All-inorganic Perovskite Solar Cells Research Articles

Advanced Surface Passivation Enables High-Performance Carbon-Based All-Inorganic Perovskite Solar Cells

Advanced Surface Passivation Enables High-Performance Carbon-Based All-Inorganic Perovskite Solar Cells

Preparation of efficient all-inorganic perovskite solar cells from large grain via 1-heptanamine stabilised CsPbI2Br nanoparticles with NH4SCN additive

CsPbI2Br is a potential material for perovskite solar cells (PSCs) due to its better thermal stability and high efficiency. Centrifugal deposition for film formation greatly simplifies the steps of the conventional anti-solvent spin coating method, but there are still problems hindering progress, such as small grain size and poor photoelectric performance. In this work, NH4SCN was introduced as an additive during the preparation of heptylamine (C7H17N) stabilised CsPbI2Br nanoparticles (NCs) and the films were prepared by centrifugal deposition. The results show that the low melting temperature compounds which formed by thiourea from NH4SCN decomposition during annealing and unreacted PbX2 would link the small grains together by melting and flowing; after PbX2 precipitation and reaction with CsX, the grain size was significantly increased by about 95 % compared to that of the untreated film. Due to large grains, less defects and high crystallinity, the final power conversion efficiency and fill factor reached 12.25 % and 0.70, respectively.

Crystallization Control to Prepare Uniform CsPbI2Br Thin Films for High-Efficiency Perovskite Solar Cells.

All-inorganic perovskite solar cells (PSCs) face challenges related to film inhomogeneity, which arises from nonideal crystallization. This issue significantly impedes the advancement of all-inorganic PSCs. In this study, we observed that during the crystallization process of CsPbI2Br, the Br-rich intermediate phase is often preferentially deposited, leading to an uneven distribution in the out-of-plane direction of the perovskite film. To address this issue, crown ether molecules (dibenzo-18-crown-6) were introduced into the perovskite precursor solution. The complexation of crown ether with Cs cations and Br anions optimizes the crystallization sequence of the perovskite, ensuring that the intermediate phase closely conforms to the standard stoichiometric ratio. This adjustment significantly mitigates the problem of uneven halogen ion distribution along the out-of-plane direction. Furthermore, the crown ether thermally decomposes during the high-temperature annealing process, thereby not affecting the composition of the final perovskite film. Following crown ether treatment, the efficiency of the PSCs reached 14.08%, and the unpackaged devices maintained 80% of their initial efficiency after 1000 h of exposure to light in an atmospheric environment.

Sublimation and Recrystallization of CsPbBr3 Constructing a Perovskite-Carbon Interface to Facilitate Hole Transfer in Printable All-Inorganic Perovskite Solar Cells.

All-inorganic perovskite solar cells (APSCs) are a promising photovoltaic technology due to their unique physical and optical properties. For printable all-inorganic perovskite solar cells, the key factors limiting their photoelectric conversion performance are the crystallization of perovskite and the hole collection capability at the perovskite-carbon interface. In this study, leveraging the high-temperature tolerance of CsPbBr3 perovskite, the sublimation and recrystallization processes were controlled, significantly improving the crystalline quality of the perovskite and suppressing the generation of the nonphotovoltaic CsPb2Br5 phase. Furthermore, a continuous distribution of high-quality CsPbBr3 crystals was achieved at the interface between the carbon electrode and the zirconium oxide layer, ensuring efficient collection of photogenerated holes. The photoelectric conversion efficiency of the printable mesoscopic all-inorganic perovskite solar cell was increased from 5.04 to 8.34% (with a record value of 10.04%) and achieved an ultrahigh open-circuit voltage of 1.54 V due to the significant improvement in the crystal quality of CsPbBr3. This study proposes a novel strategy to enhance the photovoltaic conversion performance of carbon-based all-inorganic perovskite solar cells by suppressing the presence of nonphotovoltaic phases.

CaF2 Nanoparticle-Induced γ-CsPbI2.81Br0.19 Heterogeneous Crystallization for High-Efficiency Flexible All-Inorganic Perovskite Solar Cells.

All-inorganic CsPbI3 films necessitate higher annealing temperatures for high-quality crystallization. Consequently, the conventional low-temperature solution approach often results in poor crystallization in flexible CsPbI3 films, significantly degrading the optoelectronic performance and stability of flexible perovskite solar cells (f-PSCs). Herein, a heterogeneous CaF2 nanocrystal seed-induced strategy has been successfully utilized to achieve enhanced crystallization of a flexible CsPbI2.81Br0.19 film. Due to their good lattice match with the perovskite material, CaF2 nanoparticles can decrease the critical Gibbs free energy of CsPbI2.81Br0.19 perovskite nucleation, thereby accelerating γ-phase CsPbI2.81Br0.19 crystallization at low temperatures. This leads to an improved crystalline quality of the flexible perovskite film at low temperatures, which minimizes defects and enhances the stability of f-PSCs. The CsPbI2.81Br0.19 f-PSCs achieved a champion power conversion efficiency of 15.03% and demonstrated mechanical stability, retaining 98.1% of their initial efficiency even after 60 000 bending cycles with a curvature radius of 5 mm.

Regulation of the Buried Interface to Achieve Efficient HTL-Free All-Inorganic CsPbI2Br-Based Perovskite Solar Cells.

The large voltage loss (Vloss) mainly stems from the mismatch between the perovskite film and electron transport layer in CsPbI2Br-based all-inorganic perovskite solar cells (I-PSCs), which restricts the power conversion efficiency (PCE) of devices. To address this issue, potassium benzoate (BAP) is first introduced as a bifunctional passivation material to regulate the TiO2/CsPbI2Br interface, reduce the Vloss, and improve the photovoltaic performance of CsPbI2Br-based I-PSCs. Eventually, the champion PCE of CsPbI2Br-based I-PSCs without a hole transport layer modified by BAP (Target-PSCs) improves to 14.90% from the 12.14% of reference PSCs. The open-circuit voltage (Voc) increases to 1.27 V from the initial 1.14 V after BAP modification. A series of characterizations show that BAP modification can not only optimize the energy level alignment of I-PSCs but also passivize the surface defects caused by uncoordinated Cs+/Pb2+. Moreover, the Target-PSCs without encapsulation demonstrate better thermal stability, which can maintain 107.6% of the original PCE after annealing at 160 °C for 140 min in humid air. While the reference PSCs only maintain 76.5% of their initial PCE after annealing at the same process. This work provides a simple strategy to modify the buried interface and improve the performance of CsPbI2Br-based I-PSCs.

Synergetic effect of non-invasive posttreatment agents enables highly efficient and stable all-inorganic Sn-Pb perovskite solar cells

All-inorganic tin–lead perovskites present a promising avenue for achieving an ideal bandgap, approaching the Shockley-Queisser limit, while circumventing the use of volatile organic cations. However, challenges such as relatively low power conversion efficiency (PCE) and rapid degradation dynamics—stemming from complex film crystallization mechanisms and Sn oxidation—hinder their advancement. In this study, we employed sequential interface engineering on the CsPb0.6Sn0.4I3 system, utilizing non-invasive carbazole propylamine bromide and ethylenediamine diiodide as post-treatment agents. This approach significantly enhances both the bulk structure and surface morphology, thereby promoting charge transport, suppressing non-radiative recombination, and improving structural stability. The champion device achieved a PCE of 16.62 % and demonstrated over 2200 h of T80 stability in dry N2. Remarkably, stability in high-humidity environments was validated through device aging tests and in situ GIWAXS analysis. These results underscore the substantial potential of sub-1.4 eV bandgap all-inorganic Sn-Pb perovskite solar cells.

Exploring the impact of halide composition on stability and power conversion efficiency in all-inorganic perovskite solar cells

Exploring the impact of halide composition on stability and power conversion efficiency in all-inorganic perovskite solar cells

Efficient and stable all-inorganic perovskite solar cells prepared with ABX3-like precursors

Despite the fact that inorganic perovskites with supreme thermal stability are attractive photo-absorbers for emerging photovoltaic cells, intrinsic phase-instable issues pose challenges for obtaining satisfactory photovoltaic efficiencies and long-term device stability. Herein, we demonstrate an all-solution approach based on a series of perovskite-like products (PLP), namely NH4PbX3 (X = halogen) as the reactant for preparing inorganic perovskites featuring a heterojunction-resembling structure (HRS) and high material robustness. The creation of HRS is enabled by a self-migration and assembly process facilitated by the volatile characteristics of PLPs, as affirmed by joint experiential and theoretical investigations. We highlight that the particular structure of HRS is a key to the boost in material robustness, which translates to long-term device stability. Engaging compositional engineering on the PLPs allows us to regulate the energetics of surface components within the HRS, leading to gradient energy alignments to promote carrier transport and extraction in the device. Based on an optimized PLP (NH4PbCl2.8Br0.2) to form the HRS, the resultant solar cell yields a power conversion efficiency (PCE) exceeding 20 %, showing excellent operational stability under illumination (the efficiency remains over 95 % of its initial value after 1000 hours of continuous illumination). The described PLP-based approach can be readily applied to a range of inorganic perovskite materials for receiving gains in photovoltaic performance.

Self-Assembled Monolayer Suppresses Interfacial Reaction between NiOx and Perovskite for Efficient and Stable Inverted Inorganic Perovskite Solar Cells.

Inorganic NiOx has attracted tremendous attention in organic-inorganic hybrid perovskite solar cells (PSCs) in recent years but is relatively less used in all-inorganic PSCs. In this study, we have discovered and confirmed the detrimental interfacial reaction between NiOx and DMAI-containing CsPbI3 inorganic perovskites. Thus, a self-assembled monolayer, Br-2PACz, is employed to modify the NiOx surface to obstruct the adverse interfacial reaction and further improve the device performance. The results demonstrate that Br-2PACz modification on NiOx can also improve interface contact, perovskite film morphology, and energy level alignments. Consequently, a champion power conversion efficiency (PCE) of 19.34% with a high open-circuit voltage (VOC) of 1.15 V is obtained for inverted NiOx/Br-2PACz-based CsPbI3 PSCs compared to the reference NiOx-based PSC with a moderate PCE of 15.16% (VOC 1.05 V). Moreover, the stabilities of both CsPbI3 films and devices exhibited significant enhancement after Br-2PACz modification. The unpacked PSCs could maintain 80, 73, and 89% of the initial efficiency after aging in 30-35% RH for 960 h, heating at 60 °C for 48 h, and continuous illumination for 284 h, respectively, highly superior to the reference devices. Our work offers a facile and effective approach for developing high-performance inverted NiOx-based CsPbI3 PSCs.

Energy Level Tuning in CsPbBr3 Perovskite Solar Cells through In Situ-Polymerized PEDOT Hole Transport Layer.

The all-inorganic CsPbBr3 perovskite solar cells exhibit excellent stability against humidity and thermal conditions as well as relatively low production cost, rendering them a gradually emerging research hot spot in the field of photovoltaics. However, the absence of a hole transport layer (HTL) in its common structure and the substantial energy level difference of up to 0.6 eV between the highest occupied molecular orbital (HOMO) level of CsPbBr3 and the work function of the carbon electrode have emerged as the primary factor limiting the improvement of its power conversion efficiency (PCE). In this work, the monomer 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) is spin-coated onto the surface of the CsPbBr3 film directly and then subjected to annealing; DBEDOT undergoes in situ polymerization to form poly(3,4-ethylenedioxythiophene) (PEDOT), which aims to ameliorate the issue of excessive energy level difference between CsPbBr3 and the carbon electrode, and to facilitate the extraction and transport efficiency of holes between the CsPbBr3 perovskite and the carbon electrode. Compared to the pristine device, the PCE of the device based on in situ polymerization is enhanced and achieves a maximum efficiency of 9.81%. Furthermore, the unencapsulated devices based on in situ polymerization maintain 95.9% of their original efficiency after 40 days of stability testing.

Multifunctional molecular bridge enabled interface passivation and strain release for stable and efficient all-inorganic perovskite solar cells

The precise management of the buried interface in n-i-p perovskite solar cells (PSCs) to achieve efficient charge extraction and transport is crucial for improving the photovoltaic performance. Here, a 4-chloro-2,5-dimethoxyaniline (CDA) modifier with multifunctional groups is utilized as a molecular bridge at the TiO2/CsPbBr3 buried interface to enhance the qualities of TiO2 and CsPbBr3 films and the arrangement of interface energy level. The chlorine atom in CDA can heal the oxygen vacancies defects on the TiO2 film surface, thereby improving its electron mobility and conductivity. The –O– and -NH2 groups in CDA play a passivation effect on the ions defects of CsPbBr3 film, and especially the two –O– groups can anchor the lattice Pb atoms of CsPbBr3 perovskite, which effectively reduce the trap states of CsPbBr3 film and release the residual lattice strain. The modification of CDA also improves the wettability and energy level of TiO2 film to optimize CsPbBr3 crystal growth and charge transport, respectively. Consequently, the CsPbBr3 PSCs with CDA molecular bridge free of encapsulation achieve a highly increased power conversion efficiency of 10.85%, in contrast with 8.16% value of the control device. After 720 h of storage at 85 °C and in air environment with 85% relative humidity, the efficiency of the CDA-modified device retains 93.1% of the initial value, demonstrating excellent long-term humidity and thermal stability.

Efficiency optimization of All-Inorganic perovskite solar cell device using NiOx and ZnO as charge transport layers

In this study, we have developed and refined an all-inorganic perovskite solar cell with the structure FTO/ZnO/CsPbBr3/NiOx/Au. This was accomplished by incorporating the inorganic perovskite CsPbBr3 and the inorganic charge transport layers ZnO and NiOx. We employed solvent engineering techniques such as dropping solvents like isopropyl alcohol (IPA) and ethyl acetate (EA) during the spin-coating process, along with optimizing the thickness of the absorber layer and annealing conditions to enhance the power conversion efficiency (PCE). Our evaluation of the impact of the CsPbBr3 absorption layer thickness on PCE revealed that efficiency improved with layer thicknesses up to 280 nm. Moreover, we investigated the influence of post-deposition annealing durations on CsPbBr3, experimenting with times of 0.5hr, 1hr, 2hr, 3hr, and 5hr. The optimal conversion efficiency of 0.91 % was attained with an annealing temperature of 225 °C for 2hr, particularly when the absorption layer thickness was set at 280 nm. These results suggest that the device structure optimization for all-inorganic perovskite quantum dot solar cells can be successfully applied for efficiency optimization.

Synthesis of VS4 and VO on carbon nanofibers for back interface modification in HTL free CsPbBr3-based perovskite solar cells

Carbon-based hole transport layer (HTL)-free all-inorganic perovskite solar cells (C-PSCs) exhibit advantages of simplified preparation procedure, high stability, and low cost, showcasing significant application potential. Nonetheless, the development of C-PSCs requires overcoming challenges such as the misalignment of energy levels between carbon counter electrode and the CsPbBr₃ perovskite, abundant defects at the perovskite/carbon back interface, and the carbon counter electrode's low conductivity. Herein, VS₄ and VO-deposited carbon nanofibers (CNF), termed VS₄@CNF and VO@CNF respectively, have been synthesized to adjust the work function and improve the conductivity of the carbon counter electrode. CsPbBr₃-based C-PSCs employing VS₄@CNF and VO@CNF as counter electrodes yield power conversion efficiencies of 7.88 % and 8.80 %, indicating great PCE enhancements of 15.4 % and 28.8 % as compared with the device with unmodified CNF counter electrodes. This improvement is attributed to the optimized conductivity and adjusted work function of the counter electrodes, which can optimize the energy level alignment, thereby enhancing charge carrier extraction and transport while effectively inhibiting recombination. Furthermore, VS₄@CNF and VO@CNF demonstrate a notable passivation effect on defects at the back interface. This study offers a valuable path for the design of novel carbon counter electrodes and the modification of the back interface in carbon-based all-inorganic C-PSCs.

Exploring eco-friendly novel charge transport materials for enhanced performance of tin based perovskite solar cell

This pioneering simulation study explores the potential of perovskite materials, particularly the non-toxic methyl ammonium tin iodide (MASnI3), in solar cell technology. The investigation focuses on eco-friendly, solution-processed compounds—specifically, WO3 and In2S3 as Electron Transport Layers (ETL) and MoO3 and WSe2 as Hole Transport Layer (HTL)—to develop planar n-i-p MASnI3 perovskite solar cell (PSC) devices. WO3 is chosen for its solution processing and high electron mobility, while In2S3 offers n-type properties, superior carrier mobility, non-toxicity, and thermal durability. MoO3 and WSe2 are selected as HTLs for their efficient charge transport capabilities. Utilizing the solar cell capacitance simulator (SCAPS-1D) software, the study systematically evaluates alternative charge-selective materials, considering various parameters such as thickness (0.1 µm to 1.5 µm for absorber and 0.1 µm to 0.35 µm for CTLs), doping concentration (3.2E10 to 3.2E16 for absorber and E16 to E20 for CTLs), defect density, and energy band offset for MASnI3 PSCs. Four distinct n-i-p device structures are optimized, yielding impressive PCE improvements ranging from 14.63 % to 25.34 %, a significant 3 % enhancement compared to initial results. Notably, the WO3/MASnI3/WSe2 configuration exhibits limitations in electrical performance, while the other optimized structures demonstrate substantial efficiency gains. Further analysis investigates the impact of reflecting coatings (10 % to 90 %), varying contact work functions (5.2–5.8 eV), and temperature (300–400 K) on photovoltaic parameters. Critical factors including energy band offset, recombination current profile, and built-in potential, are meticulously examined, laying the groundwork for advanced PSC implementation. The study culminates in the In2S3/MASnI3/MoO3 device configuration, which achieves a peak efficiency of 25.34 %, showcasing superior thermal stability and an enhanced fill factor, thus propelling all-inorganic PSCs towards practical implementation.

Inorganic-Derived 0D Perovskite Induced Surface Lattice Arrangement for Efficient and Stable All-Inorganic Perovskite Solar Cells.

The inverted inorganic CsPbI3 perovskite solar cells (PSCs) are prospective candidates for next-generation photovoltaics owing to inherent robust thermal/photo-stability and compatibility for tandems. However, the performance and stability of the inverted CsPbI3 PSCs fall behind the n-i-p counterparts due to poor energetic alignment and abundant interfacial defect states. Here, an inorganic 0D Cs4PbBr6 with a good lattice strain arrangement is implemented as the surface anchoring capping layer on CsPbI3. The Cs4PbBr6 perovskite induces enhanced electron-selective junction and thus facilitates efficient charge extraction and effectively inhibits non-radiative recombination. Consequently, the CsPbI3 PSCs with Cs4PbBr6 demonstrate the highest power conversion efficiency (PCE) of CsPbI3-based inverted PSCs, reaching 21.03% PCE from a unit cell and 17.39% PCE from a module with a 64 cm2 aperture area. Furthermore, the resulting devices retain 92.48% after 1000h under simultaneous 1-sun and damp heat (85°C / 85% relative humidity) environment.

Enhancing efficiency and stability of perovskite solar cells with Bi2Te3 interlayer: insights from SCAPS simulation

Perovskite solar cells (PSCs) have gained much interest due to their high power conversion efficiencies (PCE). Affordable, accessible, and efficient solar energy is crucial for a sustainable and clean future. In this article, we optimized PSC efficiency and performance with an interlayer (IL) of Bi2Te3 (BT). Cell performance and efficiency were improved by incorporating BT IL with varied thicknesses. BT IL promotes electron transport while protecting the underlying structure from chemical instability, improving device performance. This simple and low-cost technology for producing efficient and stable all-inorganic PSC holds considerable potential as a next-generation renewable energy source. The main focus is optimizing all-inorganic PSC using Solar Cell Simulator Capacitance software (SCAPS). We systematically explore the influence of BT thickness and defect densities on the device performance. The impact of charge carrier transport and overall photovoltaic performance is studied. Our findings reveal that introducing the BT IL leads to improved charge extraction, reduced recombination losses, and enhanced stability in the PSC. The optimized device configuration significantly enhances PCE compared to reference devices without BT IL. This study provides valuable insights into the potential use of BT ILs as a strategy to boost the efficiency and stability of PSCs.

In Situ PL Probes the Effect of 2D SnSe Nanosheets on the Crystallization Process of CsPbI2Br Perovskite Solar Cells.

Reducing defects in the active layer is important for improving the crystalline quality of all-inorganic perovskite solar cells (PSCs). Exploring novel additives is one of the most promising approaches to minimize active layer defects. In this work, two-dimensional (2D) SnSe nanosheets with excellent optoelectronic properties are prepared using an ultrasonic exfoliation method. The prepared 2D SnSe nanosheets are introduced into a CsPbI2Br precursor, which reduces the defect formation at grain boundaries and enhances the crystallinity of CsPbI2Br perovskites. We use the in situ photoluminescence (PL) technique to investigate the role of 2D materials in the crystallization process. The results show that SnSe nanosheets primarily shorten the grain boundary merging time and reduce the defect generation during the grain boundary merging stage, thereby regulating the crystallization of perovskite. In addition, SnSe nanosheets passivate uncoordinated Pb atoms at grain boundaries by Se atoms, further reducing the defect density in perovskite. As a result, PSCs exhibit a higher power conversion efficiency (PCE) of 14.24% and a Voc of 1.22 V. This study highlights the role of 2D materials in enhancing the crystalline quality and PCE of PSCs.

Enhancing efficiency and performance of Cs2TiI6-based perovskite solar cells through extensive optimization: A numerical approach

The commercial production of lead-based perovskite solar cells (PSCs) is hindered due to toxicity difficulty and all Ti-based all-inorganic PSCs may give a practical solution to these problems. This work optimizes the different layers of a PSC based on the Cs2TiI6 absorber layer. In order to produce four unique structures, ten distinct HTLs are considered to identify the best HTL, and after that four ETLs are utilized. These structures are then optimized using SCAPS 1D simulation software. The thickness of the absorber and electron transport layer (ETL), as well as the acceptor and defect density of the absorber, and the acceptor density of the hole transport layer (HTL), were optimized sequentially. After the optimization, the best PCE of 28.03 % along with VOC, JSC, and FF of 1.11 V, 28.39 mA/cm2, and 89.01 % were found, correspondingly for the structure of FTO/SnS2/Cs2TiI6/MoTe2/Au. Additionally, the effects of temperature, series resistance, and shunt resistance were investigated with regard to the four most promising devices. The generation and recombination rates, together with the reported properties of current-voltage density (J-V) and quantum efficiency (QE), are also relevant to the first and last optimized devices in the four-device investigation.

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.