High Power Conversion Efficiency Research Articles

Heterostructures stacked with X2SY (X = In, Ga; Y = Se, Te) and g-C2N monolayers for high power conversion efficiency solar cells: insight from electronic properties and nonadiabatic dynamics

A g-C2N/In2STe heterostructure with high power conversion efficiency (10.01%) and carrier utilization efficiency was screened from 114 different configurations based on its electronic properties and nonadiabatic molecular dynamics.

The effect of rigid-block length in elastomer-containing photoactive block copolymers on the photovoltaic and mechanical properties of polymer solar cells

The development of elastomer-containing photoactive block copolymers with regulated rigid-block lengths results in organic solar cells with high power conversion efficiency (17.3%) and mechanical robustness (toughness = 1.8 MJ m−3).

Alkaline-earth metal embedded expanded phthalocyanine nanosheets with direct band gaps and high power conversion efficiency

A new class of alkaline earth metals embedded expanded phthalocyanine nanosheets with high stabilities, direct band gaps, high absorption coefficients and power conversion efficiencies were uncovered. These materials have promising potential applications in nanoelectronics and optoelectronics.

Recent progress and prospects of dimer and multimer acceptors for efficient and stable polymer solar cells.

High power conversion efficiency (PCE) and long-term stability are essential prerequisites for the commercialization of polymer solar cells (PSCs). Small-molecule acceptors (SMAs) are core materials that have led to recent, rapid increases in the PCEs of the PSCs. However, a critical limitation of the resulting PSCs is their poor long-term stability. Blend morphology degradation from rapid diffusion of SMAs with low glass transition temperatures (Tgs) is considered the main cause of the poor long-term stability of the PSCs. The recent emergence of oligomerized SMAs (OSMAs), composed of two or more repeating SMA units (i.e., dimerized and trimerized SMAs), has shown great promise in overcoming these challenges. This innovation in material design has enabled OSMA-based PSCs to reach impressive PCEs near 19% and exceptional long-term stability. In this review, we summarize the evolution of OSMAs, including their research background and recent progress in molecular design. In particular, we discuss the mechanisms for high PCE and stability of OSMA-based PSCs and suggest useful design guidelines for high-performance OSMAs. Furthermore, we reflect on the existing hurdles and future directions for OSMA materials towards achieving commercially viable PSCs with high PCEs and operational stabilities.

Efficient and stable semitransparent perovskite photovoltaics via a Lewis base incorporation.

Semitransparent perovskite solar cells (ST-PSCs) have great potential in building integrated photovoltaics. However, semitransparent devices suffer from a low electron mobility and an imbalanced charge-carrier transport, leading to an unsatisfactory power conversion efficiency (PCE) and limited stability. Herein, we report a high-performance ST-PSC via the incorporation of a special Lewis base. A better perovskite with an improved crystallinity and less defects was achieved, and a matched energy level alignment between the perovskite and [6,6]-phenyl-C61-butyric acid methyl ester was also induced, thereby leading to a high electron mobility and an exceptional balance of hole and electron mobility approaching 1 : 1. The prepared ST-PSC exhibited a PCE of 20.22% at average visible transmittance (AVT) of 4.93%, 18.32% at AVT of 14.38%, and 15.00% at AVT of 25.65%. These PCEs are the highest values among those ST-PSCs based on top metallic electrodes at a close AVT. The ST-PSCs maintained 92% of the initial PCE in storage for 1000 h, and they held 84% of the initial PCE under the continuous maximum power point tracking measurement for 530 hours. The work paves the way to realize ST-PSCs with a high PCE, high light utilization efficiency and substantially enhanced stability.

Metal oxide-embedded carbon-based materials for polymer solar cells and X-ray detectors.

This study examines the effects of hybrid nanoparticles made of NiO@rGO (reduced graphene oxide) and NiO@CNT (carbon nanotubes) on PCDTBT and PCBM active layers in glass/ITO/HTL/active-layer/LiF/Al structured bulk heterojunction (BHJ) polymer solar cells (PSCs) and X-ray photodetectors. These hybrid nanoparticles were used to create BHJ solar cells and photodetectors, and microscopic research was conducted to determine how they affect the structure of the devices. The findings show that compared to conventional matrices, the active layers with NiO@rGO and NiO@CNT incorporation have increased the charge carrier capacities and exciton dissociation properties. In order to assess their impact on the characteristics of charge transport, various weight ratios of these hybrid nanoparticles dispersed in polymer junctions are being investigated. Notably, compared to the pure PCDTBT:PCBM active layer (power conversion efficiency (PCE) = 4.35%), the NiO@CNT device has the highest PCE = 6.42% which, among the tested configurations, demonstrates its superior performance in converting sunlight into electricity. Among the tested X-ray detector materials, "NiO@CNT" achieves the best performance with a sensitivity of 1.92 mA Gy-1 cm-2. Through improved interfacial behaviors and effective charge transport, this work highlights the potential of these cutting-edge hybrid nanoparticles to enhance the performance of organic electronic devices.

Study of the microscopic mechanism of stepwise charge injection in co-sensitive DSSCs in the framework of a D-π-A dye and chlorophyll.

The newly synthesized dye molecules TY6 and CXC22 were selected to explain the influence of anthracene and acetylene groups on the power conversion efficiency (PCE) of the molecules at the microscopic level. Theoretical simulation was carried out to understand the properties of the two molecules, including frontier molecular orbitals, absorption spectra, light absorption efficiency, intramolecular charge transfer (ICT), dye regeneration, I-V prediction, etc. The results suggest that for CXC22, adding an anthracene and acetylene group in the conjugate bridge greatly enhances the molecule's absorption wavelength and molar extinction coefficient; CXC22 also has significant advantages in the intramolecular charge transfer and comparatively better dye regeneration and electron injection. These parameters cause CXC22 to have a higher PCE. Subsequently, CXC22 and the chlorophyll molecule (CHL7) were selected for co-sensitization to regulate performance. The stable structure in the co-sensitization configuration was screened, and the absorption spectrum characteristics and charge transfer mechanisms were revealed for the co-sensitization system. The designed evaluation model predicted that the PCE of CO1 (the cosensitive system of CXC22 and TY6 in H-H configuration is referred to as CO1) could reach 16.78%. This work provides an idea for developing an efficient dye-sensitized solar cell system.

Dimensional diversity (0D, 1D, 2D, and 3D) in perovskite solar cells: exploring the potential of mixed-dimensional integrations

This review article includes dimensional diversity and exploring the potential of mixed-dimensional integrations to improve the stability and performance of PV devices.

Improved Dual Active Bridge DC–DC Converter With Symmetric Bipolar Output by Utilizing a Switched-Capacitor Circuit for Bipolar DC Distribution System

The bipolar dc distribution system is a promising solution due to its advantages in efficiency and reliability, but there are also challenges of pole voltage imbalance. By using a simple switched-capacitor circuit, this paper presents a semi-dual active bridge converter with symmetrical bipolar output characteristics. The converter is capable of single-stage power conversion, offering the advantages of low cost and high-power conversion efficiency. Moreover, the symmetrical bipolar output voltage can be achieved without an additional voltage balancer and feedback control under unbalanced load conditions, which reduces system cost and control system complexity. In addition, the proposed converter also has a significant advantage over existing solutions in terms of the number of semiconductor devices and magnetic components. A detailed analysis of the proposed converter is presented, including the operation principle, steady-state performance, soft-switching performance, voltage gain, voltage/current stresses, efficiency and loss analysis, and control method. Finally, a 1-kW prototype is developed and tested to verify the performance of the proposed converter.

In-Situ Crosslinked Matrix enables Efficient and Mechanically Robust Organic Solar Cells with Frozen Nano-Morphology and Superior Deformability

Flexible organic solar cells (F-OSCs) with excellent mechanical robustness and high performance are in high demand for their applications in wearable devices. However, considering their high-power conversion efficiency, achieving mechanical...

A Brief Study of the Carbon Counter Electrode for Photosensor based on DSSC

We investigate the fabrication of photosensor devices based on dye sensitized solar cells (DSSC). DSSC photovoltaic cells use solar light energy to trigger chemical reactions as a source of electrical energy. DSSC has several advantages, namely low production costs, environmental friendliness, easy fabrication, and high-power conversion efficiency. Therefore, DSSC is ideal for use as a photosensor. Most DSSCs use a wet electrolyte to provide ionic conductivity to the photoanode. However, long-term use of liquid electrolyte causes corrosion which can reduce the stability of the resulting current. In this research, yttria stabilized zirconia (YSZ) solid electrolyte was used to prevent corrosion of the photoanode. Samples were characterized using XRD, SEM, UV-Vis and photoresponse. The XRD results show the crystallinity of nanoporous TiO2 and YSZ. SEM results show that the average particle size distribution of TiO2 /YSZ DSSC cells is 315 nm. The sensitivity, rise and fall times of the photosensor have been calculated by varying the counter electrode when testing the photoresponse. Finally, Graphene as a counter showed higher voltage and current compared to AC which is 0.2 V and 0.05 µA.

High-Efficiency Partial Power Converter for Integration of Second-Life Battery Energy Storage Systems in DC Microgrids

High-Efficiency Partial Power Converter for Integration of Second-Life Battery Energy Storage Systems in DC Microgrids

Enhancing perovskite solar cell performance through PbI2 in situ passivation using a one-step process: experimental insights and simulations.

The in situ passivation of a methylammonium lead triiodide (MAPbI3) phase spin-coated via a one-step process was experimentally investigated to elucidate their fundamental properties. Structural analysis revealed that MAPbI3 adopts a tetragonal crystal structure with a small excess of PbI2 (0.03 M) segregating at grain boundaries. Optical characterization indicated a band gap of 1.53 eV, highlighting the material's potential as an effective visible light absorber. To facilitate the fabrication of efficient perovskite solar cells (PSCs), we employed a primary n-i-p planar structure (ITO/SnO2/MAPbI3/spiro-OMeTAD/Au) in drift-diffusion SCAPS-1D simulations using experimental data from MAPbI3 layers containing excess PbI2. The simulations predicted a high power conversion efficiency (PCE) of approximately 24%. We further analyzed the impact of series resistance, shunt resistance, MAPbI3 thickness, defect density, as well as radiative and Auger recombination on photovoltaic performance, aiming to identify optimal parameters for enhanced device efficiency. Additionally, the use of ohmic contacts with AZO and IZO as the front and rear contacts, respectively, in the optimized device structure (AZO/SnO2/MAPbI3/spiro-OMeTAD/IZO) resulted in a PCE of 26.03%. These findings provide valuable insights for future research aimed at achieving high-efficiency bifacial MAPbI3 perovskite solar cells.

Photo-accelerated oxidation of spiro-OMeTAD for efficient carbon-based perovskite solar cells

Photo-accelerated oxidization enables fast production of a Spiro-OMeTAD hole transport layer in perovskite solar cells. This strategy delivers high power conversion efficiency and overcomes barriers to mass manufacturing.

Surface passivation with an electron-donating sulfonate group for high-performance and stable perovskite solar cells

A new passivator, 4-aminophenyl sulfone (APS), containing a Lewis base group (SO), could interact with the uncoordinated Pb2+ on perovskite surface, which not only reduces trap state density but also induces a more p-type surface of perovskite film.

Improved photovoltaic performance and stability of perovskite solar cells by adoption of an n-type zwitterionic cathode interlayer.

Recently, inverted perovskite solar cells (PeSCs) have witnessed significant advancements; however, their long-term stability remains a challenge because of the oxidation of silver cathodes to form AgI by mobile iodides. To overcome this problem, we propose the integration of an electron-deficient naphthalene diimide-based zwitterion (NDI-ZI) as the cathode interlayer. Compared to the physical ion-blocking layer, it effectively captures ions by forming ionic bonds via electrostatic Coulombic interaction to suppress the migration of iodide and Ag ions. The NDI-ZI interlayer also suppresses the shunt paths and modulates the work function of the Ag electrode by forming interface dipoles, thereby enhancing charge extraction. FA0.85Cs0.15PbI3 based PeSCs incorporating NDI-ZI exhibited a noticeably high power conversion efficiency of up to 23.3% and outstanding stability, maintaining ∼80% of their initial performance over 1500 h at 85 °C and over 500 h under continuous 1-sun illumination. This study highlights the potential of a zwitterionic cathode interlayer in diverse perovskite optoelectronic devices, leading to their improved efficiency and stability.

Improving crystallization and photoelectric performance of CsPbI<sub>2</sub>Br perovskite under ambient air via dynamic hot-air assisted recrystallization strategy

CsPbI<sub>2</sub>Br thin films prepared in ambient air are susceptible to humidity, resulting in low coverage, poor crystallization quality, numerous pinholes, and easy transformation into non perovskite phases. To overcome the troubles of pervoksite fabrication in ambient air, a feasible way is to reduce the moisture around the films as much as possible according to dynamic hot-air assisted strategy. However, the hot air accelerates the evaporation rate of solvent, resulting in the decrease of grain size. In order to improve the crystal growth and long-term stability in dynamic hot-air assisted strategy, in this work, we present a dynamic hot-air assisted recrystallization (DHR) strategy to prepare high-quality CsPbI<sub>2</sub>Br thin films in ambient air (i.e. the CsPbI<sub>2</sub>Br thin films prepared via dynamic hot-air strategy are recrystallized by using a green solvent (methylamine acetate) with high viscosity coefficient). Under ambient air with high humidity (RH＞60%), the CsPbI<sub>2</sub>Br thin film with high coverage, (100) preferred orientation, large average grain size, and stable structure is prepared via DHR strategy. The dynamic hot-air process can effectively reduce the moisture around the film and increase the nucleation sites in the precursor solution, thereby improving the coverage of the film. However, this process inevitably results in the significant decrease of grain size (<i>R</i><sub>ave</sub>= 0.32 μm) (i.e. more grain boundaries), exacerbating non-radiative recombination of carriers associated with trap states at these boundaries. The high coverage increases the grain-to-grain contact area, facilitating complete recrystallization. Thus, the recrystallization process can significantly increase the grain size (<i>R</i><sub>ave</sub> = 2.63 μm) and obtain a (100) preferred orientation (<i>I</i><sub>(110)</sub>/<i>I</i><sub>(200)</sub> = 0.006), resulting in high photoluminescence intensity and long fluorescence lifetime (118 ns). The unencapsulated CsPbI<sub>2</sub>Br perovskite solar cell (PSC) optimized via DHR strategy with low hysterescence factor (2.34%) and high repeatability exhibits a high power conversion efficiency (PCE = 17.55%), which is higher than those of most CsPbI<sub>2</sub>Br PSCs prepared in ambient air and gloveboxes previously reported. Moreover, the unencapsulated CsPbI<sub>2</sub>Br PSC possesses an excellent storage stability under ambient air with high humidity (RH > 60%), remaining 96% of the original PCE after aging 40 days. This provides a promising approach for achieving high-performance and long-term stable CsPbI<sub>2</sub>Br films under ambient air with high humidity, which is expected to promote the commercialization process of perovskite/silicon tandem cells and semi-transparent devices.

High-efficiency ITO-free organic solar cells through top illumination

Our polymer solar cells boast an extraordinary power-to-weight ratio of 31.07 W g−1. Such devices demonstrate robust photostability, retaining 93% of their initial power conversion efficiency even after 48 hours of continuous light exposure.

Thiophene-based Solar Cell. A Review

Abstract: In recent years, perovskite solar cells, which use a hybrid inorganic-organic material, have also made remarkable progress and achieved a rapid increase in efficiency. The organic materials used are usually small conductive molecules, polymers or oligomers. The fused thiophenes, polythiophenes and olithiophenes used for this purpose are presented. The condensed thiophene-based small molecule for DSSCs shows important properties such as simplicity of synthesis and purification methods, well-defined and reproducible structures, but low power conversion efficiencies. Polymers of thiophene for DSSCs show high power conversion efficiencies, especially in ternary systems, even >19%; however, they have poor long-term stability because of the molecular size and packing properties of the polymer chains. Oligomers of thiophene for DSSCs have good long-term stability but low power conversion efficiencies.

Suppressing surface and interface recombination to afford efficient and stable inverted perovskite solar cells.

The top surface of the perovskite layer and the interface with the electron transporting layer play a key role in influencing the performance and operational stability of inverted perovskite solar cells (PSCs). A deficient or ineffective surface passivation strategy at the perovskite/electron transport layer interface can significantly impact the efficiency and scalability of PSCs. This study introduces phenyl dimethylammonium iodide (PDMAI2) as a passivation ligand that exhibits improved chemical and field-effect passivation at the perovskite/C60 interface. It was found that PDMAI2 not only passivates surface defects and suppresses recombination through robust coordination but also repels minority carriers and reduces contact-induced interface recombination. The approach leads to a twofold reduction in defect densities and photoluminescence quantum yield loss. This approach enabled high power conversion efficiencies (PCEs) of 25.3% for small-area (0.1 cm2) and 23.8% for large-area (1 cm2) inverted PSCs. Additionally, PDMAI2 passivation enabled PSCs to demonstrate steady operation at 65 °C for >1200 hours in an ambient environment.