High Photovoltaic Performance Research Articles

Flexible Indoor Perovskite Solar Cells by In Situ Bottom-Up Crystallization Modulation and Interfacial Passivation.

A robust perovskite-buried interface is pivotal for achieving high-performance flexible indoor photovoltaics as it significantly influences charge transport and extraction efficiency. Herein, a molecular bridge strategy is introduced utilizing sodium 2-cyanoacetate (SZC) additive at the perovskite-buried interface to simultaneously achieve in situ passivation of interfacial defects and bottom-up crystallization modulation, resulting in high-performance flexible indoor photovoltaic applications. Supported by both theoretical calculations and experimental evidences, it illustrates how SZCs serve as molecular bridges, establishing robust bonds between SnO2 transport layer and perovskite, mitigating oxygen vacancy defects and under-coordinated Pb defects at interface during flexible fabrication. This, in turn, enhances interfacial energy level alignment and facilitates efficient carrier transport. Moreover, this in situ investigation of perovskite crystallization dynamics reveals bottom-up crystallization modulation, extending perovskite growth at the buried interface and influencing subsequent surface recrystallization. This results in larger crystalline grains and improved lattice strain of the perovskite during flexible fabrication. Finally, the optimized flexible solar cells achieve an impressive efficiency exceeding 41% at 1000 lux, with a fill factor as high as 84.32%. The concept of the molecular bridge represents a significant advancement in enhancing the performance of perovskite-based flexible indoor photovoltaics for the upcoming era of Internet of Things (IoT).

Effect of Position of Donor Units and Alkyl Groups on Dye-Sensitized Solar Cell Device Performance: Indoline-Aniline Donor-Based Visible Light Active Unsymmetrical Squaraine Dyes.

Indoline (In) and aniline (An) donor-based visible light active unsymmetrical squaraine (SQ) dyes were synthesized for dye-sensitized solar cells (DSSCs), where the position of An and In units was changed with respect to the anchoring group (carboxylic acid) to have In-SQ-An-CO2H and An-SQ-In-CO2H sensitizers, AS1-AS5. Linear or branched alkyl groups were functionalized with the N atom of either In or An units to control the aggregation of the dyes on TiO2. AS1-AS5 exhibit an isomeric π-framework where the squaric acid unit is placed in the middle, where AS2 and AS5 dyes possess the anchoring group connected with the An donor, and AS1, AS3, and AS4 dyes having the anchoring group connected with the In donor. Hence, the conjugation between the middle squaric acid acceptor unit and the anchoring -CO2H group is short for AS2, AS5, and AK2 and longer for AS1, AS3, and AS4 dyes. AS dyes showed absorption between 501 and 535 nm with extinction coefficients of 1.46-1.61 × 105 M-1 cm-1. Further, the isomeric π-framework of An-SQ-In-CO2H and In-SQ-An-CO2H exhibited by means of changing the position of In and An units a bathochromic shift in the absorption properties of AS2 and AS5 compared to the AS1, AS3, and AS4 dyes. The DSSC device fabricated with the dyes contains short acceptor-anchoring group distance (AS2 and AS5) showed high photovoltaic performances compared to the dyes having longer distance (AS1, AS3, and AS4) with the iodolyte (I-/I3-) electrolyte. DSSC device efficiencies of 5.49, 6.34, 6.16, and 5.57% have been achieved for AS1, AS2, AS3, and AS4 dyes, respectively; without chenodeoxycholic acid (CDCA), small changes have been observed in the device performance of the AS dyes with CDCA. Significant changes have been noted in the DSSC parameters (open-circuit voltage VOC, short-circuit current JSC, fill factor ff, and efficiency η) for the AS5 dye while sensitized with CDCA and showed highest DSSC efficiency of 8.01% in the AS dye series. This study revealed the potential of shorter SQ acceptor-anchoring group distance over the longer one and the importance of alkyl groups on the overall DSSC device performance for the unsymmetrical squaraine dyes.

Mediation of Interfacial Mo2C Bridging Effect in MoS2@Carbon Colloid Dots Featuring Improved Photovoltaic Performances of Si‐Based Hybrid Solar Cells

AbstractAdvances in silicon‐based hybrid solar cells with high photovoltaic performance, low synthetic cost, and sound environmental resistance are emerged as potential candidate for solar conversion. Solution‐processed few‐layer MoS2 sheets are regarded as compelling constitutes that paves ways for tailoring the solar harvesting capability; yet the improvement on charge separation of photoexcited carriers remains demanded, and the lack of environmental stability due to intentionally grabbing electrons from adsorbed moistures constrains the scope of practical assessment. In this work, the employment of MoS2/Mo2C/carbon colloid dots (CCDs) heterostructures within PEDOT:PSS matrix is invoked, where the transfer of photoexcited electrons from MoS2 is mediated with Mo2C electron‐transport channels, which further couple out the creation of positive trions by combining with defect‐bound excitons at CCD surfaces. These features dynamically involve with slow recombination probability and further improve the photovoltaic gain. Thus, the noticeable improvement of conversion efficiency of 16.1% with 1.6 times of efficiency enhancement outperforming the bare conventional hybrid solar cells is accomplished, and further exhibits a sound long‐term stability, which opens new avenues for exploiting the photophysical bound‐carrier transition on advanced photovoltaic applications.

CdS/CdSe/PbS quantum dots sensitized TiO2 eggshell hollow microspheres photoanode to boost photocurrent and power conversion efficiency of QDSSC

Light harvesting plays crucial role for high photovoltaic performance of quantum dots sensitized solar cell (QDSSC). However, there are still issues need to be tackled, such as enlarging light response range and enhancing light scattering capability. In this work, TiO2 eggshell hollow microspheres (EHMS) were synthesized by carbonaceous microspheres (CMS) template method and co-sensitized by CdS/CdSe/PbS quantum dots (QDs) for application in QDSSC. Compared with QDSSC based on TiO2 nanoparticles (NP) and TiO2 hollow microspheres (HMS), the TiO2 EHMS based QDSSC showed a remarkable increase of short-circuit current density (Jsc) to 24.81 mA cm−2 with a power conversion efficiency (PCE) of 4.07 %. Photoelectrochemical analysis of QDSSC indicate that CdS/CdSe/PbS QDs can enlarge the light response range, and the TiO2 EHMS improve the light scattering, leading to the improvement of light harvesting efficiency. Charges dynamics tests results proved that a larger charges recombination resistance at photoanode/electrolyte interface and longer electron lifetime can be achieved with TiO2 EHMS, contributing to the boost of Jsc. The presented study introduces a simple strategy for researchers interested in designing photoanode for various photoelectrochemical applications.

High photovoltaic performance of lead-free Cs2AgInCl6-xBrx perovskite solar cell using DFT and SCAPS-1D simulations

The search of the lead-free highly efficient photovoltaic material is a key challenge for next generation solar cells. The structural, electronic, and optical properties of lead-free double perovskite Cs2AgInCl6-xBrx (x= 0,1,2,3,4,5 and 6) were investigated using density functional theory and its photovoltaic performance by using one-dimensional solar cell capacitance simulator SCAPS-1D. By increasing Br content in Cs2AgInCl6, the lattice parameter increases and the electronic band gap decreases without affecting the direct nature of band gap at Г- point. By mixing Br in Cs2AgInCl6 also provides an effective way to tune the energy band gap. In addition, increasing the Br content in mixed halide composition Cs2AgInCl6-xBrx (x= 0,1,2,3,4,5 and 6) reproduces more dispersive conduction band minima and valence band maxima result in lower effective masses of both charge carriers and consequently higher bipolar carrier mobility. The optical properties of Cs2AgInCl6-xBrx, such as absorption coefficient, reflectivity, dielectric constants, refractive index, and extinction coefficient were investigated with different Br concentrations. Among all compositions, the Cs2AgInClBr5 exhibits better optical properties and behaves as poor reflector and good absorber in the visible region. The photovoltaic performance of different absorber layers of Cs2AgInCl6-xBrx compositions in the perovskites solar cell module with configuration FTO/ETL/Cs2AgInCl6-xBrx /HTL/Au is analysed by using the SCAPS-1D. It is also observed that Cs2AgInClBr5 has high bipolar carrier mobility, relatively higher stability and direct band gap value of 1.75 eV with the PCE of 21.95% in the visible region indicate the suitability of the Cs2AgInClBr5 as a promising lead-free photovoltaic material.

Investigating of novel inorganic cubic perovskites of A3BX3 (A=Ca, Sr, B[dbnd]P, As, X=I, Br) and their photovoltaic performance with efficiency over 28%

Inorganic halide perovskite-based compounds of A3BX3 have been gaining huge attention during the development of high-efficiency solar cells (SC) in recent years. This paper, investigating the physical and chemical properties could unveil its further potential to be used as absorber materials in advanced multijunction photovoltaics. The structural, optical, and electronic characterization of different compositional compounds of A3BX3 (A=Ca/Sr, BP/As, X=I/Br) perovskites are examined thoroughly to be used as absorber in high performance photovoltaics. The DFT study reveals direct bandgaps of 1.93 (2.60) eV, 1.58 (2.14) eV, 1.96 (2.63) eV, 1.58 (2.16) eV, 1.52 (2.30) eV, 1.26 (1.94) eV, 1.53 (2.32) eV, and 1.26 (1.96) eV at Γ for the Ca3AsBr3, Ca3AsI3, Ca3PBr3, Ca3PI3, Sr3AsBr3, Sr3AsI3, Sr3PBr3, and Sr3PI3 perovskites using PBE (HSE) methods with optical absorption of (2−5)x104 (a. u.) in the optical region (< 3.2 eV). Subsequently, the potential of the A3BX3 absorber has been investigated and analyzed at varying layer thickness, defect densities, and doping concentrations with SnS2 electron transport layer (ETL) layer using FTO/SnS2/A3BX3/Ni heterostructure with current density-voltage (J-V) characteristics and corresponding quantum efficiency (QE) observation. The power conversion efficiency (PCE) of 13.52, 20.88, 13.66, 22.47, 20.83, 28.16, 20.77, and 27.32% were achieved in Ca3AsBr3, Ca3AsI3, Ca3PBr3, Ca3PI3, Sr3AsBr3, Sr3AsI3, Sr3PBr3, and Sr3PI3 absorber-based heterojunction SC. Notably, the highest PV performance revealed a PCE over 28% with a VOC of 0.913 V, JSC of 35.75 mA/cm−3, and FF of 86.26% obtained in the Sr3AsI3 absorber SCs. Thus, these detailed studies on the physical and optoelectronic properties of eight (8) different possible absorber-based configurations including their PV applications unveil the huge potential of A3BX3 (i.e., Sr3AsI3) and provide resources for the practical cell development of inorganic perovskites-based high efficiency SC over 28%.

Polarization-Sensitive Self-Powered Schottky Photodetector with High Photovoltaic Performance Induced by Geometry-Asymmetric Contacts.

Polarization-sensitive photodetectors have attracted considerable attention owing to their potential application prospects in navigation, optical switching, and communication. However, it remains challenging to develop a facile and effective strategy to simultaneously meet the demands of low power consumption, high performance, and excellent polarization sensitivity. Herein, a series of low-symmetry two-dimensional (2D) ReSe2 Schottky photodetectors with geometry-asymmetric contacts are constructed. These devices exhibit excellent photoelectrical performance and impressive polarization sensitivity in the self-powered mode owing to the difference in the Schottky barrier height induced by the asymmetric contact areas, interfacial states, and thickness difference. Particularly, an outstanding responsivity of 379 mA/W, a decent specific detectivity of 6.8 × 1011 Jones, and a high light on/off ratio (Ilight/Idark) of over 105 under 635 nm light illumination are achieved. Scanning photocurrent mapping (SPCM) measurements further confirm that the ReSe2/drain overlapped region (corresponding to the smaller contact area side) with a higher Schottky barrier height plays a dominant role in the generation of photocurrent. Furthermore, the proposed device displays impressive polarization ratios (PRs) of 3.1 and 3.6 at zero bias under 635 and 808 nm irradiation, respectively. The high-resolution single-pixel imaging capability is also demonstrated. This work reveals the great potential of the ReSe2 Schottky photodetector with geometry-asymmetric contacts for high-performance, self-powered, and polarization-sensitive photodetection.

Strain Regulation of Mixed-Halide Perovskites Enables High-Performance Wide-Bandgap Photovoltaics.

Wide-bandgap mixed-halogen perovskite materials are widely used as top cells in tandem solar cells. However, serious open-circuit voltage (Voc ) loss restricts the power conversion efficiency (PCE) of wide-bandgap perovskite solar cells (PSCs). Herein, it is shown that the resulting methylammonium vacancies induce lattice distortion in methylammonium chloride-assisted perovskite film, resulting in an inhomogeneous halogen distribution and low Voc . Thus, a lattice strain regulation strategy is reported to fabricate high-performance wide-bandgap PSCs. Rubidium (Rb) cations are introduced to fill the A-site vacancy caused by the methylammonium volatilization, which alleviates shrinkage strain of the perovskite crystal. The reduced lattice distortion and increased halide ion migration barrier result in a homogeneous mixed-halide perovskite film. Due to improved carrier transport and suppressed nonradiative recombination, the Rb-treated wide-bandgap PSC (1.68eV) achieves an excellent PCE of 21.72%, accompanied by a high Voc of 1.22V. The resulting device maintains more than 90% of its initial PCE after 1500h under 1-sun illumination conditions.

Study on the photovoltaic characteristics of solar cells based on PbS quantum dots and carbon counter electrode

Lead sulfide (PbS) quantum dots (QDs) with their customizable and precise energy levels, have emerged as highly promising photosensitizers in quantum dots sensitized solar cells (QDSSCs). This research focuses on fabricating high-performance QDSSCs anchored on PbS QDs sensitized mesoporous titania coated FTO electrodes. The PbS QDs were grown on mesoporous TiO2 through the Successive Ionic Layer Absorption and Reaction (SILAR) method. The optical properties were analyzed using UV–visible absorption spectroscopy, revealing that the SILAR cycles impacted the size and band gap of the PbS QDs. By analyzing the absorption data and the hyperbolic band model (HBM), the size of the PbS QDs were estimated to be 1.65 nm, 2.126 nm, 2.326 nm, 2.5692 nm, and 3.048 nm for 1 to 5 SILAR cycles, respectively. The effect of SILAR cycles was investigated, demonstrating a direct correlation between the number of SILAR cycles and the photovoltaic performance of the device. The maximum power conversion efficiency of 2.07 % was attained using 2 SILAR cycles, in contrast to 1.33 % and 1.63 % obtained with one and three SILAR cycles, respectively. Furthermore, impedance spectroscopy (IS), (Cs-V) (Rs-V) was employed at different frequencies, highlighting lowest series resistance for 2 SILAR cycles confirming its highest photovoltaic performance. Moreover, The utilization of a low-cost polysulfide electrolyte and carbon electrode has yielded superior or comparable outcomes compared to previously reported data.

High-performance radial junction solar cells on ZnO coated stainless steel with excellent flexibility and durability

High flexibility and industrial compatibility are the key factors for developing large-scale lightweight, wearable, and portable thin film flexible solar cells. Here, a rather flexible and mechanically durable three-dimensional (3D) radial junction (RJ) solar cell has been directly constructed over discrete standing Si nanowires (SiNWs), upon flexible ZnO-coated stainless steel (SS) foil substrates. The ZnO layer deposited on the SS surface can optimize the density of SiNWs to improve the optoelectronic performance. A power conversion efficiency of 6.01% has been accomplished, with open-circuit voltage and photo-current density of 0.76 V and 12.87 mA/cm2, respectively. Remarkably, the outstanding mechanical stability of these RJ devices has been recorded, which can sustain > 4000 cycles of large bending to a radius of 2.5 mm, with only a 7% efficiency decrease. Note that the one-pump-down fabrication procedure of this 3D nanostructure RJ cells upon flexible ZnO-coated SS substrates is compatible with the industrial-mainstream Roll-to-Roll technology, holding thus a strong promise to establishing a simple and low-cost strategy for high-performance and durable flexible photovoltaics.

Molecular Interactions Regulation by Adding a Third Component with High Miscibility Suppresses the Energetic Disorder and Reduces Energy Loss for Efficient Ternary Solar Cells

In the advancement of organic solar cells (OSCs), the ternary strategy has emerged as an effective approach for fabricating devices with high photovoltaic performance. In this contribution, we have introduced...

One-step dual-additive passivated wide-bandgap perovskites to realize 44.72%-efficient indoor photovoltaics

A one-step dual-additive strategy enables high-quality wide-bandgap perovskite films with efficient defect passivation, resulting in a certified record PCE of 44.72%, with a high Voc of 1.069 V, and an FF of 82.3% under U30 light.

Femtosecond laser annealing of fluorine-doped tin oxide films towards high-performance perovskite photovoltaics

Femtosecond laser annealing preparation of a superhydrophilic FTO surface helps promote the photoelectric conversion efficiency of perovskite solar cells to 22.33%.

Efficient organic solar cells based on low-cost pentacyclic fused-ring small molecule acceptors with a fill factor over 80%

Small molecule acceptor (SMA) materials with pentacyclic fused-ring backbone are considered as promising candidates for balancing the low-cost and high photovoltaic performance for commercialization of organic solar cells (OSCs). However,...

A novel heterojunction layer-assisted interfacial defect control strategy for high-performance solar cells

The energy level matching of perovskites was regarded as the prerequisite for achieving high photovoltaic performance.

Novel and high photovoltaic performance sensitizers of copolymeric sulfur coordination metal complexes of benzimidazolyl benzodithiophene derivatives

Compared to the complexes using N and O as coordination atoms, whose PCE has never exceeded 10%, the sensitizers using the softer S as a coordination atom have made a breakthrough in their performance, with a PCE of 10.96%.

Achieving High External Quantum Efficiency for ITIC‐Based Organic Solar Cells with Negligible Homo Energy Offsets

AbstractMinimizing energy loss in organic solar cells (OSCS) is critical for attaining high photovoltaic performance. Among the parameters that correlated to photovoltaic performance, the energy offsets between donor–acceptor pairs play a vital role in photoelectric conversion processes. For so far reported a large number of non‐fullerene acceptors (NFAs), only Y6 and its derivatives can achieve external quantum efficiencies (EQEs) over 80% with negligible energy offsets when combined with polymeric donors. Thus, understanding the relationship between energy offsets and energy losses in representative NFAs is the key to further enhancing the efficiency of OSCs. In this study, a series of wide‐bandgap polymer donors based on pyrrolo[3,4‐f]benzotriazole‐5,7(6H)‐dione (TzBI) and benzo[1,2‐c:4,5‐c′] dithiophene‐4,8‐dione building blocks are combined with representative NFAs, including ITIC and Y6, to gain deep insights into their photovoltaic performances and related energy losses. Outstanding EQEs (≈70%) and suppressed non‐radiative recombination are achieved at negligible energy offsets. Moreover, it is noted that a prolonged exciton lifetime of acceptor is not essential to obtain high EQEs in OSCs with negligible energy offsets. Eventually, ITIC derivatives with high electroluminescence efficiencies and near‐infrared absorptions have the potential to be assembled to obtain high‐efficiency OSCs.

Novel approach towards optically active and hexagonal plate morphology of Zinc doped Perylene Tetra Carboxylic Di Anhydride composite for high photovoltaic and flexible supercapacitor performances

This paper reports novel features like photo-voltaic and energy storage capacity as dual performance in Zinc-Perylene Tetra-Carboxylic Di-Anhydride (Zn-PTCDA) composite have synthesized via hydrothermal method. This follows escape-by-crafty mechanism chemical reaction that produces the orthorhombic crystal structure. The Morphology transformation from stacked pyramids of PTCDA into hexagonal plates and rod structures of Zn-PTCDA. The optical study suggest that Zn-PTCDA composite provide compelling evidence for the Dye sensitized solar cell (DSSC) with Power Conversion Efficiency (PCE) is lower 0.2 % due to charge carrier recombination and promote to utilize this as transport layer of any solar cell. The electrochemical performance of pure Zn-PTCDA exhibits capacitance retention of 44.2 % while Zn-PTCDA-Graphene Oxide (Zn-PTCDA-GO) has capacitance retention 84.5 % over 5000 Galvanostatic-Charging and Discharging (GCD) cycles. The best specific capacitance 561 F/g at 2 A/g along with discharge through light emitting diode (LED) illumination for 2–3 min and also excellent energy density 31.5 Whr/kg and power density 4.5 kW/kg values. The incorporation of Zinc into PTCDA dye demonstrates Metal Organic Frameworks can provide improvements in the performances of both supercapacitors and dye-sensitized solar cells. The integration of both can instant storage of converted energy is needed solution to solve energy demand in future.

Highly Crystalized Cl-Doped SnO2 Nanocrystals for Stable Aqueous Dispersion Toward High-Performance Perovskite Photovoltaics.

Tin dioxide (SnO2 ) with high conductivity and low photocatalytic activity has been reported as one of the best candidates for highly efficient electron transport layer (ETL) in perovskite solar cell (PSC). The state-of-the-art SnO2 layer is achieved by chemical bath deposition with tunable properties, while the commercial SnO2 nanocrystals (NCs) with low tunability still face the necessity of further improvement. Here, a kind of highly crystallized Cl-doped SnO2 NCs is reported that can form very stable aqueous dispersion with shelf life up to one year without any stabilizer, which can facilitate the fabrication of PSCs with satisfactory performance. Compared to the commercial SnO2 NCs regardless of the extrinsic Cl-doping conditions, the intrinsic Cl-doped SnO2 NCs effectively suppress the energy barrier and reduces the trap state density at the buried interface between perovskite and ETL. Consequently, stable PSCs based on such Cl-doped SnO2 NCs achieve a champion efficiency up to ≈25% for small cell (0.085 cm2 ) and ≈20% for mini-module (12.125 cm2 ), indicating its potential as a promising candidate for ETL in high-performance perovskite photovoltaics.

How backreflection contributes to light absorption for high-performance radial junction photovoltaics

A robust radial junction (RJ) structure directly constructed upon the surface of a flexible Al foil substrate shows a promising potential to boost wearable and portable applications, where the silicon nanowire (SiNW) supported multilayer has proven beneficial in excellent mechanical stability and sufficient light harvesting. Assigned to the beneficial backreflection contributed by the Al foil, a much larger light current can be achieved than that on glass. While a comprehensive understanding of the light absorption under the backreflection of the substrate remains mainly unexplored. Herein, a straightforward comparison of light absorption of RJ units on Al and glass substrates, within a theoretical framework based on a finite-element simulation, is performed. Then, taking SiNW geometric parameters and i-layer thickness into account, the evolutions of light harvesting and the external quantum efficiency curves are systematically studied. These results indicate that, under the backreflection of the substrate, the light absorption shows a reduced dependency on SiNW geometry and i-layer thickness to some extent, laying a critical basis to establish a simpler/easier fabrication process for high-performance flexible RJ thin film photovoltaics.