Planar Heterojunction Solar Cells Research Articles

Parallel Planar Heterojunction Strategy Enables Sb2S3 Solar Cells with Efficiency Exceeding 8 %

AbstractSolution‐processed solar cells based on inorganic heterojunctions provide a potential approach to the efficient, stable and low‐cost solar cells required for the terrestrial generation of photovoltaic energy. Antimony trisulfide (Sb2S3) is a promising photovoltaic absorber. Here, an easily solution‐processed parallel planar heterojunction (PPHJ) strategy and related principle are developed to prepare efficient multiple planar heterojunction (PHJ) solar cells, and the PPHJ strategy boosts the efficiency of solution‐processed Sb2S3 solar cells up to 8.32 % that is the highest amongst Sb2S3 devices. The Sb2S3‐based PPHJ device consists of two kinds of conventional planar heterojunction (PHJ) subcells in a parallel connection: Sb2S3‐based PHJ subcells dominating the absorption and charge generation and CH3NH3PbI3‐based PHJ subcells governing the electron transport towards collection electrode, but it belongs to an Sb2S3 device in nature. The resulting PPHJ device combines together the distinctive structural features of Sb2S3 absorbing layer as a main absorber and the duplexity of well‐crystallized/oriented CH3NH3PbI3 layer in charge transportation as an additional absorber, while the presence of perovskite does not affect device stability. The PPHJ strategy maintains the facile preparation by the conventional sequential depositions of multiple layers, but eliminates the normal complexity in both tandem and parallel tandem PHJ systems.

Parallel Planar Heterojunction Strategy Enables Sb2 S3 Solar Cells with Efficiency Exceeding 8 .

Solution-processed solar cells based on inorganic heterojunctions provide a potential approach to the efficient, stable and low-cost solar cells required for the terrestrial generation of photovoltaic energy. Antimony trisulfide (Sb2 S3 ) is a promising photovoltaic absorber. Here, an easily solution-processed parallel planar heterojunction (PPHJ) strategy and related principle are developed to prepare efficient multiple planar heterojunction (PHJ) solar cells, and the PPHJ strategy boosts the efficiency of solution-processed Sb2 S3 solar cells up to 8.32 % that is the highest amongst Sb2 S3 devices. The Sb2 S3 -based PPHJ device consists of two kinds of conventional planar heterojunction (PHJ) subcells in a parallel connection: Sb2 S3 -based PHJ subcells dominating the absorption and charge generation and CH3 NH3 PbI3 -based PHJ subcells governing the electron transport towards collection electrode, but it belongs to an Sb2 S3 device in nature. The resulting PPHJ device combines together the distinctive structural features of Sb2 S3 absorbing layer as a main absorber and the duplexity of well-crystallized/oriented CH3 NH3 PbI3 layer in charge transportation as an additional absorber, while the presence of perovskite does not affect device stability. The PPHJ strategy maintains the facile preparation by the conventional sequential depositions of multiple layers, but eliminates the normal complexity in both tandem and parallel tandem PHJ systems.

Modeling and Investigation of Highly Efficient Environment Friendly Perovskite Solar Cell with CuSbS2 as Hole Transport Layer

The presence of lead and its associated toxicity represents a hindrance to the broad commercial production of lead halide perovskites and their utilization in solar photovoltaic devices. Although lead halide perovskites have found extensive application in solar cell technology, questions have arisen regarding the hazardous nature and durability of lead (Pb) in photovoltaic systems. This research seeks to address these concerns by exploring alternative materials, such as tin-based perovskites, to pave the way for cleaner and more sustainable energy solutions. The scientific community has shown increased interest in tin-based perovskites due to their superior efficiency and stability compared to lead-based perovskite solar cell. This research introduces a planar heterojunction solar cell utilizing tin-based perovskites that are free of lead. The simulation task was conducted using SCAPS-1d software. Device parameters for a lead-free PSC (perovskite solar cell) using significant framework FTO/WS2/CH3NH3SnI3(perovskite)/CuSbS2 included an examination of factors like perovskite layer thickness, the obsession of acceptors in the perovskite layer, defects density of perovskite layer, and the band gap of the perovskite layer. In this setup, WS2 served as the ETL material, CuSbS2 functioned as the HTL material, and the CH3NH3SnI3(Perovskite) was used as the absorber layer material. This configuration achieved an impressive PCE 32.5%, along with a Jsc34.1mAcm-², Voc1.02V and FF85.5%. These optimized results likelihood indicates the strong prospect for development of an eco-friendly and efficient model of PSC (perovskite solar cell).

Highly efficient SnS-based inverted planar heterojunction solar cell with ZnO ETL

Tin Sulfide (SnS) is a promising absorber material for solar energy harvesting owing to the high absorption coefficient. Here, a novel inverted planar heterostructure of SnS based solar cell (ITO/NiOX/SnS/ZnO/Al) has been proposed for better efficiency among the different electron transport layers (ETLs), PCBM, C60, CeOX, and ZnO. The performance of the SnS based solar cell was theoretically studied by the Solar Cell Capacitance Simulator (SCAPS) software. Initially, we have been observed the device performance with different ETL materials to find the better ETL material. The layer parameters of the HTL, absorber layer, and ETLs have been optimized to find out the best performance of the device. The device showed efficiencies of around 26.44%, 26.33%, and 26.38% with the ETLs PCBM, C60, and CeOX respectively. The maximum power conversion efficiency (PCE) of ∼28.15% has been observed after incorporating ZnO ETL in the designed architecture of the SnS-based solar cell. Then, we have been investigated the performance of the SnS-based solar cell with ZnO ETL for the various value of carrier concentration, thickness, and bulk defect of the SnS absorber layer, defect of the interfaces of NiOX/SnS and SnS/ZnO, back metal contact’s work function, and its operating temperature. The variation of the different parameters has exhibited a substantial effect on the device performance. The VOC, JSC, FF, and PCE of the optimized SnS-based solar cell with ZnO ETL showed 0.8954 V, 37.316452 mA cm−2, 84.24%, and 28.15%, respectively. The visualization of the results indicates that ZnO might be a potential ETL for the highly efficient, low-cost inverted planar solar cells based on SnS.

Charge Carrier Dynamics in Planar Heterojunction Organic Solar Cells

The ionization energy (IE) offset of a donor–acceptor pair provides the driving force for hole transfer and subsequent free charge carrier generation in low‐bandgap nonfullerene organic solar cells (OSCs). However, the interfacial energetic landscape in bulk heterojunction OSCs is determined by the materials’ electronic structure and intermolecular interactions at the donor/acceptor interface, causing local energy‐level shifts and disorder. Herein, the impact of the IE offset on the charge transfer efficiency and charge carrier dynamics is systematically evaluated by characterizing PM6/ITIC, PM6/IT‐2Cl, and PM6/IT‐4Cl planar heterojunction (PHJ) solar cells. Ultrafast spectroscopy and time‐resolved charge carrier density measurements reveal that an IE offset of about ≈0.5 eV leads to efficient hole transfer and subsequent free charge generation. Furthermore, bimolecular charge recombination and consequently triplet generation are significantly reduced in systems with high IE offset. This work underlines the importance of sizeable donor–acceptor IE offsets in PHJ nonfullerene OSCs as critical for high‐efficiency donor/acceptor material and device design.

Improving open-circuit voltage and short-circuit current of high-efficiency silicon-based planar heterojunction solar cells by combining V2O5 with PEDOT:PSS

In recent years, a novel PEDOT:PSS/n-Si planar heterojunction solar cell has been extensively studied in the photovoltaic field. Different V2O5-IPA concentrations mixed in PEDOT:PSS samples as hole transport layer were prepared by means of spin coating technique and mechanical mixing of organic and inorganic materials. V2O5 was studied for its effects on the surface morphology, chemical composition, and optical transmittance of PEDOT:PSS films. The findings of the study show that the addition of V2O5 particles changes the surface morphology of PEDOT:PSS films and promotes its superior ohmic contact with the Si interface. Furthermore, PEDOT:PSS incorporated with V2O5 particles that have outstanding optical and semiconductor properties reduces the rate of carrier recombination at the device interface and blocks electron transport to the anode in the fabricated Si-based solar cells. When compared to conventional PEDOT:PSS/Si planar heterojunction solar cells, the fill factor, photoelectric conversion efficiency, open-circuit voltage, and short-circuit current density of the devices prepared in this study can be significantly improved, reaching up to 70.98%, 15.17%, 652 mV and 32.8 mA/cm2, respectively. This research provides a promising and effective method for improving the photoelectric conversion performance of PEDOT:PSS/Si heterojunction solar cells, which enables the application of V2O5 in Si solar cells.

Quantifying the effect of energetic disorder on organic solar cell energy loss

•Correlation between non-radiative energy loss and CT-state energetic disorder •D-A interface optimization strategy for reduced non-radiative energy loss •Universal energy loss metric incorporating disorder Understanding the factors affecting energy loss in organic photovoltaics (OPVs) is imperative to achieve further improvements in their efficiency and to establish design rules for the development of new materials. Here, we provide direct experimental evidence supporting correlation between charge-transfer (CT) state static disorder and energy loss. Specifically, upon studying several planar and bulk heterojunction solar cells, we demonstrate that the non-radiative energy loss component quadratically increases with increasing Gaussian CT-state disorder. We also show that by defining the total energy loss in terms of the peak of the CT-state distribution, obtained from temperature-dependent external quantum efficiency measurements, the effect of disorder on OPV performance can be unambiguously identified, offering a universal metric for quantifying energy loss across various devices. Understanding the factors affecting energy loss in organic photovoltaics (OPVs) is imperative to achieve further improvements in their efficiency and to establish design rules for the development of new materials. Here, we provide direct experimental evidence supporting correlation between charge-transfer (CT) state static disorder and energy loss. Specifically, upon studying several planar and bulk heterojunction solar cells, we demonstrate that the non-radiative energy loss component quadratically increases with increasing Gaussian CT-state disorder. We also show that by defining the total energy loss in terms of the peak of the CT-state distribution, obtained from temperature-dependent external quantum efficiency measurements, the effect of disorder on OPV performance can be unambiguously identified, offering a universal metric for quantifying energy loss across various devices.

Influence of layer thickness on the power conversion efficiency of tin halide-based planar heterojunction solar cells.

In recent years, perovskite-based solar cell technologies have sparked much interest. Organic-inorganic halide perovskites (OIHPs) are a type of perovskite that has shown promise in various optoelectronic applications. The power conversion efficiency (PCE) of organic-inorganic perovskite materials is improving with new materials development. However, inorganic materials studied in labs have limited PCE. Lead-free tin halide CH3NH3SnX3 shows good PCE. In this work, we study the electrical characteristics of tin halide as a perovskite absorbing layer in planar heterojunction solar cells with the help of GPVDM solar cell simulation software. A comparative study of power conversion efficiency has been done for tin halide of chloride, bromide, and iodide. The effect of electron and hole drift-diffusion, carrier continuity equations in position space to represent charge flow within the device, Poisson's equation, and charge carrier recombination has been studied in detail.

Interfacial Engineering towards Enhanced Photovoltaic Performance of Sb2Se3 Solar Cell

AbstractAntimony selenide (Sb2Se3) is a kind of emerging candidate for the application in low‐cost and high‐efficiency thin film solar cells owing to its non‐toxicity, earth‐abundance, and unique quasi‐1D crystal structure. In this photovoltaic material, quasi‐vertically oriented Sb2Se3 thin films can transfer photocarriers efficiently along the [hk1]‐orientation. However, the crystal orientation control in thin films is still the main obstacle to improve the efficiency of Sb2Se3 solar cells. Herein, an interfacial engineering method is developed by antimony chloride (SbCl3) on CdS films with post‐annealing treatment to improve the quality of both interface and absorber thin film. It is found that the SbCl3 treatment resulted in 1) transformation of the CdS/Sb2Se3 interface from “cliff” to “spike” like energy band alignments; 2) improved surface morphology of CdS surface, and 3) suppressed cubic structure of CdS structure and thus generating improved [hk1]‐oriented Sb2Se3 film on the high‐purity hexagonal CdS. As a result, the Sb2Se3 solar cell treated with SbCl3 achieves a top efficiency of 6.89% in superstrate planar heterojunction Sb2Se3 solar cell. This study provides a new interfacial post‐treatment method for the preparation of high‐performance Sb2Se3 planar heterojunction solar cells.

Device Modelling and Optimization of Nanomaterial-Based Planar Heterojunction Solar Cell (by Varying the Device Dimensions and Material Parameters).

The objective of this work is to model a multi-disciplinary (multi-physics) organic photovoltaic (OPV) using mathematical modeling and analyzing the behavior of a standard planar heterojunction (PHJ) or bi-layer thin-film photovoltaic device, supporting the optimization of an efficient device for future production and assisting in evaluating and choosing the materials required for the efficient device. In order to increase photodiode performance, the device structure and geometrical properties have also been optimized and evaluated. In this work, the effects of varying the device size and transport parameters on the performance parameters of a PHJ OPV structure comprised of Indium Tin Oxide as the anode (ITO), semiconducting single-wall carbon nanotube (s-SWCNT) as the donor, fullerene C70 as the acceptor, and Aluminium (Al) as the cathode have been analyzed. The conclusion suggests that a highly effective ITO/s-SWCNT/C70/Al PHJ solar cell may be fabricated if the suggested device is appropriately built with a thin layer and a high exciton diffusion length, bi-molecular recombination coefficient, and improved mobility charge carriers, in particular hole mobility in the cell’s donor layer. In addition, the displayed current–voltage (I–V) characteristics of the proposed PHJ device are clearly indicated, with the ITO/s-SWCNT/C70/Al combination having the greatest short-circuit current density (Jsc) value of 5.61 mA/cm2, open-circuit voltage (Voc) of 0.7 V, fill factor (FF) of 79% and efficiency (ɳ) of 3.1%. Results show that the electrical performance of organic solar cells is sensitive to the thickness of the photoactive substance. These results open the path for developing inexpensive and highly efficient solar cells.

A qualitative study of SnSe thin film solar cells using SCAPS 1D and comparison with experimental results: A pathway towards 22.69% efficiency

We simulated a tin selenide (SnSe) based solar cell device in a standard planar substrate configuration (glass/Mo/SnSe/CdS/i-ZnO/AZO/Al) using a Solar Cell Capacitance Simulator (SCAPS-1D) software to elucidate a path to higher power conversion efficiency (PCE). A baseline model for the device was simulated and established using the experimental results of our recent study on a 2.51% device. A stepwise fitting procedure observed a higher effective density of states in SnSe, along with a band offset of −0.11 eV for conduction between SnSe and CdS; these factors are responsible for limiting the open-circuit voltage ( V OC ). We optimized the buffer and absorber layer parameters to improve the working capabilities to achieve higher efficiency by improving V OC . In particular, the effects of carrier concentration, absorber–buffer interface recombination, absorber thickness, buffer layer thickness, and defect densities were studied and analyzed in detail via simulation. Interestingly, optimal absorber and buffer layer thicknesses of 1.2 μm and 60 nm were obtained for the baseline and simulated devices. Finally, a NiO back-surface field (BSF) layer was introduced, and its performance was evaluated. Significant improvements in V OC and fill factor (FF) were observed with implementing the NiO BSF layer at the SnSe/CdS interface. The optimal device without a BSF layer exhibited a maximum efficiency of 13.79% with a V OC of 0.590 V; a short-circuit current density ( J SC ) of 36.28 mA cm −2 , and an FF of 64.33%. Finally, the highest PCE of 22.69% with a V OC of 0.818 V, J SC of 33.65 mA cm −2 , and FF of 82.41% was observed after applying the BSF layer. • Simulation of SnSe/CdS-based solar cells using experimental results. • Role of NiO BSF in SnSe/CdS planar heterojunction solar cells. • Importance of VB and CB eDOS to enhance the solar cell performance. • Improvement in the fill factor and open-circuit voltage by introducing a NiO BSF layer.

Performance analysis of WSe2-based bifacial solar cells with different electron transport and hole transport materials by SCAPS-1D

In recent years, solar cells made of tungsten diselenide (WSe2) have received comprehensive consideration because of their good photoelectric properties. The planar WSe2-based heterojunction solar cell with a preliminary device structure of Au/WSe2/electron transport layer (ETL)/FTO/Al was designed and investigated numerically by SCAPS-1D. CdS ETL is widely used in thin film solar cells (TFSCs). Due to environmental issues and the low band gap (2.42 eV) of CdS ETL, an alternative to CdS ETL was being explored for WSe2 solar cells. In this work, the photovoltaic (PV) performance of the WSe2-based TFSCs with different ETLs were simulated, analyzed and compared, in an attempt to track down a suitable substitute for the CdS ETL. In addition to CdS ETL, ZnO, TiO2 and SnO2 ETLs were independently used to simulate the PV performance of WSe2-based TCSCs. In the wake of analyzing the J-V curves of different cell configurations, SnO2 ETL yielded the best results with PCE of 27.14 % for the single-junction WSe2/SnO2 TFSC. Then, our simulation predicted that the PV performance of the WSe2 device can be improved significantly by using N doped Cu2O as a hole transport layer (HTL). The optimized WSe2 device with SnO2 ETL and Cu2O:N HTL showed an improved PCE of 33.84 % with very good performance stability at higher temperature. Furthermore, this article proposes to use the Au/Cu2O:N/WSe2/SnO2/FTO/Al heterojunction solar cell in bifacial mode and PV performance of the proposed bifacial device have been also studied using SCAPS-1D. Bifacial WSe2 device leads to enhanced PV performance with bifaciality factor for PCE is 83.64 %. Bifacial gain of the proposed device under simultaneous irradiation of 1 sun from the front and 20 % of 1 sun from back side is found to be 13.95 %. Our simulation predicts that the proposed WSe2 bifacial solar cell is capable of converting solar energy into electricity with an efficiency of about 38.38 %.

Utilization of Multifunctional Environment‐Friendly Organic Dopants Inspired from Nature for Carbon Nanotube‐Based Planar Heterojunction Silicon Solar Cells

Herein, eco‐friendly natural acids inspired by nature, namely, acetic acid, formic acid, lactic acid, and citric acid on their capability of functioning as a p‐dopant for the carbon nanotube transparent electrode in silicon‐based planar heterojunction solar cells, are tested. From the result, lactic acid shows the multifunctional effect of p‐doping with excellent doping stability as well as antireflection. The doping effect and its stability are investigated by diverse methods, such as van der Pauw four‐probe measurement as well as Raman, photoelectron yield, and absorption spectroscopy. The sheet resistance decreases by 22.1% when carbon nanotube films are doped by lactic acid and the doped films are stable for more than 20 days. The antireflection effect of lactic acid coating is confirmed by atomic force microscopy, ellipsometry, computational analyses, and reflectance spectroscopy. The power conversion efficiency of carbon nanotube‐laminated silicon solar cells improves from 8.2% to 10.3% by using nature‐inspired lactic acid. Such a great improvement is ascribed to not only the p‐doping and antireflection effects but also the passivation effect of lactic acid on the Si surface defect sites as evidenced by both the Fourier‐transform infrared and the Quasi‐steady‐state photoconductance lifetime measurements.

Antisolvents Treatment of Cs0.15FA0.85PbI3 Boosting Efficiency for Perovskite Solar Cells

One-step spin-coating solution deposition was reported as an excellent processing method in perovskite solar cells (PSCs). Antisolvent treatment has been demonstrated to significantly enhance the power conversion efficiency (PCE) of PSCs owing to the formation of high-quality perovskite crystals and passivation of defects. In this article, we alter different antisolvents in solution deposition process, i.e., chlorobenzene, toluene, and diethyl ether, combined with different measurements of scanning electron microscopy, atomic force microscopy, X-ray diffraction, time-resolved photoluminescence, and UV–vis absorption spectrum (UV–vis) to investigate the evolution of perovskite thin films. These results illustrate that a smooth and compact perovskite layer by antisolvent treatment is beneficial to enhancing device performance. A high coverage, large crystal size and smooth Cs <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.15</sub> FA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</sub> PbI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> thin film with a long carrier lifetime attained via antisolvent treatment is utilized to fabricate an inverted planar heterojunction solar cell, which exhibits PCE more than 15%.

Templated Growth and Passivation of Vertically Oriented Antimony Selenide Thin Films for High‐Efficiency Solar Cells in Substrate Configuration

AbstractAntimony selenide (Sb2Se3) is a promising low‐cost photovoltaic material with a 1D crystal structure. The grain orientation and defect passivation play a critical role in determining the performance of polycrystalline Sb2Se3 thin‐film solar cells. Here, a seed layer is introduced on a molybdenum (Mo) substrate to template the growth of a vertically oriented, columnar Sb2Se3 absorber layer by closed space sublimation. By controlling the grain orientation and compactness of the Sb2Se3 seeds, obtain high‐quality Sb2Se3 absorber layers with passive Sb2Se3/Mo interfaces is obtained, which in turn improve the transport of photoexcited charge carriers through the absorber layer and its interfaces. Post‐deposition annealing of absorber layers in ambient air is further utilized to passivate the defects in Sb2Se3 and enhance the quality of the front heterojunction. As a result of systematic processing optimization, Sb2Se3 planar heterojunction solar cells are fabricated in substrate configuration with a champion power conversion efficiency of 8.5%.

Fabrication and Characterization of Polypyrrole/Multi-Walled Carbon Nanotubes Thin Films Using Thermal Evaporation.

Polypyrrole/multiwalled carbon nanotubes composites (PPy/MWCNTs) were produced in an acidic solution utilizing an in situ oxidative polymerization method using ferric chloride as an oxidizing agent and sodium dodecyl sulfate as a soft template. Thermal evaporation was used to fabricate thin films from polypyrrole/multiwalled carbon nanotube composites. The resulting composites were examined by different techniques to explore their morphology, structural and electrical characteristics. The surface morphology analysis revealed that polypyrrole structure is a two-dimensional film with impeded nanoparticles and the thickness of coated PPy around the MWCNTs decreases when increasing the amount of MWCNTs. XRD analysis revealed that the average crystallite size of the prepared composites is 62.26 nm. The direct energy gap for PPy is affected by a factor ranging from 2.41 eV to 1.47 eV depending on the contents of MWCNTs. The thin film’s optical properties were examined using experimental and TDDFT-DFT/DMOl3 simulation techniques. The optical constants and optical conductivity of the composites were calculated and correlated. The structural and optical characteristics of the simulated nanocomposites as single isolated molecules accord well with the experimental results. The nanocomposite thin films demonstrated promising results, making them a viable candidate for polymer solar cell demands. Under optimal circumstances, the constructed planar heterojunction solar cells with a 75 ± 3 nm layer of PPy/MWCNTs had a power conversion efficiency (PCE) of 6.86%.

In-situ hydrothermal growth of MoS2 absorber layer for planar heterojunction solar cells

MoS2 thin film is deposited on ITO/CdS substrate by in-situ hydrothermal method,which is expected to be a potential absorber material for planar heterojunction solar cell due to its high absorber coefficient and carrier mobility. The CdS buffer layer provides a robust template for the quasi-epitaxial growth of MoS2 with (002) preferred orientation by enjoying the analogical hexagonal structures and the shared sulfur atoms, resulting in a benign interface of CdS/MoS2. Then a device with ITO/TiO2/CdS/MoS2/Carbon-Ag structure is assembled after coating carbon-Ag electrode. The effects of the growth characteristics, morphology changes and optical properties of MoS2 on the device performance are studied systematically.Finally, a primary efficiency of 0.12% is achieved using a P-type MoS2 absorber with a thickness of 305 nm, exhibiting an outstanding stability. The one-dimensional solar cell capacitance simulator (SCAPS) is further used to reveal the bottleneck of device performance. After optimizing the doping density (1 × 1015 cm−3) and defect density (<5 × 1015 cm−3) of MoS2 film as well as inserting a hole transport layer, the efficiency of MoS2 planar device can be enhanced to 10.77%. This work provides an in-situ growth route for constructing a CdS/MoS2 planar heterojunction as a potential candidate for the low-cost solar cells.

Towards high-efficiency planar heterojunction antimony sulfide solar cells

Recently, antimony sulfide (Sb2S3) based solar cells have received substantial attention, however their practical efficiency is far from ideal. Therefore, it is critical to provide numerical simulation on the devices, giving possible avenues to improve the performance. A planar heterojunction solar cell with a structure of FTO/electron transport layer (ETL)/Sb2S3/Cu2O/Au was investigated theoretically by Solar Cell Capacitance Simulator (SCAPS). The influence of different ETLs (CdS, TiO2, ZnO) and Cu2O layer has been firstly analyzed, and our results show that the best ETL is TiO2, and the device efficiency can be significantly increased when Cu2O is used as a hole transport layer (HTL). Then, the electron affinity of TiO2, Sb2S3 layer thickness, defect density, and metal work function on device performance have also been studied systematically. The best electron affinity of TiO2 is 3.6 eV, because a small positive conduction band offset (ΔEC = 0.1 eV) at the TiO2/Sb2S3 interface can be formed, enhancing carrier transport, and consequently, improving the device performance. Further, the optimal thickness for Sb2S3 layer is 200 nm when the defect density of the Sb2S3 layer is 1015 cm−3. To achieve ideal performance, the defect densities in the Sb2S3 layer and at the Sb2S3 interfaces should be as low as 1012 cm−3 and 2 × 1015 cm−2, respectively. In addition, the work function of the metal electrode larger than 4.9 eV is beneficial to device performance. Finally, a Sb2S3 solar cell with the conversion efficiency of 21.43% can be achieved after optimization, which performance is close to the conventional thin film solar cells. Our simulation results suggest the potential of Sb2S3 solar cells.

Organic-Inorganic Perovskite Films and Efficient Planar Heterojunction Solar Cells by Magnetron Sputtering.

Organic–inorganic halide perovskites have been widely used in photovoltaic technologies. Despite tremendous progress in their efficiency and stability, perovskite solar cells (PSCs) are still facing the challenges of upscaling and stability for practical applications. As a mature film preparation technology, magnetron sputtering has been widely used to prepare metals, metallic oxides, and some semiconductor films, which has great application potential in the fabrication of PSCs. Here, a unique technology where high‐quality perovskite films are prepared via magnetron sputtering for controllable composition, solvent‐free, large‐area, and massive production, is presented. This strategy transforms the perovskite materials from powder to thin films by magnetron sputtering and post‐treatment (vapor‐assisted treatment with methanaminium iodide gas and methylamine gas treatment), which is greatly favorable to manufacture tandem solar cells. The power conversion efficiency (PCE) of PSCs with perovskite films fabricated by magnetron sputtering is 6.14%. After optimization, high‐performance perovskite films with excellent electronic properties are obtained and stable PSCs with excellent reproducibility are realized, showing a PCE of up to 15.22%. The entirely novel synthetic approach opens up a new and promising way to achieve high‐throughput magnetron sputtering for large‐area production in commercial applications of planar heterojunction and tandem PSCs.

Improvement of interfacial contact for efficient PCBM/MAPbI3 planar heterojunction solar cells with a binary antisolvent mixture treatment

Atomic-force microscopic images, x-ray diffraction patterns, Urbach energies and photoluminescence quenching experiments show that the interfacial contact quality between the hydrophobic [6,6]-phenyl-C61-buttric acid methyl ester (PCBM) thin film and hydrophilic CH3NH3PbI3 (MAPbI3) thin film can be effectively improved by using a binary antisolvent mixture (toluene:dichloromethane or chlorobenzene:dichloromethane) in the anti-solvent mixture-mediated nucleation process, which increases the averaged power conversion efficiency of the resultant PEDOT:PSS (P3CT-Na) thin film based MAPbI3 solar cells from 13.18% (18.52%) to 13.80% (19.55%). Beside, the use of 10% dichloromethane (DCM) in the binary antisolvent mixture results in a nano-textured MAPbI3 thin film with multicrystalline micrometer-sized grains and thereby increasing the short-circuit current density and fill factor (FF) of the resultant solar cells. It is noted that a remarkable FF of 80.33% is achieved, which can be used to explain the stable photovoltaic performance without additional encapsulations.