Improved Performance and Stability of Organic Solar Cells by the Incorporation of a Block Copolymer Interfacial Layer

In a proof-of-concept study, this work demonstrates that incorporating a specifically designed block copolymer as an interfacial layer between a charge transport layer and the photoactive layer in organic solar cells can enhance the interface between these layers leading to both performance and stability improvements of the device. This is achieved by incorporating a P3HT50-b-PSSx block copolymer as an interfacial layer between the hole transporting and photoactive layers, which results in the improvement of the interfacial roughness, energy level alignment, and stability between these layers. Specifically, the incorporation of a 10 nm P3HT50-b-PSS16 and a 13 nm P3HT50-b-PSS23 interfacial layer results in a 9% and a 12% increase in device efficiency respectively compared to the reference devices. In addition to having a higher initial efficiency, the devices with the block copolymer continue to have a higher normalized efficiency than the control devices after 2200 h of storage, demonstrating that the block copolymer not only improves device efficiency, but crucially, prevents degradation by stabilizing the interface between the hole transporting layer and the photoactive layer. This study proves that appropriately designed and optimized block copolymers can simultaneously stabilize and improve the efficiency of organic solar cells

Design and Device Numerical Analysis of Lead-Free Cs₂AgBiBr₆ Double Perovskite Solar Cell

The advancement of lead-free double perovskite materials has drawn great interest thanks to their reduced toxicity, and superior stability. In this regard, Cs2AgBiBr6 perovskites have appeared as prospective materials for photovoltaic (PV) applications. In this work, we present design and numerical simulations, using SCAPS-1D device simulator, of Cs2AgBiBr6-based double perovskite solar cell (PSC). The initial calibrated cell is based on an experimental study in which the Cs2AgBiBr6 layer has the lowest bandgap (Eg = 1.64 eV) using hydrogenation treatment reported to date. The initial cell (whose structure is ITO/SnO2/Cs2AgBiBr6/Spiro-OMeTAD/Au) achieved a record efficiency of 6.58%. The various parameters that significantly affect cell performance are determined and thoroughly analyzed. It was found that the conduction band offset between the electron transport layer (ETL) and the Cs2AgBiBr6 layer is the most critical factor that affects the power conversion efficiency (PCE), in addition to the thickness of the absorber film. Upon engineering these important technological parameters, by proposing a double ETL SnO2/ZnO1-xSx structure with tuned absorber thickness, the PCE can be boosted to 14.23%

Current spray-coating approaches to manufacture perovskite solar cells

The research interest in perovskite solar cells (PSCs) is increasing because of the rapid developments in the recent times. PSCs exhibit exceptional photovoltaic performance, which is presently more than 25% for single-junction solar cells; thus, they have a high potential of achieving industrial commercialization and production. Nevertheless, the greatest issue faced by commercial applications is the device area of a PSC. Several fabrication techniques have been presented to create large-area PSCs such as slot-die coating, spray coating, blade coating and vacuum deposition. This paper reviews the spray coating method for the development of PSC. Developments in spray-cast PSCs that have occurred in the last few years are summarized in the study, with the focus on the deposition method, performance, morphology, stability, and large-area fabrication. It concludes that spray coating is the most suitable method for achieving the scalable manufacturing of large-area PSCs with moderate to high efficiencies

TCAD Device Simulation of All-Polymer Solar Cells for Indoor Applications: Potential for Tandem vs. Single Junction Cells

The utilization of indoor photovoltaics makes it feasible to harvest energy from artificial light sources. Although single-junction indoor photovoltaics have demonstrated exceptional efficacy when using LED lighting, there is still a need for more comprehensive testing of tandem structures. Herein, the first systematic TCAD simulation study on the potential for tandem all-polymer solar cells (all-PSCs) for indoor applications is provided. The presented all-PSCs are based on experimental work in which the top wide bandgap subcell comprises a polymer blend PM7:PIDT, while the bottom narrow bandgap subcell has a polymer blend PM6:PY-IT. Standalone and tandem cells are simulated under AM1.5G solar radiation, and the simulation results are compared with measurements to calibrate the physical models and material parameters revealing PCE values of 10.11%, 16.50%, and 17.58% for the front, rear, and tandem cells, respectively. Next, we assessed the performance characteristics of the three cells under a white LED environment for different color temperatures and light intensities. The results showed a superior performance of the front cell, while a deterioration in the performance was observed for the tandem cell, reflecting in a lower PCE of 16.22% at a color temperature of 2900 K. Thus, an optimized tandem for outdoor applications was not suitable for indoor conditions. In order to alleviate this issue, we propose designing the tandem for indoor lightening by an appropriate choice of thicknesses of the top and bottom absorber layers in order to achieve the current matching point. Reducing the top absorber thickness while slightly increasing the bottom thickness resulted in a higher PCE of 27.80% at 2900 K

Improving the structural, optical, and electrical properties of carboxymethyl cellulose/starch/selenium oxide nanocomposites for flexible electronic devices

Abstract Nanocomposites based on biopolymers are interesting materials owing to their multifunctionality and ease of preparation. In this study, the solution casting method was used to mix selenium oxide nanoparticles (SeO2 NP) made by a solvothermal method into a bio-blend of carboxymethyl cellulose and starch (CMC/St). XRD analysis showed that SeO2 NP increased the amorphous portion inside the blend. HR-TEM revealed the spherical morphology of these NP with an average diameter of 16.88 nm. The FE-SEM indicated a satisfactory uniform distribution and homogeneity in the surface morphology of the films. FTIR confirmed the interaction between SeO2 and the blend functional groups. The films preserved good transmission after doping, and their direct and indirect band gaps decreased. The refractive index, absorption index, optical conductivity, and other dispersion parameters were improved after SeO2 loading. The DC conductivity of the blend is in the range of 3.8 × 10−7 to 5.6 × 10−4 S/m and improved after loading SeO2 NP. The IV characteristic curves in the temperature range of 300–415 K were studied to figure out the conduction mechanism in the CMC/St/SeO2 composites. Because the optical and electrical properties improved, these nanocomposites could be used for coatings and other things like waveguides, photovoltaic cells, and light-emitting diodes

MPPT of PEM Fuel Cell Using PI-PD Controller Based on Golden Jackal Optimization Algorithm

Subversive environmental impacts and limited amounts of conventional forms of energy necessitate the utilization of renewable energies (REs). Unfortunately, REs such as solar and wind energies are intermittent, so they should be stored in other forms to be used during their absence. One of the finest storage techniques for REs is based on hydrogen generation via an electrolyzer during abundance, then electricity generation by fuel cell (FC) during their absence. With reference to the advantages of the proton exchange membrane fuel cell (PEM-FC), this is preferred over other kinds of FCs. The output power of the PEM-FC is not constant, since it depends on hydrogen pressure, cell temperature, and electric load. Therefore, a maximum power point tracking (MPPT) system should be utilized with PEM-FC. The techniques previously utilized have some disadvantages, such as slowness of response and largeness of each oscillation, overshoot and undershoot, so this article addresses an innovative MPPT for PEM-FC using a consecutive controller made up of proportional-integral (PI) and proportional-derivative (PD) controllers whose gains are tuned via the golden jackal optimization algorithm (GJOA). Simulation results when applying the GJOA-PI-PD controller for MPPT of PEM-FC reveal its advantages over other approaches according to quickness of response, smallness of oscillations, and tininess of overshoot and undershoot. The overshoot resulting using the GJOA-PI-PD controller for MPPT of PEM-FC is smaller than that of perturb and observe, GJOA-PID, and GJOA-FOPID controllers by 98.26%, 86.30%, and 89.07%, respectively. Additionally, the fitness function resulting when using the GJOA-PI-PD controller for MPPT of PEM-FC is smaller than that of the aforementioned approaches by 93.95%, 87.17%, and 87.97%, respectively

Model Development of a Hybrid Battery–Piezoelectric Fiber System Based on a New Control Method

By increasing the application of smart wearables, their electrical energy supply has drawn great attention in the past decade. Sources such as the human body and its motion can produce electrical power as renewable energy using piezoelectric yarns. During the last decade, the development of the piezoelectric fibers used in smart clothes has increased for energy-harvesting applications. Therefore, the energy harvesting from piezoelectric yarns and saving process is an important subject. For this purpose, a new control system was developed based on the combination of the sliding mode and particle swarm optimization (PSO). Using this method, due to the piezoelectric yarn cyclic deformation process, electrical power is produced. This power is considered the input voltage to the controlling system modeled in this article. This system supplies constant voltage to be saved in a battery. The battery supplies power for the electrical elements of smart fabric structure for different applications, such as health care. It is shown that the presence of PSO led to the improvement of system response and error reduction by more than 30%

Autonominen videokuvan siirtoon soveltuva tietoverkkoratkaisu viranomaisajoneuvoihin

Työn tavoitteena oli luoda tutkielma, jossa huomioidaan olosuhteita ja tilanteita, joita voi tulla eteen videokuvan siirrossa kenttäolosuhteissa. Kenttäolosuhteissa toimittaessa on yhteyksien toimivuusvarmuuteen kiinnitettävä erityistä huomiota. Toimivista tietoliikenneyhteyksistä saattaa olla kiinni ihmishenkien tai materiaalien pelastuminen. Insinöörityössä tutkittiin eri kuvansiirtotapoja viranomaisajoneuvojen välillä. Työssä tutkittiin neljää erilaista tiedonsiirtotapaa, kahta kaapelitoteutusta ja kahta langatonta versiota. Tutkimus oli luonteeltaan teoreettinen, lukuun ottamatta WLAN mittauksia. Työssä pohditaan pääsääntöisesti erinäisiä ratkaisuja ja toteutustapoja. Langattoman lähiverkon (WLAN) toimivuus kenttäolosuhteissa on sidoksissa moneen käyttäjästä riippumattomaan asiaan kuten säähän, rakenteisiin ja maaston muotoihin. Tästä syystä langatonta lähiverkkoa ei voida pitää ensisijaisena tiedonsiirtomuotona. Tätä asiaa tukivat myös suoritetut mittaukset. WLAN:ia voidaan kuitenkin käyttää muodostettaessa verkko ajoneuvon lähietäisyydelle esimerkiksi kameraa tai tietokonetta varten. Työssä tutkittiin kotimaisen Ajeco Oy:n 4Com -monikanavareitittimen ominaisuuksia ja todettiin sen soveltuvan hyvin viranomaisajoneuvon kuvansiirron runkolaitteeksi. Johtopäätöksenä voidaan todeta, että kaapeliyhteydet ovat tiedonsiirto-ominaisuuksiltaan varmempia kuin langattomat vaihtoehdot. Kaapeliyhteyksien käyttökuntoon saattaminen on kuitenkin hitaampaa. Mahdollisissa jatkotutkimuksissa olisi huomioitava pidemmän matkan langattomien tiedonsiirtotapojen, kuten esimerkiksi WIMAXin, käyttömahdollisuuksia.This thesis aims to describe the effects of field operations on video transmission. Under field conditions, the functionality of data communications requires special attention. Problems in data connections may lead to material losses and in the worst case prevent saving human lives. The thesis examines different methods of transferring image between two vehicles. In detail, four different data transmission methods are compared; two cable implementations and two wireless versions. Problems and challenges are approached from a theoretical aspect. Specific implementation solutions are compared and their strengths and weaknesses are demonstrated. There are numerous different aspects that affect wireless LAN (WLAN) performance in field conditions. These aspects include the weather, infrastructure and terrain. For this reason, a wireless LAN cannot be considered as the primary option for video transmission. These concerns were proven justified via attenuation measurements of the WLAN signal. Nevertheless, WLAN may be used in forming a close range network around the vehicle, for example to connect cameras, computers and PDAs. For longer range video transfer it could be determined that a domestic Ajeco Ltd 4Com multi-channel router is an adequate device. It can be concluded that in order to provide stable, reliable and secure data transfer between vehicles, it is necessary to use wired connections. Wired connections are slower to setup than wireless connections, but wired connections are clearly a better choice due to the numerous challenges that are encountered with wireless connections. For future research it would be worthwile to study the possibilities of long-distance wireless communication methods such as Wi-MAX

Nonplanar spray-coated perovskite solar cells

Spray coating is an industrially mature technique used to deposit thin films that combines high throughput with the ability to coat nonplanar surfaces. Here, we explore the use of ultrasonic spray coating to fabricate perovskite solar cells (PSCs) over rigid, nonplanar surfaces without problems caused by solution dewetting and subsequent "run-off". Encouragingly, we find that PSCs can be spray-coated using our processes onto glass substrates held at angles of inclination up to 45° away from the horizontal, with such devices having comparable power conversion efficiencies (up to 18.3%) to those spray-cast onto horizontal substrates. Having established that our process can be used to create PSCs on surfaces that are not horizontal, we fabricate devices over a convex glass substrate, with devices having a maximum power conversion efficiency of 12.5%. To our best knowledge, this study represents the first demonstration of a rigid, curved perovskite solar cell. The integration of perovskite photovoltaics onto curved surfaces will likely find direct applications in the aerospace and automotive sectors