Performance Of Photovoltaic Devices Research Articles

Enhancing performance of organic photovoltaic and photodetector devices using non-atomically doped ZnO electrodes with superior optical properties

Enhancing performance of organic photovoltaic and photodetector devices using non-atomically doped ZnO electrodes with superior optical properties

Differential effects of MoO3 and MoO2 sacrificial layers on the J–V performance of Cu2ZnSn(S,Se)4 solar cells

The differential effect and mechanism of MoO2 and MoO3 sacrificial layers on enhancing the photovoltaic performance of CZTSSe devices have been compared, whereby the PCE increases from 7.51% to 9.58% (total area 0.21 cm2, Voc = 467 mV, Jsc = 32.3 mA cm−2, FF = 63.3%) under the assistance of MoO3.

SiW9Co3 @rGO composite-doping improved the crystallization and stability of a perovskite film for efficient photodetection.

The crystalline quality of perovskite films is a key factor that affects the performance of perovskite photovoltaic devices. Polyoxometalates can better match the energy levels of each layer in the devices through their own suitable energy level and band gap, and the good light absorption of POMs can also increase the mobility of photogenerated carriers in the devices. Moreover, POMs with Keggin-type structures can also improve the crystalline quality of perovskite films by eliminating defect sites, which can lead to better crystallization of perovskites with larger grains. In this study, we optimized the crystalline quality of a perovskite layer using the SiW9Co3@rGO composite prepared using POMs and graphene derivatives. XRD and SEM tests show that the crystallization degree of the perovskite layer was improved, the average grain size of which can reach up to 1222.92 nm, which is nearly four times higher than that of a blank perovskite. The photoresponse current of a SiW9Co3@rGO-doped photodetector can reach to 43.94 μA, which is about 226% higher than that of an undoped device. At the same time, the addition of the composite can improve the stability of photodetectors because of the special network structure of graphene. Photodetectors doped with SiW9Co3@rGO can still maintain more than 90% of their high performance for a month. This study proves that POM-based composites have good application prospects in the field of photovoltaic devices.

Simulation of the Effects of Geometry on Performance of Luminescent Solar Concentrator Photovoltaic Devices

Simulation of the Effects of Geometry on Performance of Luminescent Solar Concentrator Photovoltaic Devices

Improving the performance of kesterite solar cells by solution germanium alloying.

Cation substitution is an effective strategy to regulate the defects/electronic properties of kesterite Cu2ZnSn(S,Se)4 (CZTSSe) absorbers and improve the device photovoltaic performance. Here, we report Ge alloying kesterite Cu2Zn(Sn,Ge)(S,Se)4 (CZTGSSe) via a solution approach. The results demonstrate that the same chemical reaction of Ge4+ to Sn4+ ensures homogeneous Ge incorporation in the whole range of concentrations (from 0 to unit). Ge alloying promotes grain growth and linearly enlarges the absorber band gap by solely raising the conduction band minimum, which maintains a "spike" conduction band offset at the heterojunction interface until 15% alloying concentration and thus facilitates effective charge carrier collection. A promising efficiency of 11.57% has been achieved at 15% Ge alloying concentration with a significant enhancement in open-circuit voltage and fill factor. By further 10% Ag alloying to improve the absorber film morphology, a champion device with an efficiency of 12.25% has been achieved without an antireflective coating. This result emphasizes the feasibility of achieving homogeneous and controllable Ge alloying of kesterite semiconductors through the solution method, paving the way for further improvement and optimization of device performance.

THE OPTIMIZATION OF P3HT:PCBM THIN FILM THICKNESS FOR ORGANIC SOLAR CELLS

This study presents the complex relationship between film thickness and the properties of P3HT:PCBM thin films, looking at how different thicknesses affected their structural and optical properties. Poly(3, hexylthiophene) (P3HT) and poly(3, hexylthiophene) (PCMB) were blended in a 0.6:1 ratio and deposited using spin coating techniques. The research involve investigating the resulting changes in surface topography, optical properties, and electrical behaviour by systematically adjusting the film thickness through multiple coating repetitions ranging from one to three repetitions. Profilometric analysis revealed a direct relationship between film thickness and surface roughness, highlighting the importance of thickness in interfacial interactions within solar cells. Optical studies revealed fascinating trends in absorbance, transmittance, absorption coefficient, and extinction coefficient, highlighting the films' behaviour at various wavelengths. Surprisingly, regardless of thickness, the optical band gap remained constant, providing valuable insights for optimizing photon energy conversion. Measurements of the Hall effect revealed the effect of thickness on carrier mobility, concentration, conductivity, resistivity, and Hall voltage. Thinner films had higher mobility but lower carrier concentration, revealing a delicate balance critical for optimizing charge transport. The comprehensive analysis of the study sheds light on the complex interplay between film thickness and various properties, providing useful guidance for designing efficient P3HT:PCBM organic solar cells. This study's findings highlight the importance of precise control over film dimensions in improving the performance and efficiency of organic photovoltaic devices. This investigation paves the way for tailored approaches in the fabrication of next-generation organic solar cells, pushing the limits of renewable energy technology.

Dislocations in Crystalline Silicon Solar Cells

Dislocation is a common extended defect in crystalline silicon solar cells, which affects the recombination characteristics of solar cells by forming deep‐level defect states in the silicon bandgap, thereby reducing the lifetime of minority carrier. Hence, reducing the impact of defects on device performance is an effective strategy to optimize the performance of photovoltaic devices. This article reviews the observation and engineering of dislocation in Si solar cell. The structure and deformation of Si can be directly observed by chemical etching combined with electron microscopy. Also, more information about dislocation is obtained indirectly by monitoring the electrical and optical properties of Si. The classification, density, distribution of dislocations, and their interactions with other defects in Si can affect the lifetime of minority carriers and thereby reduce the performance of Si solar cells. In order to achieve higher cell efficiency, crystals with less or even no dislocation should be obtained. In addition to the specification of controlling the relevant parameters during the growth of silicon ingots to obtain the minimum dislocation density, it is necessary to study the behavior of dislocation in Si wafers under the combined action of external stress, temperature, and other defects.

Photoluminescence of bulk α -In2Se3 crystals irradiated by high-energy electrons

The photoluminescence (PL) spectra of bulk α-In2Se3 crystals before and after 10 MeV electrons irradiation with the 1015 and 1017 cm−2 fluences were studied in the temperature range from 7 to 340 K. Three main types of radiative recombinations corresponding to band-to-tail (BT), deep defects, and band-to-band (BB) recombination were manifested in the non-irradiated α-In2Se3 crystals. Also recombinations that can be associated with exciton recombinations at temperatures below 45 K are observed. After electron irradiation, noticeable changes in the PL spectra are observed. We detected a slight increase in activation energy of the BT recombination. An increase in the concentration of deep defects is also noted. The significant decrease in PL intensity of the BB recombinations indicates the formation of non-radiative recombination centers after electron irradiation with the 1017 cm−2 fluence. Our study may be useful for understanding the effects of high-energy electrons irradiation on the performance of electronic and photovoltaic devices based on α-In2Se3.

MXene-Enhanced Nanoscale Photoconduction in Perovskite Solar Cells Revealed by Conductive Atomic Force Microscopy.

The use of MXene materials in perovskite solar cells (PSCs) has received significant interest due to their distinct features that result from the termination of functional groups and the oxidation of MXene. Herein, we have used photoconductive atomic force microscopy (pcAFM) to map the local (nanoscale) photovoltaic performances of the Ti3C2Tx MXene nanosheet-integrated TiO2 (MXene@TiO2) electron transport layer-based PSCs to determine the influence of the treatment on the microscopic charge flow inside the devices. At different applied voltages, the morphology and current have been simultaneously measured with nanoscale resolution from the top surfaces of the solar cells without back contacts. The PSCs based on MXene@TiO2 exhibit more enhanced current flow across the grains than the only TiO2-based PSCs. At zero applied bias, the average local photocurrent for MXene-integrated PSCs is several times higher than the reference PSCs and decreases gradually when the positive bias is increased until the open circuit voltage. Considerable differences were also observed in the short circuit current among different locations that appear identical in AFM topography. Our findings reveal the potential of MXene-integrated ETLs to enhance the nanoscale photoconduction and inherent characteristics of the active layers, thereby improving the performance of the polycrystalline photovoltaic devices.

Efficiency of Emerging Photovoltaic Devices under Indoor Conditions

Emerging photovoltaic (PV) technologies are considered to be excellent candidates to be used as power sources for indoor and low‐light applications. The already demonstrated high power conversion efficiencies (PCEs) and the potential to manufacture perovskite, organic, or dye‐sensitized solar cells at low cost make them particularly interesting. In this work, the maximum PCE of PV devices under low‐light conditions is explored. The role of spectral mismatch, non‐radiative recombination, and parasitic Ohmic losses is investigated. The performed calculation provides guidelines to improve the low‐light performance of PV devices for ambient light. In addition, a simple measurement procedure for the indoor PCE is discussed.

Magnetic-biased chiral molecules enabling highly oriented photovoltaic perovskites

ABSTRACT The interaction between sites A, B and X with passivation molecules is restricted when the conventional passivation strategy is applied in perovskite (ABX3) photovoltaics. Fortunately, the revolving A-site presents an opportunity to strengthen this interaction by utilizing an external field. Herein, we propose a novel approach to achieving an ordered magnetic dipole moment, which is regulated by a magnetic field via the coupling effect between the chiral passivation molecule and the A-site (formamidine ion) in perovskites. This strategy can increase the molecular interaction energy by approximately four times and ensure a well-ordered molecular arrangement. The quality of the deposited perovskite film is significantly optimized with inhibited nonradiative recombination. It manages to reduce the open-circuit voltage loss of photovoltaic devices to 360 mV and increase the power conversion efficiency to 25.22%. This finding provides a new insight into the exploration of A-sites in perovskites and offers a novel route to improving the device performance of perovskite photovoltaics.

Electrodeposited polyaniline based carbon nanotubes fiber as efficient counter electrode in wire-shaped dye sensitized solar cells

Electrodeposited polyaniline over the carbon nanotubes fiber (CNTF) has been investigated as potential candidate to substitutes the Pt based auxiliary electrodes in unidimensional fibrous solar cells. CNTF, with excellent electrical and mechanical properties, modified with conducting polymer (polyaniline) via facile electrodeposition process which employed as cathodic materials showed efficient electrochemical reduction of triiodide ions in the fiber shaped dye-sensitized solar cells. Scanning electron microscopic analysis showed the efficacious integration of conducting polymer over the CNTF surface. The admirable electrocatalytic behavior of the fabricated electrode has investigated by electrochemical impedance spectroscopy and cyclic voltammetry. Current density and voltage (J–V) curves are used to quantify the photovoltaic performance of devices with different counter electrodes with fixed photoanode. With lower peak to peak separation, improved current density and better fill factor, exhibited the superior efficiency of modified electrode (PANI@CNTF). As compared to pristine fiber, polyaniline modification showed the outstanding performance with improved photovoltaics and electrochemical parameters measured by the J–V and CV curves, respectively.

Multifunctional Regioisomeric Passivation Strategy for Fabricating Self-Driving, High Detectivity All-Inorganic Perovskite Photodetectors.

The fluorination of the aromatic multifunctional Lewis base passivation strategy has been demonstrated recently as an effective approach to markedly enhance the performance of perovskite photovoltaic devices. However, the regulation mechanisms of the passivation efficiency by varying the functional group position of fluorine (F) in the regioisomers have received little attention and inadequate research. Herein, a pair of bifluorine-substituted aminobenzoic acid regioisomers [3-amino-2,6-difluorobenzoic acid (13-FABA) and 4-amino-3,5-difluorobenzoic acid (14-FABA)] were employed to investigate the passivation effects of Lewis bases dependent on behaviors of the ortho/meta-substituted position of fluorine. The density functional theory calculation on electron cloud density, interaction energy, and the basicity of Lewis bases combined with experimental evidence reveal that the ortho-effect induced by fluorine substitution weakens the passivating effect of 13-FABA Lewis base and induces its molecular propensity to form internal salts, accelerating the degradation and deterioration of the device performance. Conversely, 14-FABA with meta-connected fluorine atoms exhibit superior efficacy in suppressing defects and enhancing hydrophobicity. Eventually, the 14-FABA-modified photodetectors (PDs) achieved a high detectivity of 1.69 × 1013 Jones, the comparatively lower dark current density of 2.2 × 10-10 A/cm2 among all-inorganic perovskite PD systems. Our work has not only clarified the fundamental mechanisms of the F-substituted position effects of Lewis base on suppressing defects but also provided a promising passivation strategy for perovskite films via designing the regioisomeric atoms in a multifunctional Lewis base molecule.

Selective Interfacial Excited-State Carrier Dynamics and Efficient Charge Separation in Borophene-Based Heterostructures.

Borophene-based van der Waals heterostructures have demonstrated enormous potential in the realm of optoelectronic and photovoltaic devices, which has sparked a wide range of interest. However, a thorough understanding of the microscopic excited-state electronic dynamics at interfaces is lacking, which is essential for determining the macroscopic optoelectronic and photovoltaic performance of borophene-based devices. In this study, photoexcited carrier dynamics of β12 , χ3 , and α΄ borophene/MoS2 heterostructures are systematically studied based on time-domain nonadiabatic molecular dynamics simulations. Different Schottky contacts are found in borophene/semiconductor heterostructures. The interplay between Schottky barriers, electronic coupling, and the involvement of different phonon modes collectively contribute to the unique carrier dynamics in borophene-based heterostructures. The diverse borophene allotropes within the heterostructures exhibit distinct and selective carrier transfer behaviors on an ultrafast timescale: electrons tunnel into α΄ borophene with an ultrafast transfer rate (≈29fs) in α΄/MoS2 heterostructures, whereas β12 borophene only allows holes to migrate with a lifetime of 176fs. The feature enables efficient charge separation and offers promising avenues for applications in optoelectronic and photovoltaic devices. This study provides insight into the interfacial carrier dynamics in borophene-based heterostructures, which is helpful in further design of advanced 2D boron-based optoelectronic and photovoltaic devices.

Impact of Solid-State Charge Injection on Spectral Photoresponse of NiO/Ga2O3 p–n Heterojunction

Forward bias hole injection from 10-nm-thick p-type nickel oxide layers into 10-μm-thick n-type gallium oxide in a vertical NiO/Ga2O3 p–n heterojunction leads to enhancement of photoresponse of more than a factor of 2 when measured from this junction. While it takes only 600 s to obtain such a pronounced increase in photoresponse, it persists for hours, indicating the feasibility of photovoltaic device performance control. The effect is ascribed to a charge injection-induced increase in minority carrier (hole) diffusion length (resulting in improved collection of photogenerated non-equilibrium carriers) in n-type β-Ga2O3 epitaxial layers due to trapping of injected charge (holes) on deep meta-stable levels in the material and the subsequent blocking of non-equilibrium carrier recombination through these levels. Suppressed recombination leads to increased non-equilibrium carrier lifetime, in turn determining a longer diffusion length and being the root-cause of the effect of charge injection.

Extraction of Silica from Natural Deposits for the Production of Silicon in Photovoltaic Applications

The growing demand for renewable energy sources has driven extensive research and development in photovoltaic technologies. Silicon, in the form of single-crystalline or multi-crystalline wafers, dominates the photovoltaic industry due to its well-established fabrication processes and desirable electrical characteristics Silicon (Si) has long been recognized as the primary material in photovoltaic devices due to its excellent electrical properties and abundance. In this work, we provide a comprehensive review of the elaboration process of silicon for photovoltaic applications. We discuss the various techniques used to produce high-quality silicon, the main steps of the silicon elaboration process can be summarized as: Raw material preparation: Quartz sand, primarily composed of Silicon dioxide (SiO2), undergoes thorough treatment to eliminate undesired impurities. It is subjected to processes such as washing, crushing, and purification to obtain high-quality raw material. Silica reduction: The SiO2 raw material is then subjected to a high-temperature chemical reaction to reduce it into metallurgical silicon (Si). Various methods, including carbothermic reduction, are employed for this process. In carbothermic reduction, carbon, typically in the form of coke, acts as a reducing agent to react with the silica and produce pure silicon. Also the purification methods, and crystal growth techniques. Furthermore, we highlight the importance of silicon's material properties and their impact on photovoltaic device performance. The aim of work is to provide a deeper understanding of the elaboration of silicon we explore our chemical methods used to produce high-quality silicon, including the purification techniques and silicon precursor synthesis and its crucial role in the development of efficient and sustainable photovoltaic technologies.

TiCl4 precursor affecting the performance of HTM-free carbon-based perovskite solar cell

The presence of TiO2 used as an efficient electron transport layer is crucial to achieving high-performance solar cells, especially for a hole transport material (HTM)-free carbon-based perovskite solar cell (PSC). The hydrolysis of TiCl4 is one of the most widely used routes for forming TiO2 layer in solar cells, which includes the stock solution preparation from TiCl4 initial precursor and the thermal hydrolysis of the stock solution. The second thermal hydrolysis step has been extensively studied, while the initial hydrolysis reaction in the first step is not receiving sufficient attention, especially for its influence on the photovoltaic performance of HTM-free carbon-based devices. In this study, the role of TiCl4 stock solution in the growth process of TiO2 layer is examined. Based on the analysis of the Ti(IV) intermediate states for different TiCl4 concentrations from Raman spectra, 2 M TiCl4 precursor exhibits moderate nucleation and growth kinetics without generating too many intermediates which occurs in 3 M TiCl4 precursor, yielding ∼300 nm size spherical TiO2 agglomerates with a rutile phase. In the aspect of devices, the HTM-free carbon-based PSCs fabricated using 2 M TiCl4 precursor deliver a conversion efficiency beyond 17%, which may be attributed to the reduced defect in compact TiO2 layer.

Cesium Cyclopropane Acid‐Aided Crystal Growth Enables Efficient Inorganic Perovskite Solar Cells with a High Moisture Tolerance

AbstractWhile all‐inorganic halide perovskites (iHPs) are promising photovoltaic materials, the associated water sensitivity of iHPs calls for stringent humidity control to reach satisfactory photovoltaic efficiencies. Herein, we report a moisture‐insensitive perovskite formation route under ambient air for CsPbI2Br‐based iHPs via cesium cyclopropane acids (C3) as a compound introducer. With this approach, appreciably enhanced crystallization quality and moisture tolerance of CsPbI2Br are attained. The improvements are attributed to the modified evaporation enthalpy of the volatile side product of DMA‐acid initiated by Cs‐acids. As such, the water‐involving reaction is directed toward the DMA‐acids, leaving the target CsPbI2Br perovskites insensitive to ambient humidity. We highlight that by controlling the C3 concentration, the dependence of power conversion efficiency (PCE) in CsPbI2Br devices on the humidity level during perovskite film formation becomes favorably weakened, with the PCEs remaining relatively high (>15 %) associated with improved device stability for RH levels changed from 25 % to 65 %. The champion solar cells yield an impressive PCE exceeding 17 %, showing small degradations (<10 %) for 2000 hours of shell storage and 300 hours of 85/85 (temperature/humidity) tests. The demonstrated C3‐based strategy provides an enabler for improving the long‐sought moisture‐stability of iHPs toward high photovoltaic device performance.

Passive Photovoltaic Cooling: Advances Toward Low‐Temperature Operation

AbstractWith the great increase in installation, photovoltaics will develop as the main power supply source for the world shortly. However, the actual power generation and lifetime of photovoltaics are greatly compromised by the high working temperature under outdoor operation. In this review, the recent advances of four promising passive photovoltaic cooling methods are summarized with the aim to uncover their working principles, cooling performance, and application potential in photovoltaic devices. For radiative cooling, light management strategies with ultraviolet‐photon downshift and sub‐bandgap reflection are discussed in detail to reveal their great potential in reducing photovoltaic working temperature and enhancing power generation. Subsequently, the great cooling benefits of passive evaporative cooling are underlined in terms of its superior cooling power and temperature drop of photovoltaic devices. Moreover, the promising integrated cooling strategy is further highlighted due to its great potential in enhancing electricity production and fresh water supply. Most crucially, the remaining challenges and the authors'r insights are presented to advance the commercial applications of passive cooling methods in photovoltaics.

A Practical Approach Toward Highly Reproducible and High-Quality Perovskite Films Based on an Aging Treatment.

Solution processing of hybrid perovskite semiconductors is a highly promising approach for the fabrication of cost-effective electronic and optoelectronic devices. However, challenges with this approach lie in overcoming the controllability of the perovskite film morphology and the reproducibility of device efficiencies. Here, a facile and practical aging treatment (AT) strategy is reported to modulate the perovskite crystal growth to produce sufficiently high-quality perovskite thin films with improved homogeneity and full-coverage morphology. The resulting AT-films exhibit fewer defects, faster charge carrier transfer/extraction, and suppressed non-radiative recombination compared with reference. The AT-devices achieve a noticeable improvement in the reproducibility, operational stability, and photovoltaic performance of devices, with the average efficiency increased by 16%. It also demonstrates the feasibility and scalability of AT strategy in optimizing the film morphology and device performance for other perovskite components including MAPbI3 , (MAPbBr3 )15 (FAPbI3 )85 , and Cs0.05 (MAPbBr3 )0.17 (FAPbI3 )0.83 . This method opens an effective avenue to improve the quality of perovskite films and photovoltaic devices in a scalable and reproducible manner.