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Nickel oxide (NiOx) has received a lot of attention as an inorganic hole transport material (HTM) in perovskite solar cells (PSCs) during the last decade, owing to its high hole mobility, chemical stability, good optical transparency, and suitable energy levels that align with the valance band of the perovskite absorber methylammonium lead iodide (MAPbI3). This study explores Li and Mg co‐doped NiOx thin films physically‐deposited from developed sputtering targets obtained through cold isostatic pressing and sintering. After sputtering, the structural, elemental, morphological, optical, and electrical properties of the layers are investigated by XRD, XPS, SEM, AFM, UV–vis spectrophotometer, and Hall‐effect; revealing that crystalline, homogeneous, and smooth films are obtained. In particular, improvements in mobility and conductivity values are observed with Li and Mg doping, which contribute to enhanced PSC performance when used as an HTM layer in the glass‐indium tin oxide (ITO)/NiOx‐based HTM/MAPbI3/phenyl butryic acid methyl ester (PCBM)/bathocuproine (BCP)/Ag architecture. The champion solar cell achieves PCE of 15.52%. In addition, the average values of all samples are boosted, JSC (from 13.21 to 15.60 mA cm−2) and FF (from 59.32% to 67.7%), relative to pristine HTM, resulting in a pronounced PCE increment of up to 30% with the HTM film sputtered by a single target of co‐doped material. [ABSTRACT FROM AUTHOR]

Poly (3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) is one of the most commonly used Hole Transporting Materials (HTMs) in a Perovskite Solar Cell (PSC). However, its low conductivity and local charge transport are issues that restrict the device's performance. Moreover, PEDOT:PSS films have many pinholes and are inhomogeneous, leading to increased charge recombination. Thus, these significant drawbacks require an urgent address to enable PSCs to reach their desired efficiency values. In this paper, we have experimented by incorporating a washing technique using Isopropyl Alcohol (IPA). It was observed that the modified device improved the device efficiency to above 11%. The increase in device efficiency can be attributed to better conductivity, smoother charge transfer, superior film quality and improved material compatibility of different PSC components. [ABSTRACT FROM AUTHOR]

Inverted-type perovskite solar cells have drawn remarkable attention due to solution-processable, straightforward configuration, low-cost processing, and manufacturing at very high throughput, even on top of flexible materials. The hole transport material (HTM) plays a vital role to achieve high performance in inverted type of perovskite solar cells. Herein, we report on the effect of different commercial PEDOT:PSS such as PH 1000, PH 500, P VP AI, and P T2, on the performance of CH3NH3PbI3-based planar perovskite solar cells. [ABSTRACT FROM AUTHOR]

In this study, the effects of the various types of PEDOT:PSS with different conductivities on the photovoltaic parameters of organic solar cells were investigated. The performances of five various commercially available PEDOT:PSS with formulations such as FET, PT2, PH1000, PH500 and PH were compared. It was observed that the device employing PH1000 as an interlayer between ITO and the active layer exhibited the highest photovoltaic performance as compared to other devices with FET, PT2, PH500 and PH. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

[Display omitted] • First-time demonstration of Ce and Zn co-doped NiO x layers and employment in inverted perovskite solar cells. • Co-doping with an optimum ratio of Ce and Zn increased the work function, electrical conductivity, hole concentration, and mobility of the NiO x layers. • Enhanced interface quality and decreased trap density in perovskite layer resulted in better device stability. • Fully solution-processed perovskite solar cells fabricated under 50–55% humidity using only γ-butyrolactone employed perovskite precursor for methylammonium lead tri-iodide and record power conversion efficiencies achieved. Cerium and zinc co-doped nickel oxide (NiO x) hole transporter layers (HTLs) developed for boosting the efficiency and stability of inverted methylammonium lead tri-iodide (CH 3 NH 3 PbI 3) based glove box-free fabricated solar cells. Combining our humidity resistive gamma butyrolactone-based perovskite deposition route with an optimum doping ratio of NiO x :Zn-Ce (18:6 mmol %) layers, power conversion efficiencies boosted from 10.04% to 14.47% and stability is increased under aging conditions. This performance enhancement was questioned over NiO x layers, quality of perovskite layer and the interface between charge transport layers and perovskite. Zn doping increased the electrical conductivity while incorporation of Ce created a positive impact on surface morphology and interface quality by a decreased roughness compared to the only Zn doped layers. The work function, hole mobility and concentration were found to increase with co-doping. Besides, the trap density of the perovskite layer is lessened, hindering unfavorable charge recombination confirmed by space charge limited current (SCLC) and photoluminescence (PL) analysis. [ABSTRACT FROM AUTHOR]

• First-time demonstration of Li, Co and Mg-doped NiO x hole transport layers. • Optimum doping with Li, Co, and Mg increased the hole concentration, hole mobility, electrical conductivity, and work function of the NiO x hole transport layers, and perovskite grain sizes thus boosted the photovoltaic performance. • Fully solution-processed glove box free fabrication through γ-butyrolactone based methylammonium lead tri-iodide perovskite precursor resulted in record power conversion efficiencies. Nickel oxide as a popular hole transport material was frequently investigated through, Li, Co, Li-Co and Li-Mg co-doping strategies in the literature. Here, we report a new route based on the synergetic effect of Li-Co-Mg doping for nickel oxide using sol–gel method. For an optimized doping ratio, we observed a clear improvement in the photovoltaic performance of methylammonium lead triiodide (CH 3 NH 3 PbI 3) based inverted perovskite solar cells that were fabricated in ambient air, under high humidity (>50%). Li-Co-Mg doping increased the work function, hole concentration, hole mobility, and electrical conductivity of the NiO x hole transport layers (HTLs). The addition of Co resulted in an undesired drop in the optical transmittance while increasing the surface roughness of the NiO x. It was witnessed that Mg addition healed both the transmittance and interface between HTL and perovskite. Even for the precursor solution, we noticed that by the addition of Mg into the Li and Co-doped NiO x precursor, the solution became more transparent and stable. Photovoltaic measurements revealed that the short-circuit current density increased from 17.3 to 23.9 mA cm−2, the open-circuit voltage was boosted from 0.932 to 1.06 V, and the fill factor was improved from 0.46 to 0.52. Consequently, power conversion efficiencies were found to be increased by up to 13.22% from 7.47% by the Li-Co-Mg doping. We believe our results demonstrate that Li, Co and Mg doping might be a promising way for adapting nickel oxide hole transport layers for CH 3 NH 3 PbI 3 based perovskite solar cells. [ABSTRACT FROM AUTHOR]

• Synthesis and characterization of a novel benzotriazol based small molecule (BTBT). • Evaluation of BTBT molecule as an interlayer in perovskite solar cells. • Low temperature fabrication route using inverted perovskite solar cell geometry. • Achievement of high efficiencies without glove box conditions under high humidity. • Improvement of efficiency using BTBT as an interlayer between ITO and PEDOT:PSS. A novel benzotriazol based small molecule (2-hexyl-4,7-bis(5′-hexyl-2,2′-bithien-5-yl)-2H-1,2,3-benzotriazole) "BTBT" was synthesized by Suzuki coupling reaction and was successfully employed in planar inverted perovskite solar cells with ITO/BTBT/PEDOT:PSS/CH 3 NH 3 PbI 3-x Cl x /PCBM/Al configuration. Fabrication processes, including the spin coating of the perovskite layer, were performed in ambient air, under high humidity conditions (>60%). BTBT/PEDOT:PSS bilayer notably improved the power conversion efficiencies (PCE) from 9.65% to 11.6%, which corresponds to an increase of 20%. [ABSTRACT FROM AUTHOR]

Organic bulk heterojunction and inverted type solar cells were fabricated using AnE-PVstat:PCBM blends as photoactive layers. The device was inverted using thin films of TiO 2 as hole blocking and electron conducting layers. The power conversion efficiency (PCE) of organic bulk heterojunction solar cells increased from 1.70% to 2.59% when inverted device configuration was used instead of regular organic bulk heterojunction solar cell configuration. Stability studies reveal that the inverted type devices are more stable than the herein investigated regular organic bulk heterojunction solar cells fabricated using AnE-PVstat:PCBM blends as photoactive layers. [ABSTRACT FROM AUTHOR]

In this report, two novel donor-acceptor-donor type triphenylamine-quinoxaline-based (QC-TPA and QC-TPAOMe) small organic molecules have been synthesized by the Suzuki coupling reaction as hole transport materials (HTMs) and successfully utilized in the NiO x /perovskite interface. All device fabrication steps with ITO/NiO x /QC-TPA or QC-TPAOMe/CH 3 NH 3 PbI 3 /PCBM/BCP/Ag configurations were performed in ambient air over 55% relative humidity, except for thermal evaporation of metal contacts. Modifications of the NiO x /perovskite interface with QC-TPA and QC-TPAOMe molecules can improve FF and J SC by enhancing hole extraction and reducing energy losses. Consequently, the power conversion efficiency (PCE) boosted from 10.03% to 14.46% and 13.21% with surface modifications of NiO x with QC-TPA and QC-TPAOMe, respectively. [Display omitted] • Novel donor-acceptor-donor small organic molecules as interlayers in perovskite solar cells. • Interface materials are used to passivate interface defects and eliminate pinholes. • Modifications of the interface improve hole extraction and reduce energy losses. [ABSTRACT FROM AUTHOR]

We fabricated bulk heterojunction (BHJ) solar cells with a configuration ITO/PEDOT:PSS/P3HT:PCBM:o-SWNT/Al that consisted of different carbon nanotubes concentrations functionalized with octadecylamine (o-SWNT). The three solar cells which consisted of o-SWNT concentrations of 0.01%, 0.001% and 0.0001% by weight were prepared at the same process conditions. The absorption measurements of active layer (P3HT:PCBM: x wt% of o-SWNT) and current–voltage measurements of solar cells have shown that V OC does not change depending on the used contribution rates. However, J SC has increased by 23.8% in solar cells that are fabricated with o-SWNT concentrations of 0.001 wt% compared with solar cell without o-SWNT. The power conversion efficiency has also increased by 31.8%. While IPCE is about 37% in 350 nm in the reference solar cell, IPCE of the solar cell comprised of o-SWNT of 0.001 wt% is about 45%. [ABSTRACT FROM AUTHOR]

Abstract: This paper is devoted to the development of inverted-type bulk heterojunction solar cells based on zinc oxide (ZnO) interlayers, poly-3-hexylthiophene (P3HT) and PCBM using simple synthesis procedures and deposition techniques. We compare device structures and performances consisting of poly-3-hexylthiophene (P3HT) polymer and PCBM in contact with three different types of ZnO interlayers: a ZnO backing interlayer alone using spin coating process; nanorod ZnO interlayers from Zn2+:HO− solutions using deep coating process and finally nanorod ZnO interlayers from Zn2+:HO− solutions onto ZnO backing interlayer using spin coating process. The best device configuration is fabricated in a ZnO backing interlayer/nanorod ZnO interlayer by spincoating process/P3HT:PCBM/Gold cell architecture which exhibits a power conversion efficiency of 2.73% under 100mW/cm2 AM 1.5G simulated solar emission. Atomic force microscopy (AFM) and photovoltaic device measurements are used to study the morphology and device performance of the three different types of ZnO interlayers. [Copyright &y& Elsevier]

Poly (3,4-ethylenedioxythiophene)-poly (styrene sulfonate (PEDOT:PSS) is a widely-known conductive polymer mixture that is mostly engaged as a hole transport layer (HTL) in organic and perovskite solar cells (PSCs). In this study, it has been demonstrated that the use of Zn as an additive in PEDOT:PSS solution improved the photovoltaic performance of the ambient air solution-based fabrication of methylammonium lead tri-iodide (MAPbI 3) based devices. The short circuit current density (J SC) of the device increased from 15.4 to 17.2 mA/cm2, while the fill factor (FF) improved from 0.70 to 0.83 by using Zn-doped PEDOT:PSS as a hole transport layer (HTL), which is a record value for only γ-butyrolactone (GBL) based MAPbI 3 PSCs. Additionally, open-circuit (V OC) value is boosted up from 890 to 925 mV by Zn-doping, which might be linked to the increased work function of the investigated HTLs. Moreover, the synergetic effect of improved electrical conductivity and hole mobility of PEDOT:PSS film and decreased the trap density of perovskite led to an increase of 37% in power conversion efficiency (PCE) and the stability of the inverted planar PSCs. [ABSTRACT FROM AUTHOR]