Solar Cells Research Articles

Enhanced Efficiency of Dye-Sensitized Solar Cells Using Nitrogen-Titanium Dioxide Composites and Optimized Azo Dye Mixtures

In response to the increasing global energy demand, developing cost-effective and reliable renewable energy sources is crucial. Dye-Sensitized Solar Cells (DSSCs) have emerged as a promising alternative due to their low production cost, flexibility, and capability to operate under diffuse sunlight. This study aims to enhance the efficiency of DSSCs by incorporating Nitrogen-Titanium Dioxide (N-TiO2) composites synthesized via the Sol-Gel method [1]. The DSSCs were constructed using N-TiO2 composites in conjunction with VC, RP, and RM azo dyes. Nitrogen in the TiO2 matrix effectively reduced the band gap, leading to improved light absorption. The presence of Nitrogen dopants is expected to introduce additional energy levels within the TiO2 bandgap, enhancing light absorption and charge carrier separation, which are crucial factors for improved DSSC performance [2,3]. The current-voltage (I-V) characteristics of the DSSCs revealed significant variations in key performance metrics, including short circuit current (Isc), fill factor, and power conversion efficiency. Specifically, DSSCs utilizing N-TiO2 with VC-RP dye mixture achieved a higher efficiency of 0.349%, an Isc of 0.85 mA, and a fill factor of 44.59%, with Rs and Rsh values of 328.13Ω and 1637.18Ω, respectively [4]. These results underscore the potential of N-TiO2 composites, particularly when paired with optimized dye mixtures, to significantly enhance the electronic properties and overall efficiency of DSSCs.

Dual-Coated Antireflective Film for Flexible and Robust Multi-Environmental Optoelectronic Applications.

Artificial antireflective nanostructured surfaces, inspired by moth eyes, effectively reduce optical losses at interfaces, offering significant advantages in enhancing optical performance in various optoelectronic applications, including solar cells, light-emitting diodes, and cameras. However, their limited flexibility and low surface hardness constrain their broader use. In this study, we introduce a universal antireflective film by integrating nanostructures on both sides of a thin polycarbonate film. One side was thinly coated with Al2O3 for its high hardness, enhancing surface durability while maintaining flexibility. The opposite side was coated with SiO2 to optimize antireflective properties, making the film suitable for diverse environments (i.e., air, water, and adhesives). This dual-coating strategy resulted in a mechanically robust and flexible antireflective film with superior optical properties in various conditions. We demonstrated the universal capabilities of our antireflective film via optical simulations and experiments with the fabricated film in different environments.

Effect of Sulfurization Temperature on Properties of Cu2ZnSnS4 Thin Films and Diffusion of Ti Substrate Elements

The addition of flexible Cu2ZnSnS4 (CZTS) thin film solar cells to titanium (Ti) substrates is an attractive way to achieve the low-cost manufacturing of photovoltaics. Prior research has indicated that the appropriate diffusion of Ti elements can enhance the crystalline growth of CZTS films. However, the excessive diffusion of Ti has been shown to adversely affect the photovoltaic performance of CZTS photovoltaic devices. Therefore, it is essential to regulate the diffusion of Ti elements within CZTS thin films to optimize their photovoltaic properties. The tendency for Ti substrate elements to diffuse into CZTS films is also influenced by the activation energy associated with these Ti elements. The sulfurization temperature is posited to be a critical factor in modulating the diffusion and activation energy of Ti elements within CZTS thin films. Consequently, this research investigates the alteration of the sulfurization temperature of CZTS thin films in order to enhance the properties of these thin films and to examine the diffusion behavior of titanium elements. The results reveal that as the sulfurization temperature increases, the diffusion of Ti elements within the CZTS thin films initially increases, then decreases, and subsequently increases again. This pattern suggests that the diffusion of Ti elements is affected not only by the activation energy of the Ti elements but also by the defect hopping distance within the CZTS thin films. Notably, at a sulfurization temperature of 550 °C, the grains at the base of the CZTS thin film demonstrate an increased density, which is associated with a reduced defect hopping distance, thereby hindering the diffusion of Ti elements within the CZTS thin films. Furthermore, at this specific sulfurization temperature, the slope of the current–voltage (I–V) curve for the CZTS/Ti structure reaches its maximum, indicating optimal ohmic contact characteristics.

Application of improved Jellyfish search algorithm for 9-parameters cell extraction and GMPPT in PV systems

Optimization algorithms are essential tools used to address real-world problems through minimization or maximization processes. In the context of photovoltaic (PV) systems, various optimization algorithms have been employed to extract solar cell parameters using minimization techniques, and to identify the maximum power point (MPP) using maximization approaches. However, under partial shading conditions or during rapidly changing irradiance, many of these algorithms tend to get trapped in local minima, failing to locate the global maximum power point (GMPPT). This shortcoming leads to significant energy losses from PV cells. Similarly, the extraction of solar cell parameters is often compromised by the random search behavior and inadequate exploration and exploitation capabilities of many existing algorithms. The Jellyfish Search Optimization (JSO) algorithm is a recent, parameter-free method developed to tackle a wide range of optimization problems. Despite its innovative design, JSO is prone to premature convergence and exhibits a longer convergence time. To address these limitations, this paper proposes a modified version of the JSO algorithm, which integrates the state-of-the-art features of JSO with the Lévy flight characteristic from the cuckoo search algorithm. This combination aims to achieve a better balance between exploration and exploitation. To validate the effectiveness of the proposed Improved Jellyfish Search Optimization (IJSO) algorithm in PV systems, extensive experiments were conducted. These experiments included benchmarking with complex test functions, extracting cell parameters using various solar cell models, and maximizing energy output from PV systems under different environmental conditions. The results demonstrate that the proposed IJSO algorithm effectively enhances parameter extraction and global maximum power point tracking, making it a promising solution for optimizing energy extraction from PV cells in dynamic conditions.

Polymer Acceptor Copolymerized with Luminescent Unit for High‐Performance All‐Polymer Solar Cells with Low Non‐radiative Energy Loss

AbstractReduction of non‐radiative energy loss (ΔEnr) in all‐polymer solar cells (all‐PSCs) is crucially important for achieving high power conversion efficiencies (PCEs). Herein, an efficient strategy is reported to reduce the ΔEnr by introducing luminescent unit into the backbone of polymer acceptors. Compared to the device based on PM6:PYDT, the ΔEnr in all‐PSC based on PM6:PYDT‐CzP‐9 has decreased from 0.188 to 0.183 eV. This reduction is attributed to the improvement in electroluminescence external quantum efficiency (EQEEL). The PM6:PYDT‐CzP‐9 device has shown an 18% increase in EQEEL compared to the device based on PM6:PYDT (8.4 × 10−4 vs 7.1 × 10−4), demonstrating that the incorporation of luminescent unit in polymer acceptors is highly effective in enhancing the electroluminescence performance of all‐PSCs. As a result, the PM6:PYDT‐CzP‐9 device yielded a high VOC of 0.967 V, without the sacrifice of short‐circuit current density (23.42 mA cm−2) and fill factor (77.5%), leading to a high PCE of 17.55%.

Star-Shaped Molecules with a Triazine Core: (TD)DFT Investigation of Charge Transfer and Photovoltaic Properties of Organic Solar Cells

Star-Shaped Molecules with a Triazine Core: (TD)DFT Investigation of Charge Transfer and Photovoltaic Properties of Organic Solar Cells

Accelerated discovery of polymer donors for organic solar cells through machine learning: From library creation to performance forecasting

The design of novel polymer donors for organic solar cells has been a major research focus for decades, but discovering unique materials remains challenging due to the high cost of experimentation. In this study, machine learning models are employed to predict power conversion efficiency (PCE), Mordred descriptors are used for model training. Among the four machine learning models evaluated, the gradient boosting regressor emerged as the best-performing model. Additionally, a chemical library of polymer donors was generated and analyzed using various measures. 30 donors with highest PCE are selected and their synthetic accessibility is evaluated. Similarity analysis has indicated much resemblance in selected polymer donors.

Unveiling the potential of Cs2AgBiBr6 perovskites for next-generation see-through photovoltaics

Lead-free perovskite solar cells are strong contenders in the race for green and sustainable energy. Among these, cesium silver bismuth bromide (Cs2AgBiBr6) stands out, but its potential was hampered by the need for high-temperature processing, hindering its transition to scalable techniques. In this work, we present the feasibility of blade-coating deposition of Cs2AgBiBr6 layer. Thanks to the temperature control of the substrate during the process, we deposited uniform films at precise thickness enabling the fabrication of fully semitransparent devices with power conversion efficiencies (PCEs) of 3.07 % and 7.7 % under 1 sun and indoor light conditions, respectively. Furthermore, we evaluated important metrics for transparent photovoltaics such as Light Utilization Efficiency (LUE) and Color Rendering Index (CRI) of the devices by varying the Cs2AgBiBr6 thicknesses and the illumination conditions. The results showed LUEs at 1 Sun illumination of 1.1 % (1.5 %) and CRI of 71 (62.5) for 200 nm-thick and 400 nm-thick perovskite films, respectively. Finally, we evaluated the process scalability fabricating 6 cm2-sized semitransparent modules suitable for low-power electronics in Internet of Things field. This study opens the door to the development of non-hazardous, scalable, lead-free perovskite solar cells and modules suitable for integration into our everyday surroundings thanks to their see-through properties.

Understanding the Role of Organic Hole Transport Layers on Pinhole Blocking and Performance Improvement in Sb2Se3 Solar Cells

AbstractSb2Se3 is an emerging semiconductor which has shown promise for low‐cost photovoltaic applications. After successive record‐efficiencies using a range of device structures, spiro‐OMeTAD has emerged as the default hole transport material (HTM), however, the function of HTM layers remains poorly understood. Here, thin‐film Sb2Se3 solar cells are fabricated with which three organic HTM layers ‐ namely P3HT, PCDTBT, and spiro‐OMeTAD are investigated. By comparing these against one another, and to a reference device, their role in the device stack are clarified. These organic HTM layers are found to serve a dual purpose, increasing both the average and peak efficiency by simultaneously blocking pinholes and improving the band alignment at the back contact, with marginal differences in performance between the different HTMs. This produced a champion device of 7.44% using P3HT, resulting from an improvement in all performance parameters. A more complex processing route, run‐to‐run variability, and lower overall device performance compared to the other organics challenge the assumption that spiro‐OMeTAD is the optimal HTM for Sb2Se3 devices. A Schottky barrier at the Au‐Sb2Se3 contact despite the deep work function of gold implies Fermi level pinning due to a defective interface, which each of the organic HTMs are equally capable of alleviating.

Coupled In Situ Electrical and Optical Characterization to Assess the Accelerated Aging of Perovskite Solar Cells

While perovskite (PVK)‐based solar cells exhibit excellent efficiencies and require a relatively simple synthesis process, stability issues during operation severely limit their commercial development. Therefore, degradation studies have drawn much attention, but the plethoric literature highlights the complexity of the topic. Thus far, in most studies, pre‐ and postmortem analyses are performed and the system's performances before and after aging are compared, severely limiting the understanding of degradation pathways. By contrast, in situ characterization allows the degradation to be tracked in real time and the pathways to be fully explored. To this end, a coupled current–voltage (IV)–photoluminescence (PL) characterization bench is set up inside a climate chamber, allowing for the periodic acquisition of PL spectra and IV curves during accelerated aging. In this study, the International Summit on Organic Photovoltaic Stability protocol damp–heat test (65 °C, 85% relative humidity) is applied to several PVK solar cells with various transport layer combinations. By following the evolution kinetics of PL spectra and IV curves, insights into the nature of the degradation mechanisms are obtained. Notably, it becomes possible to distinguish performance losses due to degradation of the PVK absorber from those where extracting layers are the cause.

Selenium‐Rich Sb2(S,Se)3 Thin Films Deposited via Sequential Chemical Bath Deposition for High‐Efficiency Solar Cells

AbstractRecently, solution‐processed antimony sulfoselenide (Sb2(S,Se)3) thin films and solar cells have gained popularity and achieved impressive results. One of the most effective improvements is the chemical bath deposition (CBD) approach, which is gentle, highly adjustable, and scalable. However, development in alloyed Sb2(S,Se)3 using this process has been modest, with a power conversion efficiency (PCE) of roughly 8%. In this work, a sequential CBD deposition strategy is designed, introducing sulfur (S) or selenium (Se) sources at different stages of the CBD process to achieve high‐quality Sb2(S,Se)3 thin films and devices. Impressively, adding a moderate amount of sodium thiosulfate and thioacetamide as mixed sulfur sources during the CBD deposition of Sb2Se3 can produce Se‐rich Sb2(S,Se)3 films with high crystallinity, suitable bandgaps, low defect density, and favorable energy level alignment. With a short‐circuit current density (JSC) of 26.80 mA cm−2 and a fill factor (FF) of 65.89%, the solar cells with the FTO/CdS/Sb2(S,Se)3/Spiro‐OMeTAD/Au structure obtained an impressive PCE of 9.29%, the highest to date for Sb2(S,Se)3 solar cells manufactured with the CBD process. This study provides a feasible approach for enhancing the performance of CBD‐produced Sb2(S,Se)3 solar cells and offers new insights and techniques for the synthesis of other complex multicomponent thin films.

Simulation of the functionality of ZnO, TiO2 and Ta2O5, and MoO2 carrier selective contacts of GaAs0.99Bi0.01 nanowire-based solar cells

Abstract Photovoltaic performance of perpendicularly aligned GaAs0.99Bi0.01/CSC/ITO core-shell nanowire solar cell is thoroughly investigated in this simulation based theoretical study for both electron selective contact (ESC) and hole selective contact (HSC) as carrier selective contact (CSC) shell around GaAs0.99Bi0.01 core nanowire. The overall performance has been compared with radial PiN doped GaAs0.99Bi0.01 NWSC to mark the improvement caused by carrier selectivity. ZnO, TiO2, and Ta2O5 materials have been chosen as ESC material and MoO2 is chosen as HSC material in order to carry out this comparative study. We have thoroughly performed geometry optimization test over a wide range of periods in order to select the optimized ITO (Indium Tin Oxide) thickness for obtaining maximum photo current generation. The maximum short circuit photo current density (Jsc) of 38.76 mA/cm2 is obtained with ZnO coated nanowire solar cell (NWSC) for a pitch (P) of 400 nm and ITO shell thickness of 90 nm. For this optimized geometry, TiO2, Ta2O5 and MoO2 coated structures offered Jsc of 35.82 mA/cm2, 35.69 mA/cm2, and 35.27 mA/cm2 respectively and the uncoated NW generated Jsc of 31.15 mA/cm2. The planar structure without coating exhibits a Jsc of 24.86 mA/cm2, which is significantly lower than the nanostructured solar cells. Finally Lumerical 3D charge transport simulator is used to perform the electrical stimulation of ZnO coated structure, which offers maximum ideal Jsc. A detailed electrical performance analysis of GaAs0.99Bi0.01/CSC/ITO unit nanowire solar cell for ZnO, TiO2, Ta2O5 as ESC and MoO2 as HSC have also been covered in this article which reveals that ZnO as ESC possesses promising potential for designing highly efficient solar cells as it offers a photo conversion efficiency(PCE) of the order of 25% and open circuit voltage (Voc) even for very less minority carrier lifetime (Ʈn) 0.1 ns of GaAs0.99Bi0.01 and 1ps Ʈn of ZnO.

High efficiency homojunction tandem organic solar cells with all solution processable interconnect layer

In the field of organic photovoltaics, the power conversion efficiency of single junction solar cells continues to improve. However, tandem organic solar cells are poised to push the efficiency limits even further and offer a promising avenue for improving the performance of organic photovoltaic devices. This study reports the development of an all-solution processed interconnecting layer (ICL) based on ZnO NPs:PEI/PEI/PEDOT:PSS/2PACz for tandem solar cells. The PM6:BTP-eC9 active layer material was adjusted for its donor-to-acceptor (D/A) ratio and film thickness as the front and back sub-cells. The ICL exhibits favorable mechanical, electrical and optical properties. Through multidimensional modulation, the front and rear sub-cells have been optimized to obtain highly efficient homojunction tandem solar cells. The tandem solar cell has a structure of indium tin oxide (ITO)/PEDOT:PSS/2PACz/active layer/ICL/active layer/PNDIT-F3N/Ag. This optimization resulted in a power conversion efficiency (PCE) of 19.9 %, which is the highest reported efficiency for homojunction tandem organic solar cells to date. Our research demonstrates that the PCE of homojunction tandem cells can be significantly improved by careful design of the interconnecting layers and optimization of the donor-to-acceptor (D/A) ratio. This strategy may provide guidance for further improvements in homojunction tandem cells.

Surface Matrix-Mediated Cation Exchange of Perovskite Quantum Dots for Efficient Solar Cells.

Cesium-formamidinium lead triiodide perovskite quantum dot (CsxFA1-xPbI3 PQD) is very promising for photovoltaic applications due to its good phase stability and outstanding optoelectronic properties. However, achieving the CsxFA1-xPbI3 PQDs with tunable compositions and robust surface matrix remains a challenge. Here, the surface matrix-mediated cation exchange of PQDs is proposed, in which a bi-functional molecule, tetrafluoroborate methylammonium (FABF4), is applied for the cation exchange and stabilizing surface matrix of PQDs. The results reveal that the FA+ of FABF4 molecules could exchange the Cs+ of CsPbI3 PQDs forming alloy CsxFA1-xPbI3 PQDs, allowing to tune the spectroscopies of PQDs. Meanwhile, the BF4- of FABF4 molecules can effectively stabilize the surface lattice and substantially diminish the surface vacancies of PQDs, improving the phase stability and optoelectronic properties of PQDs. Consequently, CsxFA1-xPbI3 PQD solar cells deliver an efficiency of up to 17.49%, which is the highest value of CsxFA1-xPbI3 PQD solar cells. This work provided important design principles for the composition and surface matrix regulation of PQDs for high-performance solar cells or other optoelectronic devices.

Surface Matrix‐Mediated Cation Exchange of Perovskite Quantum Dots for Efficient Solar Cells

Cesium‐formamidinium lead triiodide perovskite quantum dot (CsxFA1‐xPbI3 PQD) is very promising for photovoltaic applications due to its good phase stability and outstanding optoelectronic properties. However, achieving the CsxFA1‐xPbI3 PQDs with tunable compositions and robust surface matrix remains a challenge. Here, the surface matrix‐mediated cation exchange of PQDs is proposed, in which a bi‐functional molecule, tetrafluoroborate methylammonium (FABF4), is applied for the cation exchange and stabilizing surface matrix of PQDs. The results reveal that the FA+ of FABF4 molecules could exchange the Cs+ of CsPbI3 PQDs forming alloy CsxFA1‐xPbI3 PQDs, allowing to tune the spectroscopies of PQDs. Meanwhile, the BF4‐ of FABF4 molecules can effectively stabilize the surface lattice and substantially diminish the surface vacancies of PQDs, improving the phase stability and optoelectronic properties of PQDs. Consequently, CsxFA1‐xPbI3 PQD solar cells deliver an efficiency of up to 17.49%, which is the highest value of CsxFA1‐xPbI3 PQD solar cells. This work provided important design principles for the composition and surface matrix regulation of PQDs for high‐performance solar cells or other optoelectronic devices.

Dye-Containing Polymers with π-Extened Diketopyrropyrrole Derivatives for Semi-Transparent Organic Photovoltaics.

Dye-containing polymers P1 (PEDPP-OT-BDT) and P2 (PEDPP-OT-BDTT) including a π-extended diketopyropyrrole (DPP) derivative and electron-rich thiophene fused ring units (4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b']dithiophene for P1 and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene for P2) were synthesized as narrow band gap dyes. A π-extended DPP (EDPP-OT-BrPh), fragment of the polymers P1 and P2, was obtained by extending the π-conjugation of DPP using Ru(III)-catalyzed C-H and N-H activation reported by Gońka et al. in 2019, exhibiting a high quantum yield (ϕem=0.84) and small HOMO-LUMO gap (Eg=1.69 eV) due to the spatial overlap of the HOMO and LUMO orbitals. The solubility of the π-extended DPP was improved by introducing four 2-octylthophene side chains around the periphery of the planer dye moiety, while maintaining the high planarity of the dye molecule, which is essential to the function of optoelectronic devices. As a result, P1 and P2, polymerized with the π-extended DPP and BDT derivatives, exhibit carrier mobility of approximately 10-5 cm2/Vs in organic field-effect transistors (OFETs). In bulk heterojunction (BHJ) solar cells with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), they demonstrate a power conversion efficiency (PCE) of 1.0 % with an average transmittance (AVTs) of around 60 %.

Facile Synthesis, Sintering, and Optical Properties of Single-Nanometer-Scale SnO2 Particles with a Pyrrolidone Derivative for Photovoltaic Applications

We investigate the preparation of mesoscopic SnO2 nanoparticulate films using a Sn(IV) hydrate salt combined with a liquid pyrrolidone derivative to form a homogeneous precursor mixture for functional SnO2 nanomaterials. We demonstrate that N-methyl-2-pyrrolidone (NMP) plays a crucial role in forming uniform SnO2 films by both stabilizing the hydrolysis products of Sn(IV) sources and acting as a base liquid during nanoparticle growth. The hydrolysis of Sn(IV) was controlled by adjusting the reaction temperature to as low as 110 °C for 48 h. High-resolution TEM analysis revealed that highly crystalline SnO2 nanoparticles, approximately 3–5 nm in size, were formed. The SnO2 nanoparticles were deposited onto F-doped SnO2 glass and converted into dense particle films through heat treatments at 400 °C and 500 °C. This pyrrolidone-based nanoparticle synthesis enabled the production of not only crystallized SnO2 but also transparent and uniform films, most importantly by controlling the slow hydrolysis of Sn(IV) and polycondensation only with those two chemicals. These findings offer valuable insights for developing stable and uniform electron transport layers of SnO2 in mesoscopic solar cells, such as perovskite solar cells.

Output power analysis of low concentrated solar cells with fresnel lens optics

In this work, we introduce a П-shaped LCPV which works with a simple single-axis solar tracking system. The simulation of the П-shaped LCPV was made on COMSOL Multiphysics and output power of the LCPV was modeled and compared with other PV, LCPV systems using predicted optical efficiency at different incidence angles by regression methods such as XGBoost regression, Linear Regression, Support Vector Regression, Decision Tree Regression, Random Forest Regression. The most effective one was XGBoost regression with accuracy of 91.23931 %. The П-shaped LCPV generates 2.2 times more energy than the fixed nine-solar cell panel per a day. Using nine solar cells and the designed optics allows the system to operate well at wider incidence angles using a single-axis solar tracking system which rotates the system only 4 times a day. The П-shaped LCPV is less complex and cheaper than an ordinary Fresnel lens-based LCPV.

In-situ and ex-situ preparation of Bi2S3 on the BiVO4/TiO2 to construct Bi2S3/BiVO4/TiO2 heterojunction for efficient Cr(VI) reduction

The environmentally friendly and rapid removal of hexavalent chromium (Cr(VI)) from wastewater has garnered significant attention, driven by the severe acute toxicity and carcinogenic properties associated with Cr(VI). The design and synthesis of heterojunctions are recognized as effective solutions for enhancing the photocatalytic performance of TiO2 based materials. BiVO4/TiO2 and Bi2S3/BiVO4/TiO2 composite films (BVT) were prepared via a simple hydrothermal method. The influence of Bi2S3 preparation methods (In-situ and Ex-situ) on the morphology, structure and properties of BVT was studied. The relative crystallinity of TiO2, BiVO4/TiO2, BVT(In-situ) and BVT(Ex-situ) were 50 %, 62 %, 72 % and 92 %, respectively. SEM shows that the morphology of Bi2S3 in BVT(In-situ) was nanoribbon and that of Bi2S3 in BVT(Ex-situ) was radioactive sphere. Compared with pure TiO2 and BiVO4/TiO2, the light absorption range of BVT composite material has been expanded from the ultraviolet light region to the visible region, the bandgap has been significantly narrowed, and the photocurrent density has been increased. The BVT(In-situ) shows stronger photoelectrical performance and reduction efficiency of Cr (VI) compared to BVT(Ex-situ), reaching 93.9 %. The photocatalytic reaction rate of BVT(In-situ) and BVT(Ex-situ) are 0.0291 min−1 and 0.0266 min−1, respectively. Density functional theory (DFT) calculations indicate that the work function of BiVO4 is higher than that of Bi2S3, and electrons will transfer from Bi2S3 to BiVO4 at the heterojunction interface. The BVT(In-situ) heterojunction constructed in this experiment greatly improves the separation and transport efficiency of photo-generated carriers, laying the foundation for the wide application of BVT heterojunction in the field of optoelectronics and providing a strategy for photocatalytic reduction of Cr(VI). The BVT(In-situ) with FTO conductive glass, it also can be applied to photovoltaic fields such as solar cells, photocatalysis and photodetectors.

A strategy for achieving high-performance single layer polymer photodetectors through dark current reduction using PMMA additives

Suppressing dark current density is crucial for optimizing the performance of organic photodetectors (PDs), particularly in terms of detectivity (D∗) and linear dynamic range (LDR). Organic PDs often utilize the bulk heterojunction structure of organic solar cells to significantly increase photocurrent. However, unlike solar cells, which are unaffected by dark current, photodetectors' performance is substantially limited by it. The interconnected network of bulk heterojunctions leads to a noticeable increase in dark current, thus degrading device performance. Typically, reducing dark current involves adding a modification layer or using multilayer planar heterojunctions, which effectively reduce dark current but often delay response speed and complicate manufacturing. This study presents an alternative approach by incorporating a small concentration of PMMA into single-layer polymer photodetectors, significantly reducing dark current without affecting photocurrent. For this single-layer polymer PD, an ultra-low dark current density of 1.25 × 10−8 A/cm2, a high Dsh∗ of 2.74 × 1012 Jones, an LDR of 120.5 dB, and a fast response time with 1.6 μs were achieved. The capacitance-voltage (C-V), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and atomic force microscopy (AFM) measurements revealed that the PMMA additive reduces internal defects, increases bulk resistance, optimizes phase separation, and enhances carrier transport efficiency. The improved device performances are attributed to a more efficient vertical arrangement of the donor-acceptor interface and carrier channels, thus reducing carrier recombination loss. These findings offer a new direction for fabricating high-performance single-layer photodetectors.