Efficiency Improvement Of Solar Cells Research Articles

Revealing composition and structure dependent deep-level defect in antimony trisulfide photovoltaics

Antimony trisulfide (Sb2S3) is a kind of emerging light-harvesting material with excellent stability and abundant elemental storage. Due to the quasi-one-dimensional symmetry, theoretical investigations have pointed out that there exist complicated defect properties. However, there is no experimental verification on the defect property. Here, we conduct optical deep-level transient spectroscopy to investigate defect properties in Sb2S3 and show that there are maximum three kinds of deep-level defects observed, depending on the composition of Sb2S3. We also find that the Sb-interstitial (Sbi) defect does not show critical influence on the carrier lifetime, indicating the high tolerance of the one-dimensional crystal structure where the space of (Sb4S6)n ribbons is able to accommodate impurities to certain extent. This study provides basic understanding on the defect properties of quasi-one-dimensional materials and a guidance for the efficiency improvement of Sb2S3 solar cells.

Optimization of photoelectrode by structural engineering for efficiency improvement of dye-sensitized solar cells at different light intensity

Abstract Titanium (Ti) is a promising choice as the photoelectrode substrate of dye-sensitized solar cells (DSSCs) due to its high compatibility and stability. To enhance the efficacy of Ti more than a substrate, structural modification of Ti via anodization is performed to construct a TiO2 nanotube structure on the surface. Optimization of the TiO2 nanotube structure as a function of anodization potential is carried out in conjunction with the photovoltaic characterization of DSSCs using commercial N719 dye and synthesized organic D-Dye as the sensitizer. The highly oriented TiO2 nanotube structure not only increases the interactive contact area in between the Ti substrate and active semiconductor layer composed of TiO2 nanoparticles but also serves as a fast pathway for charge transfer and an additional channel to carry sensitizers, thereby greatly improving the cell efficiency. Maximum efficiency of 7.67% (Jsc of 16.06 mA/cm2, Voc of 0.693 V, and FF of 0.689) is achieved for the cell constructed by anodized Ti photoelectrode using N719 dye under 1 sun illumination. Incorporation of D-Dye further enhances the cell efficiency to 7.93% (Jsc of 16.65 mA/cm2, Voc of 0.701 V, and FF of 0.68) and this is attributed to the spatial effect of D-Dye molecules which have a long wingspan capable of suppressing the molecular aggregation. Under low light illuminations, maximum efficiency of 15.31% and 18.06% are reached for the cells constructed by anodized Ti photoelectrode using D-Dye under 3000 and 6000 lx illumination, respectively.

Improvement of CIGS solar cell efficiency with graded bandgap absorber layer

There are several ways to increase the efficiency of a solar cell. In addition to increasing efficiency, the important subject is to build the cell at a lower cost and try to reduce the heat losses of the cell. In this article, research was conducted on CIGS solar cell in which some methods were proposed that in addition to reducing the losses of a CIGS solar cell, we could achieve maximum efficiency with the minimum thickness of the absorber layer. To simulate and perform mathematical calculations, the Atlas software of Silvaco was used in this research. It should be noted that in all proposed structures, the thickness of the layer is minimized, and also the absorber layer is p-type. In the first stage, the structure of a ZnO:Al/Zn0.83Mg0.17O/CdS/Graded CIGS/MO was simulated in which the thickness of the graded CIGS (absorber layer) is 1 µm. Graded CIGS is a structure in which the bandgap of material CuIn1−xGaxSe2 changes linearly from x1 to x2. In this study, the x variation is from 0.7 to 0.1, so that the decrease in x corresponds to the decrease in band gap linearly from 1.45 to 1.07 eV. In this stage, the cell efficiency was 17.1%. In the second stage, the buffer layer was upgraded to increase the cell efficiency, that is, instead of CdS layer with the bandgap of 2.4 eV, ZnO0.5S0.5 with the bandgap of 2.8 eV was used that made the efficiency to become 19.0%. In the third stage, an electron reflector layer was added to the structure of the first stage; indeed at this stage, the effect of the electron reflector layer on the solar cell of the first stage was displayed. In the fourth stage (last stage), CGS (CGS is CuGaSe2) layer was used as the electron reflector layer, which caused the cell efficiency to reach 28.3%.

Pathways for efficiency improvements of industrial PERC silicon solar cells

The global manufacturing capacity of Passivated Emitter and Rear Cell (PERC) devices on p-type Czochralski-grown silicon (Cz-Si) wafers is increasing rapidly. This paper analyses various industrial process improvements carried out in our lab to improve the efficiency of large-area Cz-Si PERC solar cells from 20.7% to 21.9%. The key improvements presented in this paper include the transition from line to dot-shaped laser openings in the rear dielectric stack, a dual printing approach for the front fingers and implementation of a laser-doped selective-emitter structure. A nanosecond (ns) pulsed laser source with 532 nm wavelength was used for both the rear dielectric ablation and the front laser doping. By adopting a systematic power loss analysis approach and targeting the largest power loss mechanisms at various stages of development, the best efficiency of the solar cells in this experimental study was improved from 20.7% to 21.9%. Pathways for further improvements in efficiency are analysed, including the application of passivated-contact structures in a PERC-like cell.

Design of double‐layer SiN x :H film and its application in c‐Si PERC solar cells

The existing solar cell anti-reflection film technology still cannot adequately meet the light trapping needs of solar cells. In this Letter, double-layered SiN x :H films were prepared for c-Si solar cells by plasma enhanced chemical vapor deposition (PECVD). Herein, the authors introduce a simple, convenient method to lower the reflectance in silicon solar cells by applying double-layered SiN x :H film to increase the refractive index of such film. Compared to the single layer film devices, the reflectance of the double-layered SiN x :H film can be significantly reduced by >30% through enhanced absorption of light in solar cells. This method has achieved an average of 0.08% conversion efficiency, with the highest being 0.18%. In addition, the double-layer film solar cells also showed a better passivation performance than that of the single-layer film, so that the minority carrier lifetime was up to 137 µs. Therefore, the improvement of solar cell efficiency mainly come from the decrease of reflectivity and the improvement in film passivation performance. The work of this Letter demonstrated the light trapping advantages and passivation enhancement performance of double-layer films applied to single crystal silicon solar cells.

Formation of Intermediate SiO2 nano-Layer As Effective Passivation at Si/TiO2 Interface By Zone Heating Recrystallization Toward Perovskite/Silicon Tandem Solar Cell

A monolithic perovskite/c-Si tandem solar cell has attracted a lot of attention in the field of photovoltaic for its high theoretical energy conversion efficiency and cost-effectiveness. For this technology to reach its potential, optimization and compromised for both perovskite top cell and silicon bottom cell has to be investigated.In a single-junction perovskite solar cell, the hybrid organic-inorganic perovskite light-absorbing layer is sandwiched with electron and hole transporting layers (ETL and HTL). For optimal carrier extraction, the bandgap of the transporting layers has to match the perovskite material such that electron can be selectively transported to the ETL while only hole moves through HTL. In the majority of perovskite solar cells, titanium dioxide (TiO2) is used as ETL, for its high bandgap alignment, ease of fabrication, and low cost. For this reason, a tandem solar cell with c-Si/ETL(TiO2)/Perovskite/HTL structure has the potential to be highly efficient and low in cost [1].In a single-junction c-Si solar cell, surface passivation of silicon using large bandgap materials such as Al2O3, SiO2 or SiNx is widely known to reduce the velocity of carrier recombination and thus increase the carrier lifetime at silicon surface. This approach, however, is not applicable in tandem solar cells with c-Si/ETL/Perovskite/HTL structure, as the utilization of large bandgap materials in between c-Si and ETL causes bandgap misalignment and prevents interlayer exchange of carriers between perovskite and silicon cells. For this reason, a new approach that accommodates both interlayer exchange of carriers and passivate silicon surface effectively is required.In most of Si-Oxides (Al2O3, TiO2, ZnO, etc.) interface, the existence of SiOx layer is unavoidable and widely known due to high reactivity of silicon surface under oxidizing atmosphere [2]. Furthermore, while the improvement of perovskite solar cell efficiency by controlling spray pyrolysis of TiO2 and the thermal annealing procedure has been reported [3], prolonged exposure to heat during TiO2 fabrication might negatively affect the performance of silicon bottom cell, and thus requires further studies. Due to the high surface passivation effect of thermally grown SiO2 layer, we hypothesized that a proper crystallization of SiOx layer might be able to increase the lifetime of carrier at Si/TiO2 interface and mitigate the surface passivation problem in tandem solar cells with c-Si/ETL/Perovskite/HTL structure.Zone Heating Recrystallization (ZHR) is a process developed by our research group in which the surface of samples was selectively heated by the scanning of highly focus line lamp heater with elliptical mirror. Previously, we reported the utilization of ZHR to obtain smooth seed layers for thin-film silicon solar cell applications [4, 5] among other functionalities. The use of high-intensity lamp heater in ZHR process combines with high transparency of TiO2 layer makes ZHR a suitable process to selectively treat the Si/TiO2 interface and test our hypothesis on SiOx crystallization.With the introduction of ZHR, the minority carrier lifetime of Si/TiO2 interface was increased from less than 5 µs to more than 250 µs. Different scanning rates of lamp heater in ZHR process lead to different carrier lifetime, with higher scanning rates lead to higher carrier lifetime. To explain this phenomenon, cross-sectional TEM images of Si/TiO2 treated with different scanning rate was taken and analyzed. Here, we found that samples treated with higher scanning rates of ZHR have thinner SiOx layer and higher carrier lifetime. The relationship between SiOx thickness and carrier lifetime might be explained with the interface trap density of SiOx layer in which thinner layer shows lower interface trap density. This leads to lower carrier recombination velocity and therefore higher carrier lifetime at Si/TiO2 interface.References Mailoa J. P. et al., A 2-terminal perovskite/silicon multijunction solar cell enabled by a silicon tunnel junction. Appl. Phys. Lett. 106, 121105 (2015).Black L. E. et al., Explorative studies of novel silicon surface passivation materials: Considerations and lessons learned. Solar Energy Materials and Solar Cells 188, 182- 189 (2018).Nukunudompanich M., Ihara M. et al., Dominant effect of the grain size of the MAPbI3 perovskite controlled by the surface roughness of TiO2 on the performance of perovskite solar cell. CrysEngComm 22, 2718-2727 (2020).Ihara M. et al., Fabrication of silicon thin films with defects below detection limit of electron spin resonance for solar cells by high-speed zone-melting crystallization of amorphous silicon. Appl. Phys. Lett. 79, 3809 (2001).Lukianov A., Ihara M. et al., Formation of the seed layers for layer-transfer process silicon solar cells by zone-heating recrystallization of porous silicon structures. Appl. Phys. Lett. 108, 213904 (2016). Figure 1

Improvement in solar cell efficiency based on the MAPbI3 films extracted by a mixed anti-solvent

In this report, we discuss the 22% efficiency improvement of solar cells based on the MAPbI3 perovskite film extracted with a mixed anti-solvent. The film quality of MAPbI3 extracted from the mixed anti-solvent of ether and isopropanol is improved greatly. The average grain size of the film may be enlarged twice. We argue that some solvents residing in the precursor may effectively promote the crystallization process of MAPbI3 to form large grains. We believe that this study may open a method to fabricate high-quality MAPbI3 perovskite films for highly efficient solar cells.

How Oxygen Exposure Improves the Back Contact and Performance of Antimony Selenide Solar Cells.

The improvement of antimony selenide solar cells by short-term air exposure is explained using complementary cell and material studies. We demonstrate that exposure to air yields a relative efficiency improvement of n-type Sb2Se3 solar cells of ca. 10% by oxidation of the back surface and a reduction in the back contact barrier height (measured by J-V-T) from 320 to 280 meV. X-ray photoelectron spectroscopy (XPS) measurements of the back surface reveal that during 5 days in air, Sb2O3 content at the sample surface increased by 27%, leaving a more Se-rich Sb2Se3 film along with a 4% increase in elemental Se. Conversely, exposure to 5 days of vacuum resulted in a loss of Se from the Sb2Se3 film, which increased the back contact barrier height to 370 meV. Inclusion of a thermally evaporated thin film of Sb2O3 and Se at the back of the Sb2Se3 absorber achieved a peak solar cell efficiency of 5.87%. These results demonstrate the importance of a Se-rich back surface for high-efficiency devices and the positive effects of an ultrathin antimony oxide layer. This study reveals a possible role of back contact etching in exposing a beneficial back surface and provides a route to increasing device efficiency.

Synthesis of boron-doped CQDs and its use as an additive in P3HT:PCBM layer for efficiency improvement of organic solar cell

This study reports the synthesis of boron-doped CQDs (B-CQDs) and the using as a novel additive for organic solar cells. we introduced B-CQDs P3HT:PCBM bulk heterojunction organic solar cells (OSCs). The structural and morphological characterization results showed that the optical absorption and film crystallinity can be easily enhanced by B-CQDs additive in P3HT:PCBM solution. Additionally, with the improved crystallinity of P3HT, the effective interchain interaction and phase separation in photoactive layer were achieved. As a result, ~50% improving of FF of the device with 5 vol% of B-CQDs additive was determined. Thanks to improved photovoltaic characteristics, best performing device showed a power conversion efficiency of 2.7% (with ~50% improvement). This report shows that the addition of optimized vol% of B-CQDs into the photoactive blend strongly improves the absorption and leads to achieve efficient charge separation and transport in OSCs.

Achievable efficiency improvement of Sb2Se3 thin-film solar cells through interface engineering

Antimony selenide (Sb2Se3) is a promising light-absorbing material for the thin-film solar cells (TFSCs). However, the low efficiency output of the Sb2Se3-based TFSC is still one of the largest obstacles to restrain its development. In this work, tin oxide (SnO2) nanoparticle film is used as the electron transport layer (ETL) for the Sb2Se3-based TFSC. To further enhance the device performance, spin coated CdCl2 films are employed to modify the SnO2 ETL. As a result, preferable orientation with an increased intensity of (221) peak and a reduced intensity of (120) peak in the XRD patterns are observed for the Sb2Se3 film, which enhances the carrier transport within the Sb2Se3 absorber. Meanwhile, the CdCl2 suppresses the carrier recombination at the interface between the Sb2Se3 and SnO2. Therefore, the optimized device shows an improved power conversion efficiency from 2.02% to 4.03%, and also exhibits a strong stability in ambient air.

Simulation, Analysis, and Characterization of Calcium-Doped ZnO Nanostructures for Dye-Sensitized Solar Cells

In this research article, the authors have discussed the simulation, analysis, and characterization of calcium-doped zinc oxide (Ca-doped-ZnO) nanostructures for advanced generation solar cells. A comparative study has been performed to envisage the effect of Ca-doped ZnO nanoparticles (NP), seeded Ca-doped ZnO nanorods (NR), and unseeded Ca-doped ZnO NR as photoanodes in dye-sensitized solar cells. Simulations were performed in MATLAB fuzzy logic controller to study the effect of various structures on the overall solar cell efficiency. The simulation results show an error of less than 1% in between the simulated and calculated values. This work shows that the diameter of the seeded Ca-doped ZnO NR is greater than that of the unseeded Ca-doped ZnO NR. The incorporation of Ca in the ZnO nanostructure is confirmed using XRD graphs and an EDX spectrum. The optical band gap of the seeded substrate is 3.18 eV, which is higher compared to those of unseeded Ca-doped ZnO NR and Ca-doped ZnO NP, which are 3.16 eV and 3.13 ev, respectively. The increase in optical band gap results in the improvement of the overall solar cell efficiency of the seeded Ca-doped ZnO NR to 1.55%. The incorporation of a seed layer with Ca-doped ZnO NR increases the fill factor and the overall efficiency of dye-sensitized solar cells (DSSC).

Impurity mechanism of monocrystalline silicon PERC solar cells stimulated by prelight-induced degradation

Although the monocrystalline silicon (mono-Si)-passivated emitter and rear contact (PERC) solar cells have achieved incredible efficiency, they still can be further improved by hydrogenation. So the hydrogenation was performed to investigate the improvement of large area (>240 cm2) mono-Si PERC solar cells and estimate the significance of previous light-induced degradation (pre-LID) under a high-intensity infrared (HI-IR) LEDs source platform. Then, the results indicated that the parameters, such as open-circuit voltage (Uoc) and short-circuit current density (Jsc) and fill factor (FF), could be better improved after LED hydrogenation with the execution of the pre-LID. The efficiency of mono-Si PERC solar cells with pre-LID increased by ~0.190 ± 0.005%abs. for 2 min, which was higher than that without pre-LID (0.115 ± 0.005%abs.). Moreover, the results showed that the efficiency of large area mono-Si PERC solar cells with light-induced degradation (LID) treatment after LED hydrogenation only existed a slight degradation of about −0.253 ± 0.005%rel.. Compared with mono-Si PERC solar cells without pre-LID, the efficiency improvement and LID mitigation of mono-Si solar cells with pre-LID was faster and more significant by LED hydrogenation, so that the LED hydrogenation time significantly can shorten from 6 to 2 min. Additionally, the possible presence of a boron-oxygen (BO) model was estimated, and this BO model is susceptible to be activated by the injection of external energy, resulting in more BO defects in the process of pre-LID, so that subsequent hydrogenation rate becomes faster.

Na-doping-induced modification of the Cu2ZnSn(S,Se)4/CdS heterojunction towards efficient solar cells

Na-doping-induced modification of the Cu 2 ZnSn(S,Se) 4 /CdS heterojunction enables photovoltaic device with a remarkable conversion efficiency. The physical reasons for the improvement of V OC and J SC are analyzed by theoretical and experimental studies. • Na-doping can induce the heterojunction modification of Cu 2 ZnSn(S,Se) 4 /CdS • Optical losses in CdS are mitigate as its thinner thickness by Na doping treatment. • Proper Na-doping treatment enables device with a remarkable conversion efficiency. • Physical reasons are analyzed by theoretical and experimental studies. • This work provides a deeper understanding of Na doped CZTSSe thin film solar cells. It is very important to understand why a small amount of alkali metal doping in Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells can improve the conversion efficiency. In this work, Na-doped CZTSSe is prepared by a simple solution method, and then the effects on the surface properties of the absorber layer, the buffer layer growth, and the modifications of the solar cell performance induced by the Na doping are studied. The surface of the absorber layer is more Cu-depletion and less roughness due to the Na doping. In addition, the contact angle of the surface increases because of Na doping. As a consequence, the thickness of the CdS buffer layer is significantly reduced and the optical losses in the CdS buffer layer are decreased. The difference of quasi-Fermi levels ( E Fn – E Fp ) increases with a small amount of Na doping in the CZTSSe solar cell, so that open circuit voltage ( V OC ) increased significantly. This work offers new insights into the effects of Na doping on CZTSSe via a solution-based approach and provides a deeper understanding of the origin of the efficiency improvement of Na-doped CZTSSe thin film solar cells.

Efficiency improvement of the heterojunction solar cell using an antireflection Hf-doped In2O3 thin film prepared via glancing angle magnetron sputtering technology

Abstract The needle-like antireflection Hf-doped In2O3 thin films (IHFO) were prepared at a substrate temperature of 200 °C by glancing angle radio frequency magnetron sputtering technology. The structural, electrical and optical properties of the needle-like IHFO thin films were characterized. The significant reduction of reflection loss of the conventional and needle-like IHFO bilayer films deposited on the textured silicon was observed. The short-circuit current and efficiency of the solar cell were improved by 0.52 mA/cm2 and 0.39% utilizing a needle-like IHFO thin film as an antireflection layer.

Extraction Current Transients for Selective Charge-Carrier Mobility Determination in Non-Fullerene and Ternary Bulk Heterojunction Organic Solar Cells

The field of organic solar cells has recently gained broad research interest due to the introduction of non-fullerene small-molecule acceptors. The rapid improvement in solar cell efficiency put in...

Efficiency improvement of indoor organic solar cell by optimization of the doping level of the hole extraction layer

Currently, the use of self- and low-powered, small dimension electronic devices for indoor use, such as smart meters, sensors, actuators, and wearable devices, is increasing our standard of living via the Internet of Things technology. Normal power sources are not recommended for these devices because of their small scale; however, an efficient means of powering them is via ambient energy harvesters. Indoor photovoltaic (IPV) cells are a very good power source option due to the ease of accessibility and availability of indoor light. Furthermore, IPV cells based on organic materials are one of the best options due to their good spectral matching and mechanical flexibility. Despite tremendous effort being devoted to the improvement of efficiency, applicability, longevity, and commercial acceptability of organic IPV devices, further research is needed to achieve their integrated use. In an organic IPV cell, the hole extraction layer (HEL) is an important component used to improve the hole extraction ability of the device. An alternative p-type semiconducting material that is cheaper, more environmentally stable, more processable, less sensitive to humidity, and highly conductive, is highly recommended. Therefore, in this work, we have attempted to develop a highly efficient organic IPV cell by optimizing the doping concentration of its HEL. We have used water-stable polyaniline (PANI) (doped with poly (sodium-4-styrenesulfonate) (PSS)) as the HEL because of its good environmental stability, low acidity, low price, and insensitivity to humidity. It has been observed that the indoor light energy harvesting ability of the device is strongly dependent on the doping concentration of its HEL and at an optimized concentration of PSS (100 mg), under the illumination of a 500 lx LED lamp; the device exhibits a power conversion efficiency value of 8.1%.

The effect of a two-dimensional structure on the dielectric constant and photovoltaic characteristics

Along with the recent intensive studies on improvements in organic solar cell efficiency, a new material design concept of organic semiconductors has become important for the practical realization of solar cells. Donor materials with a high dielectric constant that markedly boost the efficiency have been proposed, but theoretical material designs and/or experimental results are still scarce. In this paper, we report on a combined theoretical and experimental result of donors with high dielectric constants. Our design guidelines were to bind a conventional one-dimensional thiophene-based donor molecule in a two-dimensional (2D) manner, which would lead to extended π-conjugation and a large dielectric constant. Impedance spectroscopy measurements showed that the relative dielectric constant increased unilaterally with extending the 2D structure. Organic solar cells based on these materials in the combination of [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) show that an increase in power-conversion efficiency was observed experimentally with increasing the extension of the molecular structure. These sults imply that this is a potentially promising design strategy for the 2D extension of the molecules, and it eventually leads to a high dielectric constant and to an efficient power conversion of the organic solar cell material.

Analysis and improvement of CIGS solar cell efficiency using multiple absorber substances simultaneously

In this paper, the efficiency of a CIGS solar cell was increased in several stages. The common structure and configuration of the CIGS solar cell are the ZnO:Al/ZnO/CdS/CIGS/MO combination whose efficiency is optimized approximately 20% for CIGS with thickness of 2 µm and 17% for CIGS with thickness of 1 µm. In this article, thickness of CIGS is 1 µm and the efficiency of this type of solar cell was calculated using Atlas software of Silvaco. In the first step, by applying Zn1−xMgxO material with x = 0.17 instead of ZnO material, the cell efficiency was 20.7% and then by adding GaAs as the electron reflector layer, we were able to achieve 27.1% efficiency and at the end, to increase the efficiency, one absorber layer is added under the CIGS absorber. This absorber layer is CIS (CIS is CuInSe2) that made the efficiency to become 27.9%. Indeed, CIGS absorber layer is not able to absorb all photons of the sun. So, this added absorber layer is able to absorb a part of low-energy photons, which lead to increasing the efficiency of the solar cell. It should be noted that in the whole process of this article, CIGS and CIS absorber layers are p-type.

Absorption enhancement and efficiency improvement of an organic solar cell embedded with core–shell Au@ITO nanoparticles

In this paper, we propose a new design of plasmonic organic solar cells (OSCs). It consists of a protective layer of SiO2, an anti-reflective glass of ITO, a compact buffer of PEDOT:PSS, an absorbing organic material of P3HT:PCBM, and a reflective layer of Al. A square periodic array of core–shell nanoparticles (Au@ITO NPs) is embedded in the active layer of P3HT:PCBM in order to enhance the absorption of OSC. Although ITO coating slightly reduces efficiency, it prevents the oxidation of gold NPs and increases the OSC lifetime. We study the effect of numerous parameters such as the core radius, shell thickness, and core material on the optical absorption by solving Maxwell’s equations using the three-dimensional finite-difference time-domain method. The drift–diffusion and Poisson’s equations are solved with an in-house software tool by discretizing the solar cell using the finite element method. To the best of our knowledge, this paper is the first to apply the real model of trap-assisted recombination and Auger recombination of used materials to the simulations to match them with the experimental results. The numerical results show the proposed OSC embedded with Au@ITO NPs has the built-in potential of 2.9 V, short-circuit current of 16.63 mA/cm2, the open-circuit voltage of 1.14 V, maximum power of 17.25 mW/cm2, fill-factor of 0.91, the conduction band of 2.8 eV, electron quasi-Fermi level of 2.35 eV, hole quasi-Fermi level of 0.6 eV and an efficiency of 17.25%. Furthermore, the performance of the proposed OSC has an improvement of 25% compared to conventional OSCs.

Drastic improvement in dye-sensitized solar cell efficiency by electrosorption based dye staining of titania semiconductor photoanode

Herein, we report dye-sensitized solar cells (DSSCs) made of dye stained TiO2 semiconductor photoanode fabricated using a quick and novel electrosorption assisted dye-staining process. Electrosorption, through the application of electrochemical potential, can manipulate the interaction of target compounds (in this case “dye”) with an electrode surface. To demonstrate the importance of the electrosorption assisted dye-staining process, two commercially available metal-based dyes (N719 and Z907) and two metal-free dyes (D2d = (Z)-2-cyano-3-(4-((E)-2-(6-(4-methoxyphenyl)-9-octyl-9H-carbazol-3-yl)vinyl)phenyl)acrylic acid and T-SB-C = (E)-2-cyano-3-(4-((E)-4-(diphenylamino)styryl)phenyl)acrylic acid) having carboxylic acid type anchoring group were chosen. By this process, the dye loading realized on the photoanodes was more than that of the conventional soaking process. In case of N719 dye, dye loading was enhanced about 100% from 0.58 x10−7 to 1.21 x10−7 mol cm−2, and power conversion efficiency (PCE) by 35%. The electrosorption assisted dye-staining process discussed in this study requires only an hour to fabricate photoanode versus 12–48 h required for the conventional soaking process.