Solar Cell Absorber Research Articles

New Double Perovskite Solar Cell Containing Ba3PCl3 (A3BX3) and CsSnI3 (ABX3) Leading to an Improved Efficiency Above 30%

AbstractIn photovoltaic (PV) technology, halide perovskites stand out for their exceptional optical properties, improved performance, and cost‐effectiveness. This study utilized SCAPS‐1D to examine a novel dual absorber solar cell, using Ba3PCl3 as the top absorber and CsSnI3 as the bottom absorber, marking the first comprehensive analysis of this pairing. The research thoroughly investigated the thickness, doping concentrations, and defect densities of each absorber to evaluate their impact on electrical properties such as VOC, JSC, FF, and power conversion efficiency (PCE). Additionally, the study meticulously analyzed the effects of temperature, shunt, and series resistances. The results show that the first device (FTO/SnS2/Ba3PCl3/Au) achieved a PCE of 17.75%, while the second device (FTO/SnS2/CsSnI3/Au) reached a PCE of 20.63%. Optimized designs combining both absorbers (FTO/SnS2/Ba3PCl3/CsSnI3/Au) resulted in a PCE of 30.97%, with a JSC of 47.52 mA/cm2, FF of 80.42%, and VOC of 0.81 V. These promising findings offer valuable insights for the future development of experimental solar devices.

Solution-Crystalized AgBiS2 Films for Solar Cells Generating a Photo-Current Density Over 31mA cm-2.

In response to the toxic heavy metal absorbers in perovskite solar cells (PSCs), this work focuses on the development of an environmentally friendly simple solution-processed infrared (IR) absorber. In this work, a simple solution-crystallized IR-absorbing AgBiS2 film is reported by spin-coating silver, bismuth nitrates, and thiourea dissolved in dimethylformamide (DMF) to produce thick AgBiS2 film. Extensive optimization of the precursor concentrations thicknesses and conductive substrates used allow for obtaining 250nm AgBiS2 film with different crystal sizes. When applied as an absorber in solar cells, solution-crystalized AgBiS2 thick film delivers an extraordinarily high current density of over 31mA cm-2. The devices show high stability under continuous 100mW cm-2 illumination and when stored in the dark for more than six months. When the AgBiS2 layer is fabricated in a gradient fashion combining one layer of 0.25m and three layers of 0.5m precursor concentrations, the efficiency of 5.15% is registered which is the highest reported for the simple solution-crystallized AgBiS2 films.

The influence of precursor solutions containing an amount of silver bismuth sulfide nanoparticles (AgBiS2 NPs) on the characteristics of CH3NH3PbI3 perovskites solar cells

The utilization of organo-metal halide perovskites as absorbers in thin-film solar cells has garnered considerable interest from the scientific community in recent times. In this study, we present the introduction of silver bismuth sulfide nanoparticles (AgBiS2 NPs) doped into perovskite thin films composed of CH3NH3PbI3 thin film. Our results demonstrate that the perovskites' morphology and structure were significantly improved. The effects of AgBiS2 NPs concentration on the optical, mechanical, and crystallographic properties of CH3NH3PbI3 perovskite thin films were investigated. The findings from the structure investigations revealed that an increase in the concentration of AgBiS2 NPs resulted in a transition from a low-crystalline to a polycrystalline structure of the perovskite thin films. An elevation in the concentration of AgBiS2 NPs from 2 to 8 mg/mL led to the development of perovskite films of superior quality, consisting entirely of PbI3 and CH3NH3. These films exhibited almost impeccable deposition, compactness, and uniformity, and their particle size reached an approximate value of 1.3 μm. Furthermore, an increase in the optical absorption coefficient (∼105 cm−1) in the visible spectrum and subsequent enhancements in photoluminescence (PL) and ultraviolet–visible (UV–Vis) absorption spectroscopy serve as further evidence of the film's enhanced quality. When AgBiS2 NPs are doped into perovskites, the films' quality is significantly improved; they acquire a uniform surface morphology, an exceptional crystal structure, and enhanced light absorption, all of which contribute to accelerated PL quenching and charge transfer. Power conversion efficiency (PCE) was enhanced across all photovoltaic parameters through the use of larger granules in bulk-heterojunction solar cells, as opposed to undoped heterojunction solar cells. The PCE of the perovskite device with CH3NH3PbI3 base is 17.04 % at the optimal concentration of 6 mg/mL AgBiS2 NPs. These findings indicate that the doping of CH3NH3PbI3 perovskite thin films with AgBiS2 NPs is essential for the achievement of high crystallinity, a large particle size, and a high absorption coefficient. These properties are advantageous for the high-power conversion efficiency of solar cell applications.

CuIn (Se,Te)2 Absorbers With Bandgaps <1 eV for Bottom Cells in Tandem Applications

ABSTRACTThin‐film solar cells reach high efficiencies and have a low carbon footprint in production. Tandem solar cells have the potential to significantly increase the efficiency of this technology, where the bottom‐cell is generally composed of a Cu(In,Ga)Se2 absorber layer with bandgaps around 1 eV or higher. Here, we investigate CuIn(Se1 − xTex)2 absorber layers and solar cells with bandgaps below 1 eV, which will bring the benefit of an additional degree of freedom for designing current‐matched two‐terminal tandem devices. We report that CuIn(Se1 − xTex)2 thin films can be grown single phase by co‐evaporation and that the bandgap can be reduced to the optimum range (0.92–0.95 eV) for a bottom cell. From photoluminescence spectroscopy, it is found that no additional non‐radiative losses are introduced to the absorber when adding Te. However, losses occur in the final solar cell due to non‐optimized interfaces. Nevertheless, a device with 9% power conversion efficiency is demonstrated with a bandgap of 0.97 eV and , the highest efficiency so far for chalcopyrites with band gap <1 eV. Interface recombination is identified as a major recombination channel for larger Te contents. Thus, further efficiency improvements can be expected with improved absorber/buffer interfaces.

The DFT prediction of comprehensive properties of antiperovskites Mg6CX4 (X = S, Se, Te) and effects of defects and surface adsorption

It is important to search potential materials to meet ever-increasing demand in various fields. In order to understand the new hexagonal antiperovskites material Mg6CX4 (X=S, Se, Te), their mechanical, electronic and optical properties were studied based on density functional theory (DFT). The structural stability has been confirmed by the elastic constant criteria, formation energy, phonon dispersion spectra and ab-initio molecular dynamics (AIMD) simulation performed at 300K. Besides, the Poisson's ratios over 0.26 demonstrate the ductility of the studied materials. They all have direct electronic band structures with bandgaps of 0.977eV for Mg6CS4, 0.809eV for Mg6CSe4 and 1.274eV for Mg6CTe4, respectively. The calculated melting temperatures are all around 1000K, which indicates the potential for high-temperature application. Therefore, Mg6CTe4 fits most for absorber in solar cells due to its proper bandgap and dispersive band edge. The antiperovskites exhibit high and broad light absorption in visible and near ultraviolet region with absorption coefficient greater than 104cm-1, which inidcates a broad applicable prospect in optoelectronic field. Mg6CTe4 is also a candidate for efficient solid-state refrigeration due to its lowest thermal conductivity as 0.0046W/(K•m). The defect analysis suggest that oxygen defects are the most favorable and have complex effects on bandgaps. The high bandgap sensitivity to surface adsorbates implies potential application in gas detector.

Maximizing light absorption and photocurrent in organic solar cells by aligning intrinsic absorption peaks with Fabry-Perot resonances

We provide a physical interpretation of the mechanism by which maximum light absorption is achieved in organic solar cells (OSCs) through the tailoring of Fabry-Perot (FP) resonances. Overlapping the intrinsic absorption peaks of the active layer with the FP resonances in a planar OSC structure maximizes light absorption, leading to the highest short-circuit current density (JSC). The OSC with a 119 nm-thick active layer of PTB7-Th:IEICO-4F, where intrinsic absorption peaks occur at wavelengths of 715 nm and 885 nm, exhibits fundamental FP resonant modes at wavelengths of 500, 715, 750, and 850 nm. The strong electric field intensity generated by the FP resonance coincides with the intrinsic absorption peaks of the active layer at 715 nm and 885 nm, leading to an experimentally observed JSC of 26.50 mA/cm2. Optical admittance analyses are conducted to investigate the reduced reflection associated with enhanced light absorption. These results provide a deeper understanding of the fundamental mechanism for designing multilayer photonic and optoelectronic devices. This design principle is general and can be applied to various optoelectronic devices, such as photovoltaics, sensors, and photodetectors across a wide range of wavelengths.

Novel Tl2GeX6 (X=Cl,Br) Double Perovskites for Solar Cell, Optoelectronic, and Thermoelectric Applications: A DFT Investigation

This study aims to investigate the structural, mechanical, optical, electronic, and thermoelectric properties of novel double perovskites Tl2GeCl6 and Tl2GeBr6. The Quantum Espresso code was employed to perform the Density Functional Theory (DFT) calculation on the perovskites’ characteristics. The results indicated that both materials exhibit chemical and structural stability, with equilibrium lattice constants of 10.08 Å and 10.55 Å for Tl2GeCl6 and Tl2GeBr6, respectively. The calculated elastic parameters and elastic moduli data also demonstrated that the new double perovskites exhibit mechanical stability while the calculated electronic band structure and the density of states using the PBE functional indicated that the materials are semiconductors with energy gap values of 0.3 eV for Tl2GeBr6 and 1.72 eV for Tl2GeCl6, respectively. Using more accurate SCAN approximation, the energy gaps were refined to 0.53 eV for Tl2GeBr6 and 2.10 eV for Tl2GeCl6. Additionally, the calculated dielectric functions, extinction coefficient and absorption coefficients of Tl2GeCl6 and Tl2GeBr6 strongly suggest the exceptional optical response of these materials. Notably, Tl2GeBr6 is estimated to have a particularly strong visible-light absorption capacity, positioning it as a promising absorber for perovskite solar cells. These findings are also supported by the low reflectivity values observed. Finally, the analysis of their thermoelectric properties revealed the excellent thermoelectric properties of Tl2GeCl6 and Tl2GeBr6, as indicated by their high figures of merit, predicted to be 0.73 and 0.68 for the respective perovskites.

A comprehensive numerical study of bilayer SnSe/SnS absorber based solar cells

Herein, we present the simulation (using the SCAPS-1D program), of a bilayer absorber solar cell. First, we numerically studied the bilayer model using our experimentally observed parameters and investigated the results. The results from the bilayer absorber (SnSe/SnS) numerical analysis were then compared with a single (SnS and SnSe) absorber modeling. The optimized device with a bilayer absorber exhibited the highest performance, with a photo conversion efficiency (PCE) of 22.35%. In comparison, the single SnS and SnSe absorbers achieved a PCE of 14.79% and 13.69%. Furthermore, we compared this numerical study with our previous study having the same configuration. Although there was a significant difference in performance between the simulated and experimental studies, the outcomes of the fabricated devices exhibited similar trends to the simulations. Finally, we attempted to determine the key parameters responsible for the reduced performance in the experimental study.

Theoretical Optimization of an Earth-Abundant and Environmentally Friendly Photovoltaic Absorber Cu3PSe4 from First-Principles Study to Device Simulation.

To seek an earth-abundant and environmentally friendly absorber for thin-film solar cells, Cu3PSe4 is investigated by first-principles calculations and device simulations. We demonstrate that the compound has a suitable band gap width of 1.3 eV as well as a high sunlight absorption coefficient. However, drawbacks like small electron affinity, high hole concentration, large lattice mismatch with CdS, etc., are revealed, which may degrade the photovoltaic performance. To address those shortcomings, we propose (1) to optimize the carrier concentration by preparing the samples at low temperature and under a Cu-rich environment, (2) to replace the CdS buffer layer by a more suitable wide-gap semiconductor with smaller lattice mismatch, and (3) that the selected buffer layer should have small electron affinity in order to reduce the open-circuit voltage losses. After implementation of these optimization approaches, the device simulations demonstrate that the power conversion efficiency reaches 17.7% for a solar cell with the configuration Mo/Cu3PSe4/WS2/n-ZnO. The combination of first-principles calculations at the atomistic level and device simulations at the macroscopic level provides an appropriate approach to design ideal solar cells.

Enhanced Efficiency of Dye-Sensitized Solar Cells by Controlled Co-Adsorption Self-Assembly of Dyes.

Single dyes typically exhibit limited light absorption in dye-sensitized solar cells (DSSCs). Thus, cosensitization using two or more dyes to enhance light-harvesting efficiency has been explored; however, the aggregation of dyes can adversely affect electron injection capabilities. This study focused on the design and synthesis of three dyes with a common carbazole donor for DSSCs: DZ102, TZ101, and JM102. JM102 broadens the absorption spectrum by replacing the benzoic acid electron acceptor of TZ101 with acetylenic benzoic acid. A cosensitized DSSC device based on CO-1 [DZ102:TZ101 = 1:1 (50 μM:50 μM)] achieved a short-circuit current density of 19.4 mA/cm2 and a power conversion efficiency of 10.9%. For the first time, the molecular interactions between the dyes in the photoanode were demonstrated using cyclic voltammetry, which revealed the presence of intermolecular forces. Adsorption kinetics further indicated that these forces promoted the self-assembly of dyes during adsorption, which resulted in a cosensitization adsorption amount greater than the sum of the individual dye adsorptions. This study provides novel insights into the selection of cosensitizing dyes for DSSCs.

Design of Graphene-Based Core/Shell Nanoparticles to Enhance the Absorption of Thin Film Solar Cells

Design of Graphene-Based Core/Shell Nanoparticles to Enhance the Absorption of Thin Film Solar Cells

Photon shifting and trapping in perovskite solar cells for improved efficiency and stability

Advanced light management techniques can enhance the sunlight absorption of perovskite solar cells (PSCs). When located at the front, they may act as a UV barrier, which is paramount for protecting the perovskite layer against UV-enabled degradation. Although it was recently shown that photonic structures such as Escher-like patterns could approach the theoretical Lambertian-limit of light trapping, it remains challenging to also implement UV protection properties for these diffractive structures while maintaining broadband absorption gains. Here, we propose a checkerboard (CB) tile pattern with designated UV photon conversion capability. Through a combined optical and electrical modeling approach, this photonic structure can increase photocurrent and power conversion efficiency in ultrathin PSCs by 25.9% and 28.2%, respectively. We further introduce a luminescent down-shifting encapsulant that converts the UV irradiation into Visible photons matching the solar cell absorption spectrum. To this end, experimentally obtained absorption and emission profiles of state-of-the-art down-shifting materials (i.e., lanthanide-based organic-inorganic hybrids) are used to predict potential gains from harnessing the UV energy. We demonstrate that at least 94% of the impinging UV radiation can be effectively converted into the Visible spectral range. Photonic protection from high-energy photons contributes to the market deployment of perovskite solar cell technology, and may become crucial for Space applications under AM0 illumination. By combining light trapping with luminescent downshifting layers, this work unravels a potential photonic solution to overcome UV degradation in PSCs while circumventing optical losses in ultrathin cells, thus improving both performance and stability.

Performance optimization of (FA)2BiCuI6 perovskite solar cells using transport layer integration

The double-halide perovskite (FA)₂BiCuI₆ has been identified as a key material for enhancing the light absorption in perovskite solar cells (PSCs). In a device structure composed of FTO/STO/(FA)₂BiCuI₆/Spiro-OMeTAD/Au, notable photovoltaic (PV) performance has been achieved. Sulfur-doped tin oxide (STO) is utilized as the electron transport layer (ETL), (FA)₂BiCuI₆ serves as the absorber, and Spiro-OMeTAD functions as the hole transport layer (HTL), with gold (Au) and fluorine-doped tin oxide (FTO) acting as the contacts. Through optimization using the Solar Cell Capacitance Simulator (SCAPS-1D), the thicknesses of the absorber, HTL, ETL, and FTO were set to 1000 nm, 150 nm, 150 nm, and 100 nm, respectively, with the device operating at 300 K. This setup demonstrated high performance under the AM1.5 G spectrum, yielding an open-circuit voltage (VOC) of 1.02 V, a short-circuit current density (JSC) of 25.6 mA/cm², a fill factor (FF) of 87.76 %, and a power conversion efficiency (PCE) of 22.97 %. The device also exhibited a quantum efficiency (QE) of approximately 99.30 % within the visible light range.

Boosting the effectiveness of a cutting-edge Ca3NCl3 perovskite solar cell by fine-tuning the hole transport layer

Ca3NCl3 has unique electrical and optical properties and shows great potential as an absorber for solar cells, offering a promising solution for enhancing efficiency and reducing costs. To determine the best device layout, this study uses a device combination of Ag/FTO/ETL/Ca3NCl3/HTL/Ni, including seven HTLs and one ETL with the SCAPS-1D simulator. To improve device configuration, consider variables including thickness, temperature, doping density, defect density, and series and shunt resistance. After optimizing device parameters, the Ag/FTO/SnS2/Ca3NCl3/MoO3/Ni device outperformed the other 6-HTLs (Cu2O, CuI, CuSCN, NiO, CuSbS2, and P3HT) based devices with a power conversion efficiency (PCE) of 28.13 %, an open circuit current (VOC) of 1.36 V, a short circuit current density (JSC) of 22.892 mA/cm2, and a fill factor (FF) of 90.36 %. This proposed solar cell has exceptional performance compared to conventional thin-film solar cells, highlighting Ca3NCl3 as an appealing solution for solar energy systems while reducing toxicity issues.

A DFT investigation of Ti-substituted [formula omitted] for tailored photovoltaic properties

Transition Metal Chalcogenide Perovskites (TMCP) have been in the spotlight due to their exceptional optoelectronic properties. CaZrS3 is one among them with an experimental bandgap of 1.90 eV. If its bandgap is tuned to lower values, it can be employed in additional photovoltaic applications, such as solar cell absorbers. In this work, the transition metal element Zr in CaZrS3 is substituted with Ti atoms in different proportions and the optoelectronic properties are investigated using Density Functional Theory (DFT). The optoelectronic calculations are all done using the DFT+U method including the spin–orbit coupling. With substitutional alloying, we successfully tuned the energy gap from 1.91 eV to 1.18 eV and the photovoltaic properties were also observed to be modified. For the substituted CaZr1−xTixS3 samples, large birefringence is observed. This indicates enhancement in optical anisotropy via substitutional alloying which is significant in both linear and nonlinear optoelectronic applications like polarizers, wave plates etc.

Numerical analysis and device modelling of a lead-free Sr3PI3/Sr3SbI3 double absorber solar cell for enhanced efficiency.

Halide perovskites are the most promising options for extremely efficient solar absorbers in the field of photovoltaic (PV) technology because of their remarkable optical qualities, increased efficiency, lightweight design, and affordability. This work examines the analysis of a dual-absorber solar device that uses Sr3SbI3 as the bottom absorber layer and Sr3PI3 as the top absorber layer of an inorganic perovskite through the SCAPS-1D platform. The device architecture includes ZnSe as the electron transport layer (ETL), while the active layer consists of Sr3PI3 and Sr3SbI3 with precise bandgap values. The bandgap value of Sr3SbI3 is 1.307 eV and Sr3PI3 is 1.258 eV. By employing double-graded materials of Sr3PI3/Sr3SbI3, the study achieves an optimized efficiency of up to 34.13% with a V OC of 1.09 V, FF of 87.29%, and J SC of 35.61 mA cm-2. The simulation explores the influence of absorber layer thickness, doping level, and defect density on electrical properties like efficiency, short-circuit current, open-circuit voltage, and fill factor. It also examines variations in temperature and assesses series and shunt resistances in addition to electrical factors. The simulation's output offers valuable insights and suggestions for designing and developing double-absorber solar cells.

Computational Investigation of Structural, Electronic and Optical Properties of Ternary Chalcogenide TLGaQ2 Monoclinic Compounds: a First Principle Study

Purpose: This paper aim to investigate and predict by simulation the impact of the substitution of Q-site atom (Q꞊S, Se) on the TIGaQ2 monoclinic compounds for the first time, along the three main polarizations of the incident wave directions [100], [010] and [001]. Theoretical Framework: This study focuses mainly on ternary chalcogenide compounds TlGaQ2 (Q= S, Se) from ABQ2 family to highlight the objective resources aimed at promising prospects offered for them. Design/Methodology/Approach: A series of ab-initio calculations based on the (PW+PP) method within the density functional theory DFT framework were carried out with CASTEP code for the simulation of their physical properties (structural, electronic-optical). The exchange correlation potential was treated within the generalized gradient approximation (GGA) implemented in the CASTEP code and expressed by the PBE functional. Findings: The equilibrium lattice parameters are in good agreement with the available experimental results. The calculated band structure shows that are direct bandgap semiconductor nature 1.92eV (1.41eV) for TlGaS2 and TlGaSe2 respectively with a great potential for photovoltaic solar cell absorber materials. A set of optical parameters were calculated including the complex dielectric function, the reflective index, reflectivity, the absorption coefficient and loss function. The optical properties obtained revealed very interesting optical properties exhibiting strong optical absorption in UV range up to (~2x105cm-1) for both compounds making them appropriate for photovoltaic solar-cell absorber materials. Furthermore, low reflectivity and energy loss function are shown within in the visible and ultraviolet energy range, allowing them to be promising materials in several optoelectronics applications likes photosensitive devices. Implications: All these findings results show a successful accurately prediction for chalcogenide materials behavior and will be helpful for future studies allowing a better understanding of their potential applications in modern photovoltaic technologies as well as within UV ranges for optoelectronics applications.

A new design and optimization of SnSe-based dual absorber solar cell with efficiency above 28%

A new design and optimization of SnSe-based dual absorber solar cell with efficiency above 28%

Thermally Stable Perovskite Solar Cells with Fluoropolymer Coating

Halide perovskites are promising as the light absorbers of solar cells with efficient solar power conversion. However, why the degradation of perovskite solar cells (PSCs), especially at high temperatures, happens has not been completely understood to date. Herein, it is shown that evaporation of 4‐tert‐butylpyridine (4‐tBP) from the hole transport layer (HTL) of 2,2',7,7'‐tetrakis(N,N‐di‐p‐methoxyphenylamino)‐9,9'‐spirobifluorene (spiro‐OMeTAD) is one of possible degradation mechanisms in PSCs at a high temperature of 85 °C. In fresh PSCs, the chemical doping of the spiro‐OMeTAD HTL with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is not so efficient because of the formation of a LiTFSI:4‐tBP complex in the HTL. When PSCs are placed at 85 °C, 4‐tBP gradually evaporates from the HTL, resulting in the dissociation of the LiTFSI:4‐tBP complex. This 4‐tBP evaporation enhances the chemical doping of spiro‐OMeTAD by LiTFSI and makes the hole transport level of the spiro‐OMeTAD HTL deeper, thereby impeding hole extraction at the perovskite/spiro‐OMeTAD/Au interfaces. Herein, the 4‐tBP evaporation by covering PSCs with a fluoro‐polymer CYTOP layer, significantly improving the high‐temperature durability of PSCs, is suppressed. The basic understanding obtained in this study would help promote the spread of more thermally durable PSC products in the future.

Prediction of Frequency-Dependent Optical Spectrum for Solid Materials: A Multioutput and Multifidelity Machine Learning Approach.

The frequency-dependent optical spectrum is pivotal for a broad range of applications from material characterization to optoelectronics and energy harvesting. Data-driven surrogate models, trained on density functional theory (DFT) data, have effectively alleviated the scalability limitations of DFT while preserving its chemical accuracy, expediting material discovery. However, prevailing machine learning (ML) efforts often focus on scalar properties such as the band gap, overlooking the complexities of optical spectra. In this work, we employ deep graph neural networks (GNNs) to predict the frequency-dependent complex-valued dielectric function across the infrared, visible, and ultraviolet spectra directly from the crystal structures. We explore multiple architectures for the spectral multioutput representation of the dielectric function and utilize various multifidelity learning strategies, such as transfer learning and fidelity embedding, to address the challenges associated with the scarcity of high-fidelity DFT data. Additionally, we model key solar cell absorption efficiency metrics, demonstrating that learning these parameters is enhanced when integrated through a learning bias within the learning of the frequency-dependent absorption coefficient. This study demonstrates that leveraging multioutput and multifidelity ML techniques enables accurate predictions of optical spectra from crystal structures, providing a versatile tool for rapidly screening materials for optoelectronics, optical sensing, and solar energy applications across an extensive frequency spectrum.