Tin-based perovskite is a famous competitor to toxic lead-based perovskite solar cells. Although lead-free perovskite (CH3NH3SnI3) material attracts the attention because of its wider absorption, it ...suffers from temperature instability. Formamidinium tin iodide (HC(NH2)2SnI3– FASnI3) absorber has more temperature stability than CH3NH3SnI3 with wider band gap (1.41 eV). In this work, a device simulation of FASnI3- based solar cells is performed by using SCAPS. Absorber parameters such as thickness, doping concentration and defect density are varied to inspect their impact on device performance. The effect of changing conduction band offset (CBO) and valence band offset (VBO), doping concentration and thickness of electron transport layer (ETL) and hole transport layer (HTL) are also studied. Further, various HTL and ETL candidates are investigated such as CuI, Cu2O, NiO, ZnO and ZnSe. To enhance the cell power efficiency, optimization of the device design key parameters is performed. The initial structure is based on an experimental work having a record of 1.75% efficiency. The final performance parameters of the intended solar cell after enhancing them by the presented parametric study are found to be: a short-circuit current density (Jsc) of 22.65 mA/cm2, open-circuit voltage (Voc) of 0.92 V, fill factor (FF) of 67.74% and power conversion efficiency (PCE) of 14.03%.
•Device modeling of Formamidinium tin-based perovskite solar cell was comprehensively performed.•The impact of physical parameters on the device performance was fully discussed.•After optimization, we obtained: Jsc = 22.65 mA/cm2, Voc = 0.92 V, FF = 67.74% and PCE = 14.03%.•The work promotes future device optimization and performance enhancement.
An organic-inorganic perovskite formamidinium tin iodide (HC(NH2)2SnI3– FASnI3) is used as light absorbing layer in photovoltaics due to its lead-free nature, wider bandgap of 1.41 eV and better ...temperature stability than CH3NH3SnI3. In the present investigations, SCAPS simulation with comparison to the experimental as well as simulation data for FASnI3-based solar cell device is accomplished for high power conversion efficiency with proper optimization. The variation in the device design key parameters such as absorber, hole transport layer and electron transport layer thickness including defect density, doping concentration in absorber, carriers capture cross sections and interfacial defects are examined with their impact on device performance. The preliminary structure of device is based on the reported experimental and simulation work with the efficiency of 1.75% and 1.66%, respectively. After the SCAPS simulation with the optimization of basic parameters in this work, the final optimized performance parameters of the solar cell device are found to be enhanced with short-circuit current density (Jsc) of 31.20 mA/cm2, open-circuit voltage (Voc) of 1.81 V, fill factor (%FF) of 33.72% and power conversion efficiency (%PCE) of 19.08%.
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•Physics behind the performance parameters in (HC(NH2)2SnI3– FASnI3) PSC device.•Comparison FASnI3-based PSC performance with reported experimental and SCAPS simulation results.•Study the effect on the device with the variation of basic parameters of cell.•Final optimized parameters achieved: Jsc-31.20 mA/cm2, Voc-1.81 V, FF-33.72% and PCE-19.08%.
The power conversion efficiency of perovskite solar cells (PSCs) has ascended from 3.8% to 22.1% in recent years. ZnO has been well‐documented as an excellent electron‐transport material. However, ...the poor chemical compatibility between ZnO and organo‐metal halide perovskite makes it highly challenging to obtain highly efficient and stable PSCs using ZnO as the electron‐transport layer. It is demonstrated in this work that the surface passivation of ZnO by a thin layer of MgO and protonated ethanolamine (EA) readily makes ZnO as a very promising electron‐transporting material for creating hysteresis‐free, efficient, and stable PSCs. Systematic studies in this work reveal several important roles of the modification: (i) MgO inhibits the interfacial charge recombination, and thus enhances cell performance and stability; (ii) the protonated EA promotes the effective electron transport from perovskite to ZnO, further fully eliminating PSCs hysteresis; (iii) the modification makes ZnO compatible with perovskite, nicely resolving the instability of ZnO/perovskite interface. With all these findings, PSCs with the best efficiency up to 21.1% and no hysteresis are successfully fabricated. PSCs stable in air for more than 300 h are achieved when graphene is used to further encapsulate the cells.
Surface passivation of ZnO by a thin layer of MgO and protonated ethanolamine readily makes ZnO a very promising electron‐transporting material for creating efficient, hysteresis‐free and stable perovskite solar cells (PSCs). PSCs, stable in air for more than 300 h, are achieved when graphene is used to encapsulate the cells.
Numerical simulations can provide the physical insights into the carrier transport mechanism in the solar cells, and the factors influencing their performance. In this paper, perovskite solar cell ...(PSC) based on the mixed perovskite (CH3NH3Pb(I1-xBrx)3 has been numerically simulated using the SCAPS simulator. A comparative analysis of different electron transport layers (ETLs) based on their conduction band offsets (CBO) has been performed, while Spiro-OMeTAD was used as a hole transport layer (HTL). Among the proposed ETLs, CdZnS performed better and demonstrated the power conversion efficiency (PCE) of 25.20%. Also, the PCE of the PSC has been optimized by adjusting the doping concentrations in the ETL, Spiro-OMeTAD layer, and the thickness of the perovskite light absorber layer. It was found that the doping concentration of 1021 cm−3 for the CdZnS based ETL and 1020 cm−3 for Spiro-OMeTAD are the optimum concentrations values for demonstrating enhanced efficiency. A 600 nm thick perovskite layer has found to be appropriate for the efficient PSC design. For the initial guessing and numerical model validation, the photovoltaic data of a very stable (over one year with PCE ~13%) n-i-p structured (ITO/TiO2/CH3NH3Pb(I1-xBrx)3/Spiro-OMeTAD/Au) PSCs was used. These numerically simulated results signify the optimum performance of the photovoltaic device that can be further implemented to develop the highly efficient PSCs.
•PSC based on the mixed perovskite has been numerically simulated using SCAPS simulator.•A comparative analysis of different ETLs based on their CBOs has been performed.•These numerically simulated results signify the optimum performance of the PSCs.
In recent years, the perovskite solar cells have gained much attention because of their ever-increasing power conversion efficiency (PCE), simple solution fabrication process, flyable, light-weight ...wearable and deployable for ultra-lightweight space and low-cost materials constituents etc. Over the last few years, the efficiency of perovskite solar cells has surpassed 25% due to high-quality perovskite-film accomplished through low-temperature synthesis techniques along with developing suitable interface and electrode-materials. Besides, the stability of perovskite solar cells has attracted much well-deserved attention. In this article we have focused on recent progress of the perovskite solar cells regarding their crystallinity, morphology and synthesis techniques. Also, demonstrated different layers such as electron transport-layers (ETLs), hole transport-layers (HTLs) and buffer-layers utilized in perovskite solar-cells, considering their band gap, carrier mobility, transmittance etc. Outlook of various tin (Sn), carbon and polymer-based perovskite solar cells and their potential of commercialization feasibility has also been discussed.
The energy-levels and charge-transfer process of perovskite solar cells. Display omitted
•The in-depth review of perovskite solar cells were discussed.•Various parameters for solar cell applications were explained.•Stability of perovskite solar cells is discussed.•Commercial applications of perovskite solar cells were illustrated.
•Frontiers in hole and electron transport materials for perovskite solar cell reviewed.•Interface engineering of perovskite solar cell is overviewed.•Advances in device architecture in perovskite ...solar cell is highlighted.•Opportunities future perspective and challenges in perovskite solar cell discoursed.
The breakthrough discovery of organic-inorganic hybrid perovskite materials for converting solar energy into electrical energy has revolutionized the third generation photovoltaic devices. Within less than half a decade of rigorous research and development in perovskite solar cells, the efficiency is boosted upto 22%. Aforesaid high PCE is accredited to high optical absorption properties, balanced charge transport properties, and longer diffusion lengths of carriers. Two dominant perovskite solar cell architecture has evolved; n-i-p, and p-i-n with mesoporous or planar heterojunction. In planar heterojunction configuration, perovskite light harvester is layered between hole/electron transport layers and the electrodes. The electron and hole transporting films increase charge collection efficiency and reduce recombination at interfaces. In the following review, we present a critical survey of the recent progress in perovskite absorber and charge transport materials that account for the exceptionally higher PCE of perovskite devices. Furthermore, numerous fabrication techniques and device architectures are summarized.
Perovskite solar cells (PSCs) have shown unprecedented efficiency progress from 3.8% in 2009 to 24.2% in 2019. Up to now, the highest device efficiencies were recently achieved by employing n-type ...SnO2 on the transparent front electrode with conventional structure (n-i-p structure), while TiO2 remains the most used electron transport layer in PSCs. However, the comparably large J-V hysteresis in planar PSCs and the high temperature process required in mesoporous TiO2 structures severely limit the further commercial application. Therefore, inverted PSCs (p-i-n structure) employing p-type NiOx as the hole transport layer (HTL) on the front electrode have attracted massive attention in recent years. This is mainly due to their lower processing temperature for large scale and flexible devices, negligible J−V hysteresis effects, and furthermore, better stability as compared to organic HTLs. In spite of all these merits of NiOx based HTLs, the reported efficiencies of inverted PSCs are still lower than that of conventional PSCs. The main reasons can be assigned to limitations arising from the low conductivity and a mismatched band position of NiOx. Doping has been considered to be an effective way to adjust the electrical and optical properties of semiconductor oxides in a large extent and has already shown promising results in improving the photovoltaic performance of NiOx based inverted PSCs. In this review, recent investigations about the influence of doping on the structural, electrical, and optical properties of NiOx HTLs are summarized. We also discuss the advantages and current challenges of utilizing NiOx HTLs in PSCs and attempt to give prognoses on future progress exploiting them in high-efficiency inverted PSCs.
Research on planar perovskite solar cells (PSCs) in (inverted) p–i–n configuration, using transparent p-type front-electrodes, is strongly emerging. NiOx has been demonstrated to be one of the most promising candidates to be employed as a hole transport layer (HTL) in these devices, however, its low intrinsic conductivity and unmatched Fermi level with respect to the perovskite layer limit the performance of the PSCs. Extrinsic doping of NiOx HTLs is a versatile and powerful strategy to mitigate these shortcomings, which, within the past three years, led to significantly enhanced power conversion efficiencies (exceeding 20%). In this review, we present a comprehensive overview of the strategies applied to improve the performance of NiOx HTLs used in inverted PSCs with special emphasis on the properties modulation induced by extrinsic doping. Current challenges and perspectives for exploiting these HTLs in high-efficiency inverted PSCs are also given. Display omitted
•Doping strategies of NiOx hole transport layers in perovskite solar cells are reviewed.•Modulation of the properties of NiOx induced by extrinsic doping is highlighted.•Current challenges and perspectives for future progress are given.
An electron‐transport layer (ETL) with appropriate energy alignment and enhanced charge transfer is critical for perovskite solar cells (PSCs). However, interfacial energy level mismatch limits the ...electrical performance of PSCs, particularly the open‐circuit voltage (VOC). Herein, a simple low‐temperature‐processed In2O3/SnO2 bilayer ETL is developed and used for fabricating a new PSC device. The presence of In2O3 results in uniform, compact, and low‐trap‐density perovskite films. Moreover, the conduction band of In2O3 is shallower than that of Sn‐doped In2O3 (ITO), enhancing the charge transfer from perovskite to ETL, thus minimizing VOC loss at the perovskite and ETL interface. A planar PSC with a power conversion efficiency of 23.24% (certified efficiency of 22.54%) is obtained. A high VOC of 1.17 V is achieved with the potential loss at only 0.36 V. In contrast, devices based on single SnO2 layers achieve 21.42% efficiency with a VOC of 1.13 V. In addition, the new device maintains 97.5% initial efficiency after 80 d in N2 without encapsulation and retains 91% of its initial efficiency after 180 h under 1 sun continuous illumination. The results demonstrate and pave the way for the development of efficient photovoltaic devices.
A simple low‐temperature‐processed In2O3/SnO2 bilayer electron‐transport layer (ETL) is used for fabricating efficient perovskite solar cells (PSCs). The bilayer ETL with appropriate energy alignment is beneficial for charge transfer, thus minimizing open‐circuit voltage (VOC) loss. An optimized planar PSC with a power conversion efficiency (PCE) of 23.24% is obtained. In contrast, devices based on single SnO2 only achieve efficiency of 21.42%.
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•FPBA passivate SnO2 defects, reduce non-radiative recombination at ETL/perovskite.•FPBA improve the surface energy of SnO2, which is beneficial to perovskite growth.•Carrier ...separation and transportation are improved due to the formation of dipoles.•The PCE of the Pero-SC was improved from 20.38% to 22.36% upon FPBA modification.•The Pero-SCs with FPBA kept 82% of the initial PCE over 3000 h storage in N2.
SnO2 has recently emerged as a promising Electron transportation layer (ETL) for perovskite solar cells (Pero-SCs). However, its inherent trap-states usually cause charge recombination, and its conductive band does not match well with that of the perovskite film. In order to solve these problems, we herein employed 3,5-Difluorophenylboronic acid (denoted by FPBA) to modify SnO2. After modification, the trap state density of SnO2 is drastically reduced, and better energy-level alignment is formed with perovskite owing to the interfacial dipole of FPBA. Consequently, the champion Power conversion efficiency (PCE) of Pero-SCs is increased from 20.38% to 22.36% after SnO2 being modified with FPBA. Moreover, the unencapsulated device based on FPBA-modified SnO2 maintains 82% of the initial PCE after being stored in nitrogen atmosphere for more than 3000 h.
Bundling of multiple access technologies is currently being standardized by 3GPP in the 5G access traffic steering, switching and splitting (ATSSS) framework, with the goal to increase robustness, ...resiliency and capacity of wireless access. A key part of an ATSSS framework is the packet scheduler, which decides the access network over which each packet is to be transmitted. As wireless channels are highly dynamic, a challenge for any scheduler is to correctly estimate the capacity of each path, and thereby avoid congesting the paths. In this paper, we further develop a recent packet scheduler that exploits cross-layer information from the congestion control state of individual transport layer tunnels when making scheduling decisions. Our aim is to achieve good path utilization while keeping the congestion delay low. Extensive emulations show that our approach reduces the excess delay at the bottleneck to as little as 34%. We furthermore show that our approach improves the performance of end-to-end applications including WebRTC and YouTube compared to state-of-the art.
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