Search Results (20)

Perovskite solar cells (PSCs) have emerged as a promising contender in photovoltaics, owing to their rapidly advancing power conversion efficiencies (PCEs) and compatibility with low-temperature solution processing techniques. Single-junction architectures reveal inherent limitations imposed by the Shockley–Queisser (SQ) limit, motivating adoption of a dual-absorber structure comprising Cs₄CuSb₂Cl₁₂ (CCSC) and Cs₂TiI₆ (CTI)—lead-free perovskite derivatives valued for environmental benignity and intrinsic stability. Comprehensive theoretical screening of 26 electron/hole transport layer (ETL/HTL) candidates identified SrTiO₃ (STO) and CuSCN as optimal charge transport materials, producing an initial simulated PCE of 16.27%. Subsequent theoretical optimization of key parameters—including bulk and interface defect densities, band gap, layer thickness, and electrode materials—culminated in a simulated PCE of 30.86%. Incorporating quantifiable practical constraints, including radiative recombination, resistance, and FTO reflection, revised simulated efficiency to 26.60%, while qualitative analysis of additional factors follows later. Furthermore, comparing multiple algorithms within this theoretical framework demonstrated eXtreme Gradient Boosting (XGBoost) possesses superior predictive capability, identifying CTI defect density as the dominant impact on PCE—thereby underscoring its critical role in analogous architectures and offering optimization guidance for experimental studies. Collectively, this theoretical research delineates a viable pathway toward developing stable, environmentally sustainable PSCs with high properties. Full article

Ultraviolet (UV) and blue-light photodetectors are vital in environmental monitoring, medical and biomedical applications, optical communications, and security and anti-counterfeiting technologies. However, conventional silicon-based devices suffer from limited sensitivity to short-wavelength light due to their narrow indirect bandgap. In this study, we investigate the influence of precursor concentration on the structural, optical, and photoresponse characteristics of nanostructured CdS thin films synthesized via chemical bath deposition. Among the CdS samples prepared at different precursor concentrations, the best photoresponsivity of 21.1 mA/W was obtained at 2 M concentration. Subsequently, a p–n heterojunction photodetector was fabricated by integrating a spin-coated CuSCN layer with the optimized CdS nanostructure. The resulting device exhibited pronounced rectifying behavior with a rectification ratio of ~750 and an ideality factor of 1.39. Under illumination and a 5 V bias, the photodetector achieved an exceptional responsivity exceeding 10⁴ A/W in the UV region—over six orders of magnitude higher than that of CdS-based metal–semiconductor–metal devices. This remarkable enhancement is attributed to the improved light absorption, efficient charge separation, and enhanced hole transport enabled by CuSCN incorporation and heterojunction formation. These findings present a cost-effective, solution-processed approach to fabricating high-responsivity nanostructured photodetectors, promising for future applications in smart healthcare, environmental surveillance, and consumer electronics. Full article

This study proposed a novel perovskite/silicon heterojunction (SHJ) tandem device structure without an interlayer, represented as ITO/NiO/perovskite/SnO₂/MoO_X/i-a-Si:H/n-c-Si/i-a-Si:H/n-a-Si:H/Ag, which was investigated by Silvaco TCAD software. The recombination layer in this structure comprises the carrier transport layers of SnO₂ and MoO_X, where MoO_X serves dual functions, acting as the emitter for the SHJ bottom cell and as part of the recombination layer in the tandem cell. First, the effects of different recombination layers are analyzed, and the SnO₂/MoO_X layer demonstrates the best performance. Then, we systematically investigated the impact of the carrier concentration, interface defect density, thicknesses of the SnO₂/MoO_X layer, different hole transport layers (HTLs) for the top cell, absorption layer thicknesses, and perovskite defect density on device performance. The optimal carrier concentration in the recombination layer should exceed 5 × 10¹⁹ cm⁻³, the interface defect density should be below 1 × 10¹⁶ cm⁻², and the thicknesses of SnO₂/MoO_X should be kept at 20 nm/20 nm. CuSCN has been found to be the optimal HTL for the top cell. When the silicon absorption layer is 200 μm, the perovskite layer thickness is 470 nm, and the defect density of the perovskite layer is 10¹¹ cm⁻³, the planar structure can achieve the best performance of 32.56%. Finally, we studied the effect of surface texturing on the SHJ bottom cell, achieving a power conversion efficiency of 35.31% for the tandem cell. Our simulation results suggest that the simplified perovskite/SHJ tandem solar cell with a dual-functional MoO_X layer has the potential to provide a viable pathway for developing high-efficiency tandem devices. Full article

Perovskite solar cells (PSCs) are regarded as extremely efficient and have significant potential for upcoming photovoltaic technologies due to their excellent optoelectronic properties. However, a few obstacles, which include the instability and high costs of production of lead-based PSCs, hinder their commercialization. In this study, the performance of a solar cell with a configuration of FTO/CdS/BaZrS₃/HTL/Ir was optimized by varying the thickness of the perovskite layer, the hole transport layer, the temperature, the electron transport layer (ETL)’s defect density, the absorber defect density, the energy band, and the work function for back contact. Various hole transport layers (HTLs), including Cu₂O, CuSCN, P3HT, and PEDOT:PSS, were assessed to select the best materials that would achieve high performance and stability in PSC devices. At optimal levels, PEDOT:PSS reached a maximum power conversion efficiency (PCE) of 18.50%, while P3HT, CuSCN, and Cu₂O exhibited a PCE of 5.81, 10.73, and 9.80%, respectively. The high performance exhibited by PEDOT:PSS was attributed to better band alignment between the absorber and the PEDOT:PSS, and, thus, a low recombination of photogenerated charges. The other photovoltaic parameters for the best device were a short-circuit current density (J_sc) of 23.46 mA cm⁻², an open-circuit voltage (V_oc) of 8.86 (V), and a fill factor (FF) of 8.90%. This study highlights the potential of chalcogenide-based PSCs as an efficient and stable alternative to traditional lead-based solar cells, with successful optimization paving the way for future research on eco-friendly materials and scalable production methods. Full article

Antimony selenide (Sb₂Se₃) shows promise for photovoltaics due to its favorable properties and low toxicity. However, current Sb₂Se₃ solar cells exhibit efficiencies significantly below their theoretical limits, primarily due to interface recombination and non-optimal device architectures. This study presents a comprehensive numerical investigation of Sb₂Se₃ thin-film solar cells using SCAPS-1D simulation software, focusing on device architecture optimization and interface engineering. We systematically analyzed device configurations (substrate and superstrate), hole-transport layer (HTL) materials (including NiOx, CZTS, Cu₂O, CuO, CuI, CuSCN, CZ-TA, and Spiro-OMeTAD), layer thicknesses, carrier densities, and resistance effects. The substrate configuration with molybdenum back contact demonstrated superior performance compared with the superstrate design, primarily due to favorable energy band alignment at the Mo/Sb₂Se₃ interface. Among the investigated HTL materials, Cu₂O exhibited optimal performance with minimal valence-band offset, achieving maximum efficiency at 0.06 μm thickness. Device optimization revealed critical parameters: series resistance should be minimized to 0–5 Ω-cm² while maintaining shunt resistance above 2000 Ω-cm². The optimized Mo/Cu₂O(0.06 μm)/Sb₂Se₃/CdS/i-ZnO/ITO/Al structure achieved a remarkable power conversion efficiency (PCE) of 21.68%, representing a significant improvement from 14.23% in conventional cells without HTL. This study provides crucial insights for the practical development of high-efficiency Sb₂Se₃ solar cells, demonstrating the significant impact of device architecture optimization and interface engineering on overall performance. Full article

Copper(I) thiocyanate (CuSCN) is considered an efficient HTL of low cost and with high stability in perovskite solar cells (PSCs). However, the diethyl sulfide solvent used for CuSCN preparation is known to cause damage to the underlying perovskite layer in n-i-p PSCs. Antisolvent treatment of CuSCN during spin-coating can effectively minimize interfacial interactions. However, the effects of antisolvent treatment are not sufficiently understood. In this study, the effects of five different antisolvents were investigated. Scanning electron microscopy and X-ray diffraction analyses showed that the antisolvent treatment improved the crystallinity of the CuSCN layer on the perovskite layer and reduced damage to the perovskite layer. However, X-ray and ultraviolet photoelectron spectroscopy analyses showed that antisolvent treatment did not affect the chemical bonds or electronic structures of CuSCN. As a result, the power conversion efficiency of the PSCs was increased from 14.72% for untreated CuSCN to 15.86% for ethyl-acetate-treated CuSCN. Full article

Conventional hole transport layer (HTL) Spiro-OMeTAD requires the addition of hygroscopic dopants due to its low conductivity and hole mobility, resulting in a high preparation cost and poor device stability. Cuprous thiocyanate (CuSCN) is a cost-effective alternative with a suitable energy structure and high hole mobility. However, CuSCN-based perovskite solar cells (PSCs) are affected by environmental factors, and the solvents of an HTL can potentially corrode the perovskite layer. In this study, a Co₃O₄/CuSCN/Co₃O₄ sandwich structure was proposed as an HTL for inorganic Cs₂PbI₂Cl₂/CsPbI_2.5Br_0.5 PSCs to address these issues. The Co₃O₄ layers can serve as buffer and encapsulation layers, protecting the perovskite layer from solvent-induced corrosion and enhancing hole mobility at the interface. Based on this sandwich structure, the photovoltaic performances of the Cs₂PbI₂Cl₂/CsPbI_2.5Br_0.5 PSCs are significantly improved, with the power conversion efficiency (PCE) increasing from 9.87% (without Co₃O₄) to 11.06%. Furthermore, the thermal stability of the devices is also significantly enhanced, retaining 80% of its initial PCE after 40 h of continuous aging at 60 °C. These results indicate that the Co₃O₄/CuSCN/Co₃O₄ sandwich structure can effectively mitigate the corrosion of the perovskite layer by solvents of an HTL and significantly improves the photovoltaic performance and thermal stability of devices. Full article

The electrical properties of solution-processed spinel nickel cobaltite (NiCo₂O₄) nanoparticulated-based metal oxide hole transporting layers are investigated using conductivity and Hall effect measurements. The mechanism of electrical conductivity of NiCo₂O₄-based electronic films as a function of temperature indicates hopping-type carrier transport. We show that NiCo₂O₄ hole transporting layers (HTLs) have suitable conductivity, low toxicity, and relatively low processing temperature, parameters that are important for electronic materials specifications of high performance and environmentally friendly emerging photovoltaics. As a proof of concept, NiCo₂O₄ and Cu-SCN surface-modified NiCo₂O₄ are incorporated as HTLs for non-fullerene acceptor Organic Photovoltaics (OPVs), and the photovoltaic performance results of the corresponding OPVs are presented. Full article

By an abrupt rise in the power conservation efficiency (PCE) of perovskite solar cells (PSCs) within a short span of time, the instability and toxicity of lead were raised as major hurdles in the path toward their commercialization. The usage of an inorganic lead-free CsSnI₃-based halide perovskite offers the advantages of enhancing the stability and degradation resistance of devices, reducing the cost of devices, and minimizing the recombination of generated carriers. The simulated standard device using a 1D simulator like solar cell capacitance simulator (SCAPS) with Spiro-OMeTAD hole transporting layer (HTL) at perovskite thickness of 330 nm is in good agreement with the previous experimental result (12.96%). By changing the perovskite thickness and work operating temperature, the maximum efficiency of 18.15% is calculated for standard devices at a perovskite thickness of 800 nm. Then, the effects of replacement of Spiro-OMeTAD with other HTLs including Cu₂O, CuI, CuSCN, CuSbS₂, Cu₂ZnSnSe₄, CBTS, CuO, MoS₂, MoO_x, MoO₃, PTAA, P₃HT, and PEDOT:PSS on photovoltaic characteristics were calculated. The device with Cu₂ZnSnSe₄ hole transport in the same condition shows the highest efficiency of 21.63%. The back contact also changed by considering different metals such as Ag, Cu, Fe, C, Au, W, Ni, Pd, Pt, and Se. The outcomes provide valuable insights into the efficiency improvement of CsSnI₃-based PSCs by Spiro-OMeTAD substitution with other HTLs, and back-contact modification upon the comprehensive analysis of 120 devices with different configurations. Full article

A hybrid tin-based (GA${}_{0.2}$FA${}_{0.78}$SnI${}_3$-1% EDAI${}_2$) perovskite solar cell (PSC) with a p-i-n inverted structure has been reported to pass all the rigorous standard tests successfully and achieve a certified power conversion efficiency (PCE) of 8.3%. Our previous numerical study showed that this PCE could be considerably increased to 24.1% by engineering and controlling the interfaces of the cell. The aim of the current study is to compare the performance of a conventional n-i-p structure with its inverted p-i-n analog quantitatively, and demonstrate that, by improving the conventional structure, it can achieve a PCE score approximately equal to the inverted p-i-n structure. To that end, the absorber layer was chosen to be GA${}_{0.2}$FA${}_{0.78}$SnI${}_3$-1% EDAI${}_2$, while four ETL (electron transport layer) materials (TiO${}_2$, WS${}_2$, SnO${}_2$, and ZnOS), and four HTL (hole transport layer) materials (PEDOT:PSS, Cu${}_2$O, CuSCN, and CuI) were considered. Most used ETL/HTL combinations have been rigorously investigated with the aim of finding the ultimate configuration, providing the highest photovoltaic properties. Additionally, the effect of the layers’ thicknesses and their doping concentrations were inspected, and their impact on the photovoltaic properties of the PSC was investigated. The optimized structure with CuI (copper iodide) as the HTL and ZnOS (zinc oxysulphide) as the ETL scored a PCE of 24.1%, which is comparable to the value found with the inverted structure (26%). The current numerical simulation on GA${}_{0.2}$FA${}_{0.78}$SnI${}_3$-1% EDAI${}_2$ could be considered as a milestone in its chances for commercial development. Full article

Antimony selenide (Sb₂Se₃) material has been brought into sharp focus in the solar cell field due to its remarkable performance in recent times. Solar cell efficiency increases daily because of the excellent properties of Sb₂Se₃ material and progressive optimisation of each layer, especially the hole-transporting layer (HTL); it suppresses the recombination of the back surface and increases the built-in potential and efficiency. In this work, we used Sb₂Se₃ as an absorber layer and compared the behaviour of typical hole transport materials (HTMs) (Spiro-OMeTAD, CuSCN, and CuI) and their influence on device performance. The Sb₂Se₃ photovoltaic model with different HTMs was studied by SCAPS (version 3.3.10) software. Efficiency is highly influenced by light source and intensity. Thickness and defect density of the Sb₂Se₃ layer, the work function of the back contact, and series and shunt resistances also play an essential role in the better execution of solar cells. The performance of the device is enhanced when the transmission percentage increases at the front contact. The metalwork function must be 5 eV to attain a highly efficient PV cell, and after optimisation, CuI is the best HTM with a 23.48% efficiency. Full article

The present research work represents the numerical study of the device performance of a lead-free Cs₂TiI_6−XBr_X-based mixed halide perovskite solar cell (PSC), where x = 1 to 5. The open circuit voltage (V_OC) and short circuit current (J_SC) in a generic TCO/electron transport layer (ETL)/absorbing layer/hole transfer layer (HTL) structure are the key parameters for analyzing the device performance. The entire simulation was conducted by a SCAPS-1D (solar cell capacitance simulator- one dimensional) simulator. An alternative FTO/CdS/Cs₂TiI_6−XBr_X/CuSCN/Ag solar cell architecture has been used and resulted in an optimized absorbing layer thickness at 0.5 µm thickness for the Cs₂TiBr₆, Cs₂TiI₁Br₅, Cs₂TiI₂Br₄, Cs₂TiI₃Br₃ and Cs₂TiI₄Br₂ absorbing materials and at 1.0 µm and 0.4 µm thickness for the Cs₂TiI₅Br₁ and Cs₂TiI₆ absorbing materials. The device temperature was optimized at 40 °C for the Cs₂TiBr₆, Cs₂TiI₁Br₅ and Cs₂TiI₂Br₄ absorbing layers and at 20 °C for the Cs₂TiI₃Br₃, Cs₂TiI₄Br₂, Cs₂TiI₅Br₁ and Cs₂TiI₆ absorbing layers. The defect density was optimized at 10¹⁰ (cm⁻³) for all the active layers. Full article

Li-doped CuSCN films of various compositions were applied as hole-transporting material (HTM) for mesoscopic perovskite solar cells (PSCs). Those films of ~60 nm thickness, spin-coated on the perovskite layer, exhibit significantly higher crystallinity and hole mobility compared with the pristine CuSCN films. Among them, 0.33% Li-doped CuSCN (Li0.33:CuSCN) shows the best performance as the HTM of mesoscopic PSC. Furthermore, by depositing a slight amount of PCPDTBT over the Li0.33:CuSCN layer, the V_OC was increased to 1.075 V, resulting in an average PCE of 20.24% and 20.65% for the champion device. These PCE and V_OC values are comparable to those of PSC using spiro-OMETAD (PCE: 20.61%, V_OC: 1.089 V). Such a remarkable increase can be attributed to the penetration of the PCPDTBT polymer into the grain boundaries of the Li0.33:CuSCN film, and to the interface with the perovskite layer, leading to the removal of defects on the perovskite surface by paving the non-contacting parts, as well as to the tight interconnection of the Li0.33:CuSCN grains. The PSC device with Li0.33:CuSCN showed a high long-term stability similar to that with bare CuSCN, and the introduction of PCPDTBT onto the perovskite/Li0.33:CuSCN further improved device stability, exhibiting 94% of the initial PCE after 100 days. Full article

Bismuth triiodide (BiI₃) is a particularly promising absorber material for inorganic thin-film solar cells due to its merits of nontoxicity and low cost. However, one key factor that limits the efficiency of BiI₃ solar cells is the film morphology, which is strongly correlated with the trap states of the BiI₃ film. Herein, we report a coordination engineering strategy by using Lewis base dimethyl sulfoxide (DMSO) to induce the formation of a stable BiI₃(DMSO)₂ complex for controlling the morphology of BiI₃ films. Density functional theory calculations further provide a theoretical framework for understanding the interaction of the BiI₃(DMSO)₂ complex with BiI₃. The obtained BiI₃(DMSO)₂ complex could assist the fabrication of highly uniform and pinhole-free films with preferred crystallographic orientation. This high-quality film enables reduced trap densities, a suppressed charge recombination, and improved carrier mobility. In addition, the use of copper(I) thiocyanate (CuSCN) as a hole transport layer improves the charge transport, enabling the realization of solar cells with a record power conversion efficiency of 1.80% and a champion fill factor of 51.5%. Our work deepens the insights into controlling the morphology of BiI₃ thin films through the coordination engineering strategy and paves the way toward further improving the photovoltaic performances of BiI₃ solar cells. Full article

Perovskite solar cells (PSCs) and dye-sensitized solar cells (DSCs) both represent promising strategies for the sustainable conversion of sunlight into electricity and fuels. However, a few flaws of current devices hinder the large-scale establishment of such technologies. On one hand, PSCs suffer from instabilities and undesired phenomena mostly linked to the perovskite/hole transport layer (HTL) interface. Most of the currently employed organic HTL (e.g., Spiro-OMeTAD) are supposed to contribute to the perovskite decomposition and to be responsible for charge recombination processes and polarization barriers. On the other hand, power conversion efficiencies (PCEs) of DSCs are still too low to compete with other conversion technologies. Tandem cells are built by assembling p-type and n-type DSCs in a cascade architecture and, since each dye absorbs on a different portion of the solar spectrum, the harvesting window is increased and the theoretical efficiency limit for a single chromophore (i.e., the Shockley–Queisser limit) is overcome. However, such a strategy is hindered by the lack of a p-type semiconductor with optimal photocathode features. Nickel oxide has been, by far, the first-choice inorganic p-type semiconductor for both PV technologies, but its toxicity and non-optimal features (e.g., too low open circuit voltage and the presence of trap states) call for alternatives. Herein, we study of three p-type semiconductors as possible alternative to NiO, namely CuI, CuSCN and Cu₂O. To this aim, we compare the structural and electronic features of the three materials by means of a unified theoretical approach based on the state-of-the art density functional theory (DFT). We focus on the calculation of their valence band edge energies and compare such values with those of two widely employed photo-absorbers, i.e., methylammonium lead iodide (MAPI) and the triple cation MAFACsPbBrI in PSCs and P1 and Y123 dyes in DSCs, given that the band alignment and the energy offset are crucial for the charge transport at the interfaces and have direct implications on the final efficiency. We dissect the effect a copper vacancy (i.e., intrinsic p-type doping) on the alignment pattern and rationalize it from both a structural and an electronic perspective. Our data show how defects can represent a crucial degree of freedom to control the driving force for hole injection in these devices. Full article