under ambient condition. It is revealed that the lactate anions accelerate the crystallization of CsPbI3, shortening the exposure time to moisture during film fabrication. Meanwhile, the conjugated backbone and multiple functional groups in the ethacridine cations can interact with I- and Pb2+ to reduce the undesired defects, stabilize the perovskite structure and facilitate the charge transport in the film. Moreover, EAL incorporation also leads to better energy alignment, thus favoring charge extraction at both upper and bottom interfaces. Consequently, the device efficiency and stability are enormously enhanced, with the champion efficiency reaching 21.08 %. This even surpasses the highest value reported for the devices fabricated in glovebox, representing a record efficiency of inverted all-inorganic PSCs.

Screening of Functional Small Molecules via Modified Machine Learning Strategy toward Efficient All-Inorganic Perovskite Solar Cells.

Organic small molecules are proven to be capable of passivating the bulk/interfacial defects in inorganic perovskite solar cells. Considering the burdensome situation to screen the functional small molecules, we employ a modified machine learning (ML) strategy to guide screening suitable small molecules toward efficient solar cells through three modified ML algorithms to construct the prediction model: (i) random forest algorithm (RF), (ii) support vector machine algorithm (SVR), and (iii) XGBoost. Among them, the XGBoost algorithm displays a better overall predictive performance, whereby the R2 index reaches 0.939. Accordingly, eight small molecules are selected to modify the interface of perovskite films, and both the theoretical and experimental results certify that the difluorobenzylamine with additional fluorine atoms has a better interface modification effect among the small molecules containing functional groups, e.g., the benzene ring and amino group. The high accuracy of the modified machine learning model enables us to simplify the small-molecule screening process and form an important step for ongoing developments in perovskite solar cells and other optoelectronic devices.

Non-destructive buffer enabling near-infrared-transparent inverted inorganic perovskite solar cells toward 1400 h light-soaking stable perovskite/Cu(In,Ga)Se2 tandem solar cells

Near-infrared (NIR) transparent inverted all-inorganic perovskite solar cells (PSCs) are excellent top cell candidates in tandem applications. An essential challenge is the replacement of metal contacts with transparent conductive oxide (TCO) electrodes, which requires the introduction of a buffer layer to prevent sputtering damage. In this study, we show that the conventional buffers (i.e., small organic molecules and atomic layer deposited metal oxides) used for organic-inorganic hybrid perovskites are not applicable to all-inorganic perovskites, due to non-uniform coverage of the vulnerable layers underneath, deterioration upon ion bombardment and moisture induced perovskite phase transition. A thin film of metal oxide nanoparticles by the spin-coating method serves as a non-destructive buffer layer for inorganic PSCs. All-inorganic inverted near-infrared-transparent PSCs deliver a PCE of 17.46% and an average transmittance of 73.7% between 780 and 1200 nm. In combination with an 18.56% Cu(In,Ga)Se2 bottom cell, we further demonstrate the first all-inorganic perovskite/CIGS 4-T tandem solar cell with a PCE of 24.75%, which exhibits excellent illumination stability by maintaining 86.7% of its initial efficiency after 1400 h. The non-destructive buffer lays the foundation for efficient and stable NIR-transparent inverted inorganic perovskite solar cells and perovskite-based tandems.

A novel investigation into strain-induced changes in the physical properties and solar cell performances of lead-free Ca3NCl3 perovskite

The first-principle calculations were employed to analyze the structural, thermodynamic, electronic, optical, and mechanical properties of calcium-based halide perovskites, Ca3NCl3, under pressure variations from +6 % to −6%. The Ca3NCl3 materials are thermodynamically and dynamically stable, as indicated by the negative final enthalpy values obtained under pressures ranging from −6% to +6 %. The charge density maps confirm the existence of both ionic and covalent bonding features. The unstressed Ca3NCl3 has a direct bandgap of 1.66 eV with PBE functions, 2.32 eV with HSE functions and 1.48 eV with spin-orbit coupling (SOC) at the Γ point. When subjected to compressive strain, the bandgap reduces to 1.37 eV(PBE), 1.93 eV(HSE) and 1.08 eV(SOC) at −6% strain, causing a redshift in absorption coefficient peaks. Conversely, under tensile strain, the bandgap slightly rises to 1.92 eV(PBE), 2.60 eV(HSE) and 1.73 eV(SOC) at +6 % strain, resulting in a blueshift in absorption coefficient peaks. The Ca3NCl3 materials show enhanced optical absorption, loss function, conductivity, dielectric function, refractive index and reflectivity under applied pressure, making them more appropriate for use in solar absorbers, surgical tools, and optoelectronic devices. The investigation of the mechanical properties reveals that the Ca3NCl3 perovskite is mechanically stable. Moreover, with rising pressure (tensile to compressive), elastic constants, elastic moduli, ductility, machinability index, bulk modulus, shear modulus, pugh's ratio, young modulus and anisotropy all rise. The photovoltaic (PV) performance of novel cell configurations, featuring Ca3NCl3 as an absorber and CdS as an Electron Transport Layer (ETL), was systematically studied using the SCAPS-1D simulator. This structure achieved a maximum power conversion efficiency (PCE) of 20.88 %, with a current density (JSC) of 19.184 mAcm−2, a voltage (VOC) of 1.22 V, and a fill factor (FF) of 89.06. The valuable findings from our simulations will aid in the experimental design of an efficient Ca3NCl3-based new inorganic perovskite solar cell in the near future.

Numerical investigation of the novel lead-free and eco-friendly InSnCl3-based inorganic perovskite solar cell using SCAPS-1D device simulation

Numerical investigation of the novel lead-free and eco-friendly InSnCl3-based inorganic perovskite solar cell using SCAPS-1D device simulation

In-Situ Self-Assembly Dipole Shielding Layer Toward Efficient and Stable Inorganic Perovskite Solar Cells.

Despite CsPbI2.75Br0.25inorganic perovskites exhibit high potential for single-junction and/or tandem solar cells, unexpected non-radiative recombination, and mismatched interfacial band alignment within the inorganic perovskite solar cells (PSCs) disadvantageously affect their photovoltaic performance. Rational design of the dipole shielding layer (DSL) is vital to realize a win-win situation for the defect passivation and band alignment. Herein, A-site dipole molecules, that is, neopentylamine and 2-methylbutylamine, are employed for in-situ self-assembly of a thus-far unreported DSL at the interface between 3D perovskite and hole transport layer. The as-prepared DSL demonstrates a 2D RP phase perovskite and the lattice-matching structurally-stable DSL@3D perovskite enables to alleviate the unexpected surface defects and suppress the spontaneous non-radiative recombination by means of effectively tuning the surface work function via regulating the dipole moment length and Van der Waals gap. Accordingly, the top dipole-modified inorganic PSCs exhibit a champion power conversion efficiency (PSC) as high as 19.77% and a fill factor over 83%. Equally importantly, the corresponding solar cells demonstrate a remarkable enhanced stability, maintaining 90% of its initial efficiency for more than 1200h without encapsulation under a 20% ± 5% relative humidity.