Inverted Device Research Articles

Stereo-Hindrance Induced Conformal Self-Assembled Monolayer for High Efficiency Inverted Perovskite Solar Cells.

Self-assembled monolayers (SAMs) are employed as hole-selective contacts in inverted perovskite solar cells (PSCs) and have achieved record power conversion efficiency (PCE) over 26%. However, the tendency of extensively employed SAM [2-(3,6-Dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid to aggregate leads to its uneven coverage to the transparent conducting oxide substrate, which subsequently compromises the photovoltaic performance. Herein, a novel tert-butyl functionalized phosphonic acid carbazole SAM is developed, i.e., (4-(3,6-di-tert-butyl-9H-carbazol-9-yl)butyl)phosphonic acid (tBu-4PACz), and introduced to a mixed SAM system as the hole-extraction layer in inverted PSCs. The stereo-hindrance of the bulky tert-butyl group prevents undesired aggregation and leads to better conformality, which facilitates more efficient hole-extraction and suppresses interfacial recombination losses. The tBu-4PACz SAM-based inverted PSC has achieved record level PCE of 26.25% (26.21%, certificated) with outstanding fill factors over 86%. Moreover, the mixed SAM based inverted PSC devices maintained over 94.7% of their initial efficiency after 500h continuous maximum power-point tracking under simulation 1-sun irradiation.

Robust non-fragile hybrid control for delayed uncertain singular impulsive jump systems based on improved impulse instant-dependent auxiliary functions method

This article researches the issue of robust non-fragile hybrid control for delayed uncertain singular impulsive jump systems (USIMJSs). The key aim is to design non-fragile hybrid state feedback controllers (including a non-fragile normal state feedback controller and a non-fragile impulsive state feedback controller), which are insensitive to the uncertainties of gains of controllers and can provide sufficient tuning margins. The non-fragile normal state feedback controller can eliminate the internal impulses and overcome the external disturbances; the non-fragile impulsive state feedback controller can suppress the interference of external unstable impulses and restrain the instantaneous jumps caused by Markovian modes switching. By introducing impulse instant-dependent auxiliary functions, the improved impulse-time-dependent Lyapunov–Krasovskii functional is constructed, which can capture the information of the impulse instants and Markovian jump modes. Novel criteria of robust admissibilization for delayed USIMJSs are acquired under linear matrix inequalities framework. Lastly, the effectiveness of the derived algorithm and designed method is confirmed by simulation examples including a direct current motor-controlled inverted pendulum device and a Quarter-Car active suspension model.

Continuous Isothermal Antisolvent Crystallization of Pyrazinamide in a Coiled Flow Inverter Device

Continuous Isothermal Antisolvent Crystallization of Pyrazinamide in a Coiled Flow Inverter Device

Non-Ionic Perylene-Diimide Polymer as Universal Cathode Interlayer for Conventional, Inverted, and Blade-Coated Organic Solar Cells.

As a class of predominantly used cathode interlayers (CILs) in organic solar cells (OSCs), perylene-diimide (PDI)-based polymers exhibit intriguing characteristics of excellent charge transporting capacity and suitable energy levels. Despite that, PDI-based CILs with satisfied film-forming ability and adequate solvent resistance are rather rare, which not only limits the further advance of OSC performances but also hinders the practical use of PDI CILs. Herein, we designed and synthesized two non-conjugated PDI polymers for achieving high power conversion efficiency (PCE) in diverse types of OSCs. The utilization of oligo (ethylene glycol) (OEG) linkage enhanced the n-doping effect of PDI polymers, leading to an improved ability of the CIL to reduce work function and improve electron transporting capability. Moreover, the introduction of the non-ionic OEG chain effectively improve the wetting property and solvent resistance of PDI polymers, so the PPDINN CIL can withstand diverse processing conditions in fabricating different OSCs, including conventional, inverted and blade-coated devices. The binary OSC with conventional structure using PPDINN CIL showed a PCE of 18.6 %, along with an improved device stability. Besides, PPDINN is compatible with the large-area blade-coating technique, and a PCE of 16.6 % was achieved in the 1-cm2 OSC where a blade-coated PPDINN was used.

Outcomes of fenestrated and branched endovascular aneurysm repair with an inverted contralateral limb

ObjectiveTo report technical success and evaluate clinical outcomes of fenestrated and branched endovascular aortic repair (F/B-EVAR) incorporating a contralateral inverted limb. MethodsPatients who underwent F/B-EVAR with a custom-made bifurcated device containing an inverted limb between January 2010 and September 2023 were retrospectively analyzed. Time-to-event data were analyzed using the Kaplan-Meier method. ResultsA total of 32 patients (26 men; mean age 77±6.2 years) were included in the analysis. Technical success was achieved in 28 patients (87.5%). Two technical failures resulted from misplaced contralateral limbs in patients with previous endovascular aortic repair (EVAR), necessitating one open conversion due to a type 3b endoleak, and one femoro-femoral crossover bypass after occlusion of a misplaced contralateral limb. Additionally, two technical failures were attributed to a type 3c endoleak and a type 1c endoleak, originating from a fenestrated device at the level of the left and right renal artery, respectively. One patient (3.1%) died <30 days post-operatively due to a subdural hemorrhage. Estimated patient survival after 1 and 2 years was 92.7%±5.1%, and 74.3%±10.1%, respectively. No aneurysm-related deaths were observed. During the median follow-up of 13 months, one (3.1%) inverted limb occluded, in addition to the occlusion resulting from a misplaced contralateral limb, and was treated with a femoro-femoral crossover bypass. One target vessel (right renal artery) occluded (0.9%), resulting in a permanent, significantly reduced renal function. Freedom from overall reintervention after 1 and 2 years was 73.5%±8.0% and 68.3%±9.0%, respectively. An additional four patients (12.5%) presented with a type 3c endoleak during follow-up scans, three of which originated from fenestrations at the level of the renal stents. There were no junctional problems between the inverted limb device and the main endograft, and no significant correlation was found between the one-sealing-stent inverted limb device design and the onset of type 3 endoleak (log-rank p=.064). ConclusionF/B-EVAR incorporating an inverted limb can be a viable endovascular option to manage complex aneurysms with a short renal artery to bifurcation distance. However, using the inverted limb presents a notable technical challenge and could be associated with a higher need for reintervention. Carefully confirming correct cannulation of the inverted limb is warranted.

Interfacial layer with a dibenzofulvene-bridged triphenylamine core for efficient and stable inverted perovskite solar cells

Considering the energy level cascade, introducing a hole transport layer (HTL) between the NiOx and perovskite layers has become a common and effective strategy to enhance the performance of inverted perovskite solar cells (PSCs). Herein, we designed and synthesized three hole-transporting interfacial layers (TPAD, TPAO, and TPAS) based on a dibenzofulvene-bridged triphenylamine (TPA) core to fabricate efficient and stable inverted NiOx-based PSCs. Dibenzofulvene, known for its sp²-hybridized structure, offers superior planarity and molecular stacking, and it easily bonds with triphenylamine derivatives, resulting in unique light-harvesting and charge mobility properties for optoelectronic applications. Specifically, diphenylamine, dimethoxy diphenylamine, and dimethylthio diphenylamine were used as end-capping units for TPAD, TPAO, and TPAS, respectively. The NiOx-based inverted PSC devices fabricated with TPAS as an interfacial layer effectively modified NiOx to improve energy level alignment, enhance film quality and crystallinity, and improve carrier transport, leading to a high-quality perovskite layer and superior interface contact behavior. Consequently, this device yielded a highly efficient cell performance of 20.30 %, surpassing those using TPAD (19.29 %) and TPAO (18.78 %) as interfacial layers, and significantly outperforming devices using only NiOx (17.69 %). Additionally, the champion cell exhibited negligible hysteresis and long-term stability. These findings demonstrate a facile approach to preparing multifunctional TPA-based hole transport materials and showcase the efficient performance of inverted cells based on a triphenylamine dibenzofulvene-based interfacial layer, contributing to the development of high-efficiency inverted PSCs.

A universal hole transport layer for efficient organic solar cells processed by blade coating

Doctor-blade coating technology is a roll-to-roll compatible high-throughput thin film fabrication route. In this work, doctor-blading was applied for fabricating organic solar cells (OSCs) using a polyoxometalates material phosphomolybdic acid (PMA) as a hole transport layer (HTL). Compared to PEDOT:PSS, PMA-based devices demonstrate lower trap-assisted recombination, higher hole mobility, prolonged charge carrier lifetime and faster charge collection. With PM6:Y6 as active layer, PMA-based device delivered a high power conversion efficiency (PCE) of 17.79 % with a boosted short-circuit current density (JSC) value of 28.08 mA/cm2, which is one of the best performances for PM6:Y6-based solar cells through doctor-blading process. In addition, the performance improvement was observed in both conventional and inverted structured devices with various donor: acceptor combinations. These results indicate the high universality of PMA for printable processing and its prospect in preparation of the industrial production of OSCs.

Early experience with patient-specific unibody bifurcated fenestrated-branched devices for complex endovascular aortic aneurysm repair

ObjectiveShort distances between the lowest visceral/renal artery and the aortic bifurcation are technically challenging during complex endovascular aortic aneurysm repair (EVAR), particularly after previous infrarenal repair. Traditionally, inverted limb bifurcated devices have been used in addition to fenestrated-branched (FB) endografts, but short overlap, difficult cannulation, and potential crushing of bridging stents are limitations for their use. This study reviews the early experience of patient-specific company manufactured devices (PS-CMDs) with a unibody bifurcated FB design for complex EVAR. MethodsConsecutive complex EVAR procedures over a 34-month period with unibody bifurcated FB-devices as part of physician-sponsored investigational device exemption studies at two institutions were reviewed. Unibody bifurcated FB designs included FB bifurcated or fenestrated inverted limb devices. End points included technical success, survival, frequency of type I or III endoleaks, limb occlusion, and secondary interventions. ResultsAmong 168 patients undergoing complex EVAR, 33 patients (19.6%; 78.7% male; mean age, 77 years) received unibody bifurcated FB PS-CMDs. FB bifurcated and fenestrated inverted limb devices were used in 31 (93.9%) and 2 (6.06%) patients, respectively. The median maximum aneurysm diameter was 61 mm (interquartile range [IQR], 55-69 mm). Prior EVAR was reported by 29 patients (87.9%), of whom 2 (6.06%) had suprarenal stents. A short distance between the lowest renal artery and aortic bifurcation was demonstrated in 30 patients (90.9%), with median distance of 47 mm (IQR, 38-54 mm). Preloaded devices were used in 23 patients (69.7%). A total of 128 fenestrations were planned; 22 (17.2%) were preloaded with guidewires and 5 (3.9%) with catheters. The median operative time was 238 minutes (226-300 minutes), with a median fluoroscopy time of 65.5 minutes (IQR, 56.0-77.7 minutes) and a median dose area product of 147 mGy∗cm2 (IQR, 105-194 mGy∗cm2). Exclusive femoral access was used in 14 procedures (42.4%). Technical success was 100%. Target vessel primary patency was 100% at a median follow-up time of 11.7 months (IQR, 3.5-18.6 months). Two patients (6.06%) required reintervention for iliac occlusion; one patient required stenting and the other a femoral-femoral bypass. No aortic-related deaths occurred after the procedure. During follow-up, 11 type II endoleaks (33.3%) and 1 type Ib endoleak (3.03%) were detected; the latter was treated with leg extension. No type Ia or III endoleaks occurred. ConclusionsComplex EVAR using unibody bifurcated FB-PS-CMDs is a simple, safe, and cost-effective alternative for the treatment of patients with short distances between the renal arteries and the aortic bifurcation. Further studies are required to assess benefits and durability of unibody bifurcated FB devices.

Inverted device architecture for high efficiency single-layer organic light-emitting diodes with imbalanced charge transport

Many wide-gap organic semiconductors exhibit imbalanced electron and hole transport, therefore efficient organic light-emitting diodes require a multilayer architecture of electron- and hole-transport materials to confine charge recombination to the emissive layer. Here, we show that even for emitters with imbalanced charge transport, it is possible to obtain highly efficient single-layer organic light emitting diodes (OLEDs), without the need for additional charge-transport and blocking layers. For hole-dominated emitters, an inverted single-layer device architecture with ohmic bottom-electron and top-hole contacts moves the emission zone away from the metal top electrode, thereby more than doubling the optical outcoupling efficiency. Finally, a blue-emitting inverted single-layer OLED based on thermally activated delayed fluorescence is achieved, exhibiting a high external quantum efficiency of 19% with little roll-off at high brightness, demonstrating that balanced charge transport is not a prerequisite for highly efficient single-layer OLEDs.

Regulating the perovskite/C60 interface via a bifunctional interlayer for efficient inverted perovskite solar cells

Inverted perovskite solar cells are promising candidates in photovoltaic fields due to their low-temperature processing, simplified fabrication, and enhanced stability when compared with the conventional configuration. However, the significant non-radiative recombination losses and energy alignment mismatch at the perovskite/C60 interface limit the device's performance and long-term stability. To overcome this drawback, we introduced trifluoromethoxy-functionalized phenethylammonium iodide salts with high polarity between the perovskite and C60 electron transporting layer. This bifunctional interlayer not only effectively passivates the perovskite surface and interface but also reduces the minority carriers through the band rearrangement at this interface, thus significantly suppressing the deteriorating interfacial non-radiative recombination. The modified interlayer also facilitates electron extraction by reducing the offset between the perovskite and C60, contributing to an improved photocurrent and fill factor. The resultant inverted perovskite solar cell based on a Cs0.05FA0.85MA0.10Pb(I0.95Br0.05)3 composition reveals a power conversion efficiency of 24.7 % at the reverse scan and shows negligible efficiency loss after 600 h of maximum power point tracking under one-sun illumination. Overall, this feasible deposition of ammonium-based interlayer establishes a successful demonstration of efficient and stable inverted devices to accelerate the commercialization of perovskite photovoltaics.

Holistic dielectric and buffer interfacial layers enable high-efficiency perovskite solar cells and modules

Suppressing the interfacial non-radiative recombination plays a critical role in reducing the voltage loss of perovskite solar cells. Herein, we develop a holistic interfacial regulation using dielectric materials of Al2O3 and PEABr/PMMA, and a buffer layer of compact SnOX to manipulate the multiple interfaces. A compact SnOX is inserted to reduce the charge accumulation at the interface of electron transport layer/Ag. Through this multiple interfacial design, the power conversion efficiency is greatly increased from 22.66% to 25.70% (certified 24.23%), mainly attributing to much enhancement in open circuit voltage and fill factor. The fill factor of 86.41% is the highest among the self-assembled-monolayers-based inverted devices. Both perovskite film and resulting device show increased thermal stability due to the incorporation of compact SnOX, which inhibits the escape of volatile species from perovskite, infiltration of moisture and the suppression of ion migration. Scaling up this strategy delivers an efficiency for a minimodule as high as 21.56%. More importantly, we discovered that the PEABr passivation could induce the collapse of morphology under continuous illumination, thus leading to worse operational stability. This work provides a path towards omnibearing modification for minimizing the trap-assisted recombination at the interface through the synergetic effects of dielectric materials.

Discontinuous PWM Strategy for Reliability and Efficiency Improvements of Single-Phase Five-Level T-Type Inverter

Reliability and efficiency improvements of PV inverters have a high potential to decrease the cost of PV energy. Discontinuous PWM is an effective method to improve both the efficiency and reliability of the power devices of the single-phase five-level T-type NPC inverter. However, applying DPWM gives a negative effect on the lifetime of the DC-link capacitors and thus reduces the reliability of the inverter from the system-level reliability point of view. This paper proposes the DPWM strategy to improve the lifetime of the DC-link capacitor compared with the conventional DPWM method so that both the reliability and efficiency of the single-phase five-level T-type NPC inverter are improved. Through the proposed strategy, the lifetime of the DC-link capacitor is improved, but its negative effects on the efficiency of the inverter and the lifetime of the power devices are negligible. Therefore, the advantages of applying DPWM can be sustained. Simulation and experimental results verify the feasibility and effectiveness of the proposed DPWM strategy.

A novel fuzzy-logic controller-MDsUPQC topology for power quality improvement in multi-feeder distribution system

In the current situation, the significant usage of massive non-linear functioned power electronic loads has been increased in domestic and industrial applications. The main problem of power-quality (PQ) deterioration in both voltage quality and current quality from nominal values and also damaging the single/multi feeder distribution systems. The major contribution is to alleviate the PQ issues by employing novel multi-devices unified power-quality conditioner (MDsUPQC) topology in a multi-feeder distribution system. This MDsUPQC comprises multiple voltage source inverter (VSI) devices connected with a common direct current-link (DC-link) capacitor which is controlled by a proportional-integral (PI) controller. However, this controller has some technical issues that are not suited for the regulation of common DC voltage at the desired level because of improper selection of gain values. The contribution of this work is proposing an intelligent fuzzy-logic (FL) DC-link controller-driven MDsUPQC device which evidences the intelligent knowledge base for better regulation of PQ issues. The technique and performance of the suggested strategy for PQ improvement, load sharing between feeders, and simulation results are presented with comparative analysis utilizing the MATLAB/Simulink software tool.

Fluorinated organic ammonium salt passivation for high-efficiency and stable inverted CsPbI2Br perovskite solar cells.

All-inorganic CsPbI2Br inverted perovskite solar cells (PSCs) have drawn increasing attention because of their outstanding thermal stability and compatible process with tandem cells. However, relatively low open circuit voltage (Voc) has lagged their progress far behind theoretical limits. Herein, we introduce phenylmethylammonium iodide and 4-trifluoromethyl phenylmethylammonium iodide (CFPMAI) on the surface of a CsPbI2Br perovskite film and investigate their passivation effects. It is found that CFPMAI with a -CF3 substituent significantly decreases the trap density of the perovskite film by forming interactions with the under-coordinated Pb2+ ions and effectively suppresses the non-radiative recombination in the resulting PSC. In addition, CFPMAI surface passivation facilitates the optimization of energy-level alignment at the CsPbI2Br perovskite/[6,6]-phenyl C61 butyric acid methyl ester interface, resulting in improved charge extraction from the perovskite to the charge transport layer. Consequently, the optimized inverted CsPbI2Br device exhibits a markedly improved champion efficiency of 14.43% with a Voc of 1.12V, a Jsc of 16.31 mA/cm2, and a fill factor of 79.02%, compared to the 10.92% (Voc of 0.95V) efficiency of the control device. This study confirms the importance of substituent groups on surface passivation molecules for effective passivation of defects and optimization of energy levels, particularly for Voc improvement.

Interfacial Regulation toward Efficient CsPbBr3 Quantum Dot-Based Inverted Perovskite Light-Emitting Diodes.

Inverted perovskite light-emitting diodes (PeLEDs) based on quantum dots (QDs) are some of the most promising candidates for next-generation lighting and display applications. Due to the strong fluorescence quenching caused by zinc oxide, high performance in such inverted devices remains challenging. Here, we report an efficient inverted green CsPbBr3 QDs LED using an emitting buffer layer. Ultrathin CsPbBr3 QD emitters act as the buffer layer to reduce the interface luminescence quenching reaction at the ZnO/upper emitting layer interface, increasing the probability of exciton recombination within the emissive layer and regulating the charge transport, leading to effective carrier recombination. The resulting device exhibits an external quantum efficiency of 13.1%, enhanced by about 4.7 times compared with that without a buffer layer device. This work provides a path to fabricating high-performance inverted PeLEDs.

Sequential Deposition Processing to Control Vertical Composition Distribution toward High‐Performance and Stable Inverted Organic Solar Cells

AbstractSequential deposition (SD) is widely applied in the fabrication of high‐performance organic solar cells (OSCs). Nevertheless, the feasibility of SD in inverted photovoltaic devices is rarely mentioned. Moreover, the vertical component distribution in SD‐processed devices is still under debate. This study demonstrates that SD can achieve the entire bulk heterojunction morphology by precisely controlling the morphology of the active layer. To further promote photovoltaic performance, two post treatments, thermal annealing (TA) and solvent vapor annealing (SVA), are conducted to compare their effects on SD‐processed inverted photovoltaic devices. The results verify that SD can significantly enhance the thermal stability of devices. This work provides a valuable insight for systematically understanding SD processing and the preparation of stable inverted OSCs with superior performance.

Single Phase Inverter Design for Solar Panel Output Voltage

Inverter is a devices that functions to convert DC input voltage to AC. One technique for optimizing the inveter output is SPWM. In this final project, a single–phase SPWM inverter with bipolar SPWM switching is designed. This inverter has 1 phase H-Bridge spesifications, with IGBT components, resistors, warehouse and inductors where there are 4 MOSFETs that can be connected. By carrying out 3 test with different sources for a 244.44 volt DC source it produces 0,47 % harmonic, a variable DC source produces 54,81 % harmonics and for a PV sources 9,91 % harmonics. Of the three test, the largest harmonic value is by using a variable DC source. Large harmonic can affect the shape of the wave to be non-sine and the wave has lots of ripples. This simulation aims to facilitate the design of real inverter devices.

Improved Air Stability for High-Performance FACsPbI3 Perovskite Solar Cells via Bonding Engineering.

Despite the fact that perovskite solar cells (PSCs) are widely popular due to their superb power conversion efficiency (PCE), their further applications are still restricted by low stability and high-density defects. Especially, the weak binding and ion-electron properties of perovskite crystals make them susceptible to moisture attack under environmental stress. Herein, we report an overall sulfidation strategy via introduction of 1-pentanethiol (PT) into the perovskite film to inhibit bulk defects and stabilize Pb ions. It has been confirmed that the thiol groups in PT can stabilize uncoordinated Pb ions and passivate iodine vacancy defects by forming strong Pb-S bonds, thus reducing nonradiative recombination. Moreover, the favorable passivation process also optimizes the energy-level arrangement, induces better perovskite crystallization, and enhances the charge extraction in the full solar cells. Consequently, the PT-modified inverted device delivers a champion PCE of 22.46%, which is superior to that of the control device (20.21%). More importantly, the PT-modified device retains 91.5% of its initial PCE after storage in air for 1600 h and over 85% of its initial PCE after heating at 85 °C for 800 h. This work provides a new perspective to simultaneously improve the performance and stability of PSCs to satisfy their commercial applications.

Fullerene-C60 and PCBM as interlayers in regular and inverted lead-free PSCs using CH3NH3SnI3: an analysis of device performance and defect density dependence by SCAPS-1D.

One of the challenges hindering the commercialization of perovskite solar cells (PSCs) is the presence of toxic metals such as lead in their composition. Simulation studies using SCAPS-1D have already been conducted on lead-free PSCs to find optimized solar cell parameters, having tin as the primary candidate for replacing lead in perovskites. Here, we used fullerene-C60 and its derivative PCBM as interlayers in a lead-free tin-based PSC between the ETL (ZnO) and the perovskite MASI in both regular and inverted configurations of PSCs using SCAPS-1D software. To the best of our knowledge, this is the first simulation study reporting the impact of using fullerene-C60 and PCBM as interlayers in lead-free PSCs. The defect density (Nt) of the perovskite material is varied, allowing us to observe its influence on the power conversion efficiency (PCE). Using an Nt value of 1017 cm-3 without the interlayer, the PCE was 6.90% and 3.72% for regular and inverted devices. Using PCBM as an interlayer improves the efficiency of both simulated PSCs, achieving a maximum PCE of 8.11% and 5.26% for the regular and inverted configurations, respectively. Decreasing the Nt from 1017 cm-3 to 1016 cm-3 caused a significant increase in efficiency, reaching 13.38% (n-i-p) and 10.00% (p-i-n). Finally, using the optimized parameters and an ideal Nt value (1013 cm-3), both PSCs achieved a PCE close to 30%.

A donor:hole-transport layer alloy for high-efficiency and stable binary organic solar cells with promoted hole collection and suppressed recombination

A donor-based nanoparticle (NPs)-incorporated hole-transport layer was synthesized for fine-tuning the energy level of anodes in organic solar cells. The conventional and inverted devices achieved record efficiencies of 19.9% and 17.2%, respectively.