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Sb2Se3 is a promising absorber material for thin-film solar cells owing to its earth-abundant and non-toxic constituents, superior optoelectronic properties, and unique one-dimensional crystal structure. To further increase the power conversion efficiency of the Sb2Se3, we fabricated an n-i-p structure by integrating a solution-processed NiOx hole-transport layer (HTL) into Sb2Se3 solar cells to enhance the carrier collection. In this study, we systematically screen the thickness of NiOx HTL and demonstrate an improved average power conversion efficiency from 6.12% to 7.15% with a 50 nm NiOx HTL. The mechanism associated with the improved device performance was characterized through the microstructure of the material, device physics, and interface electronic behaviors. It is also shown that the low-cost and scalable solution-processed NiOx HTL can improve device stability under an accelerated stress test. Thus, this work paves a way to further improve the performance of antimony chalcogenides-based solar cells via tailoring the inorganic HTL.

A new molecular precursor for Cu2ZnSnS4 (CZTS) has been explored for the fabrication of efficient superstrate type solar cells with all solution processed functional layers at low temperature. The CZTS film made at low temperature (250 °C), without sulfurization was employed in the heterojunction device with a thin interface layer of CdS and the one-step hydrothermally processed rutile TiO2 nanorod arrays. The quality of the CZTS film was optimized by varying the composition of Cu and Zn in the precursor solution. Initial devices with (FTO/TiO2/CdS/CZTS/Au) structure exhibited the power conversion efficiency up to 1.04%, on par with the best in the relevant literature.

In the present paper, we report the effect of annealing temperature on optical properties of solution processed As2S3 Chalcogenide Glass (ChG) films. Solution processing of ChG films is a low cost, low temperature, scalable route for deposition of high quality films. Annealing of solution processed ChG films is a crucial step for the removal of residual solvent from the films. The optimization of the annealing temperature and corresponding optical properties of ChG films helps in better utilization of these films in functional devices. As2S3 glass was synthesized using melt quenching. The as-prepared As2S3 glass was dissolved in n-butylamine. The solution was then deposited onto glass substrates in the form of thin films. The as-prepared As2S3 glass films were annealed at different temperatures. As-annealed As2S3 glass films were studied using UV-Visible Spectroscopy, Infrared (IR) Spectroscopy, X-ray diffraction (XRD), Raman Spectroscopy and Energy Dispersive X-ray (EDAX) spectroscopy to undestand the effect of annealing on the structural and optical properties of the films

All solution-processed semi-transparent perovskite solar cells (PSCs) with high efficiency were fabricated with Ag nanowire (AgNW) top electrode directly coated on the organic electron transport layer (ETL). A unique AgNW/ETL interface morphology was attained by the fabrication of the AgNW-C60 composite electrode through a sequential spin-coating method. The C60 filler spin-coated on the AgNW network engendered a high contact area and favourable energy level alignment at the interface between the ETL and AgNW. As a result, devices based on AgNW-C60 electrode far outperformed devices with pristine AgNW electrodes. By adjusting the thickness of the AgNW film, the AgNW-C60 devices attained a PCE of 11.02%. The incorporation of C60 into the AgNW electrode also led to remarkable stability improvement. The low-temperature solution-processed and semi-transparent AgNW-C60 top electrode is also applicable to other PSC structures with various interfacial layers, thus showing a promising path towards fully-printable, flexible and translucent photovoltaic devices.

The effects of hydrogen peroxide (H2O2) on the device properties and stabilities of solution-processed AlOx metal-oxide-semiconductor capacitors (MOSCAPs) were investigated. It is demonstrate. d that H2O2 is a strong oxidizer to decompose precursor residuals, reduce oxygen vacancy (Vo) and defects density of solution-processed AlOx thin films. The interface quality and the bias-stress (BS) stability of AlOx MOSCAPs were improved by employing H2O2. Furthermore, through carrying out on-site measurements, 7.5 M H2O2 AlOx MOSCAPs exhibited ignorable radiation-induced oxide traps and interface traps under biased-radiation-stress (BRS) with a total dose up to 42 Gy (SiO2). The 7.5 M H2O2 AlOx MOSCAPs also demonstrate the ability to recover under radiation after the bias was interrupted. The reduced number of Vo and high AlOx concentration of 7.5 M H2O2 AlOx could suppress the radiation-induced trapping/de-trapping behavior among the AlOx bulk and the breaking of Si–H bonds at the AlOx/Si interface. Besides, through biased-illumination-stress (BIS) measurements, the breaking of Si–H bonds under negative biased-radiation-stress (NBRS) was further proved. The results demonstrate that employing H2O2 in the solution-process is simple and effective; it has significant potential to improve the stabilities of large-area electronics for nuclear and aerospace applications.

To achieve green solution-processed thermally activated delayed fluorescence (TADF) organic light emitting diodes (OLEDs) with low turn-on voltages and high power efficiencies (PEs), an interfacial exciplex system 4,4′-N,N′-dicarbazolylbiphenyl (CBP)/(1,3,5-triazine-2,4,6-triyl)tris(benzene-3,1-diyl)tris(diphenylphosphineoxide) (PO-T2T) was used as the host to sensitize TADF emitters. Due to barrier-free hole-electron injection and effectively energy transfer, green solution-processed OLED with interfacial CBP:PO-T2T host exhibits a low turn-on voltage of 3.0 V and maximum current efficiency (CE), PE and external quantum efficiency (EQE) of 53.4 cd/A, 41.9 lm/W and 16.2% by using our previous reported TADF molecule 2’-(10H-phenoxazin-10-yl)-[1,1’:3′,1″-terphenyl]-4,4″,5′-tricarbonitrile (oPTBC) as the emitter. And the compared OLEDs based on the bulk CBP:PO-T2T host and single CBP host exhibit relatively high turn-on voltages of 4.3 and 3.7 V and low maximum PEs of 20.8 and 33.0 lm/W. Moreover, the OLED based on classic green TADF emitter 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) achieves high performance with an ultralow turn-on voltage of 2.9 V and high maximum CE, PE and EQE of 67.2 cd/A, 62.1 lm/W and 20.0%, respectively. These results are remarkable among the reported green solution-processed TADF-OLEDs and demonstrate the superiority of interfacial exciplex host in solution-processed OLEDs.

We report on the synthesis of perovskite Cs2SnI6 films via the solution–processed approach. The cubic Cs2SnI6 phase (Fm3m group) formed at the annealing temperature of 170 °C for 8 h in air has uniform morphology. The optical characteristics of the compound depended on the annealing temperature and the compound behaved like a direct band gap semiconductor. Based on these findings, we firstly investigated the potential application of Cs2SnI6 to photoelectrochemical (PEC) water splitting using a 0.3 M NaCl electrolyte. The photocurrent density (PCD) and photoconversion efficiency (η) were 0.92 mA cm−2 and 0.54% at −0.8 V, respectively. This might be suitable for fabricating the hybrid PEC device.

Although metal nanoparticles (NPs) have been widely reported, Au NPs functionalized reduced graphene oxide (rGO)/GaN nanorods (NRs) for multi-functional applications are rarely discussed. The rGO is a well known transparent electrode and has been considering an alternative electrode to ITO in the current optoelectronic community. In this work, Au NPs functionalized rGO (Au@rGO)/GaN NRs hybrid structure probed for photodetector and CO gas sensing applications. The hybrid structure was characterized by scanning electron microscopy, transmission electron microscope, current-voltage characteristics, photo conductivity, and gas sensor measurements. The Au@rGO/GaN NRs showed higher photoresponsivity (λ = 382 nm, 516 nm) compared to rGO/GaN NRs at room temperature. The rising and falling times of Au@rGO/GaN NRs are faster than that of rGO/GaN NRs. The hybrid structure Au@rGO/GaN NRs exhibited high CO gas response compared to rGO/GaN NRs at room temperature (∼38% to the 20 ppm). Au NPs played an important role in terms of electronic and chemical changes in the hybrid structure for improving both photodetectors the CO gas response. Such a multi-functional hybrid device is an interest of various room temperature applications.

Two acceptor-donor1-donor2-donor1-acceptor (A-D1-D2-D1-A)-type narrow bandgap small molecules BDT(IDT-IC)2 and BDT(IDT-IC-2F)2 with indacenodithiophene–benzodithiophene-indacenodithiophene (BDT-(IDT)2) as donating cores and 2-(3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (IC) or 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene) malononitrile (2FIC) as end groups, have been synthesized and investigated as non-fullerene acceptors in solution-processed polymer solar cells (PSCs). The optical bandgaps of BDT(IDT-IC)2 and BDT(IDT-IC-2F)2 are 1.59 eV and 1.54 eV, respectively. Using PBDB-T as donor, the power conversion efficiencies (PCEs) of 4.98% and 6.21% are achieved by PSCs based on BDT(IDT-IC)2 and BDT(IDT-IC-2F)2, respectively.

Solution processed blue phosphorescent organic devices based on mixed host system were fabricated in this paper. A set of blue phosphorescent organic light emitting diodes (PhOLEDs) utilizing two small molecular materials of 3,3-Di(9H-carbazol-9-yl) biphenyl (mCBP) and 4,4′,4′′-tris(N-carbazolyl)-triphenylamine (TCTA) as mixed host doped with phosphor bis[(4,6-difluorophenyl)-pyridina-to-N,C2](picolinate) iridium(III) (FIrpic) are fabricated. The results show that the performance of mixed host system devices is improved compared with two single host devices. The max luminance of 23,340 cd/m2 is achieved in the mCBP:TCTA (2:1) mixed host device while the 14,400 cd/m2 in mCBP single host devices and the 12,968 cd/m2 in TCTA, and the current efficiency is improved from 8.17 cd/A(mCBP), 9.61 cd/A (TCTA) to 13.62 cd/A at the luminance of 1000 cd/m2. The transient electroluminescence measurement was utilized to detect the carrier injection between two kinds of PhOLEDs and penetrate how the trap charges works in the mixed host devices. This presents that the mixed host system contributes to the hole injection and the equilibrium of the carrier transport, reduces trapped charges, thus brings about high efficiency devices.

An investigation of field emission on solution processed MWCNTs, MoS2 and MoS2 anchored MWCNTs thin films on low cost stainless steel substrates have been performed. Decorative morphology of MoS2 nanoflakes over MWCNTs interconnected high surface area nanonetwork supports the active path for the application of field emission. Drastic diminishing in turn-on field value has been obtained for MWCNTs/MoS2 nanocomposite compared to bare MWCNTs and MoS2. Hence, present investigation opens path for the development of low-temperature solution processed MWCNTs/MoS2 thin film in the field of nanoelectronics and the used process can be integrated for large scale.

High triplet energy of exciplex was achieved successfully by modifying conventional electron-donating (D) molecule TCTA. So, in this work, Ph-O-TCTA was designed and synthesized. Ph-O-TCTA: PhPO could efficiently form an exciplex. The solution-processed blue phosphorescent and thermally activated delayed fluorescent (TADF) OLEDs have been realized with the maximum current efficiencies above 30 cd A−1 by employing exciplex Ph-O-TCTA: PhPO as a host.

Conventional phosphorus anode materials in lithium/sodium-ion batteries are mainly based on the physical mixing and evaporation/condensation, in which external phosphorus on conductive matrix is unavoidable and hard to be removed due to the formation of crystalline phase. It has been found to break off from conductive matrix easily and deteriorate capacity rapidly. In this communication, we first report a solution processed encapsulation method which facilitates phosphorus anchored inside multi-walled carbon nanotubes (MWCNTs). Any possible external phosphorus adsorbents are hard to transform into crystalline and enable an easy removal by polar solvents. Eventually, the phosphorus rings and chains are successfully encapsulated only inside MWCNTs, exhibiting high cycling stability in lithium-ion battery because of the efficient physical confinement and unique discrete phosphorus segment assemblies inside MWCNTs which ensured enough vacant space for volume expansion.

Lanthanide organic complexes have high color purity with 100% theoretical internal quantum efficiency, making them good candidates for applications in organic light emitting devices. However, highly efficient and stable solution-processed devices based on terbium complexes have not been reported yet. Here, we present a solution-processed OLED using a novel terbium complex based on pyrazolone derivative ligand with pronounced efficiency. The device with co-host of 70% TcTa and 30% OXD-7 showed low turn-on voltage of 2.30 V, maximum current efficiency of 17.16 cd A−1 and external quantum efficiency of 7.15% at 1000 cd m−2. In addition, presenting a reduced roll-off efficiency compared to other reported terbium complex devices. This high efficiency for solution-processed Tb-based OLEDs clearly indicates the potential application of this Tb-complex in display applications.

Reduction of graphene oxide becomes an alternative way to produce a scalable graphene and the resulting nanomaterial namely reduced graphene oxide (rGO) has been utilized in a wide range of potential applications. In this article, the level of green reduction strategies, especially the solution-based reduction methods are overviewed based on recent progression, to get insights towards biomedical applications. The degrees of gaining tips with the solution-based green reduction methods, conditions, complexity and the resulting rGO characteristics have been elucidated comparatively. Moreover, the application of greenly produced rGO in electrochemical biosensors has been elucidated as well as their electrical performance in term of linear range and limit of detections for various healthcare biological analytes. In addition, the characterization scheme for graphene-based materials and the analyses on the reduction especially for the solution-based green reduction methods are outlined for the future endeavours.

Optimal interfaces play an important role in determining the efficiency of perovskite solar cells. Despite nickel oxide is a promising hole transport material in perovskite solar cells, electrical conductivity and surface properties of pristine nickel oxide are not satisfactory for achieving high efficiency perovskite solar cells. Here, we demonstrate that cobalt doping significantly improves not only the electrical conductivity but also the interfaces of nickel oxide hole transport layer. As a result, the hole extraction, transport and collection properties are significantly improved in the device using cobalt-doped nickel oxide as a hole transport layer. Also, it reveals that cobalt-doped nickel oxide reduces the trap-sites of interfaces of perovskite/hole transport layer, leading to suppressed charge recombination in the devices. As a result, the devices using cobalt-doped nickel oxide achieve as high as 17.52% without severe hysteresis, which is attributed to better band alignment, superior hole extraction and decreased resistance, as compared to pristine nickel oxide-based devices.

For decades, inorganic n-type metal-oxide semiconductors have attracted great interest across a wide range of applications due to their excellent electrical property, low cost, high optical transparency, and good ambient stability. The next attention has focused on the development of high-performance p-type semiconductors with comparable opto/electric properties to n-type counterparts. This paper provides a comprehensive overview of recent progress in solution-processed inorganic p-type semiconductors that can be applied as channel layers in thin-film transistors and complementary metal-oxide semiconductor-based integrated circuits. We first introduce conventional p-type oxide semiconductors and review their achievements on related devices. Then, we pay a specific focus on emerging (pseudo)halide materials for realization of transparent, low-temperature and high-performance printable electronics and circuits.

This paper reports the hydrazine-free solution processing of antimony doping in CuIn(S,Se)2 solar cells using thiol-amine as solvents. The Sb-doped CuIn(S,Se)2 absorbers layer is fabricated using low-cost atmospheric spray deposition route. The morphological, optical, and electrical properties of Sb-doped CuIn(S,Se)2 are investigated using XRD, FE-SEM, UV–Vis-IR spectrophotometer, and solar simulator. Results suggest that the power conversion efficiency of fabricated CuIn(S,Se)2 solar cells is significantly improved by introducing antimony dopant. Results infers plausible way of future manufacturing and processing of chalcopyrite thin films solar cells at lower temperature using non-vacuum deposition route.

A solution-processed NiO-dye-ZnO photocathode was developed for applications in both solid-state p-type dye-sensitized solar cells (p-ssDSCs) and p-type dye-sensitized photoelectrosynthesis cells ( ...

An alcohol additive 1, 8-Octanediol (ODO) with a simple carbon chain structure was first introduced into the light-emitting layer (LEL) of solution-processed small molecule organic light-emitting diodes (OLEDs) in this work. We found a typical host material of CBP presented a micro-aggregation film state with low percent of ODO adding in the LEL. The corresponded solution-processed devices with the LEL of CBP and 4CzIPN were investigated. The reduced device turn-on voltage and improved efficiency was achieved with low percent addition of 2 wt% ODO in LEL. Moreover, in the atmosphere, the device with ODO additive showed alleviated device degradation compared to no additive device. These results demonstrate the micro-aggregated state of the host is helpful, which can be attributed to the better charge transfer ability. Significantly, this additive process was also applied to other devices with reduced device turn-on voltage and improved efficiency.

Surface recombination of photogenerated carriers turned to be critical issues against the realization of high-performance nanowire-based solar cells. To overcome it, the strategy toward passivating nanowire surfaces was essential where the improvement of minority carrier lifetime was identified in recent years; instead, the examinations of optical management as well as charge-transfer resistance at heterojunction were still limited. In this study, we herein investigated the facile, inexpensive and reliable HNO3-based chemical passivation that directly introduced SiOx coating on Si nanowires. By adjusting the oxidation durations, the cell performance exhibited the improved conversion efficiency with more than 39% of efficiency enhancement than reference cells. Impacts of light harvesting and charge separation characteristics on cell performances were in-depth envisioned.

Unlike ordinary organic field-effect transistors (OFETs), saturation current is hardly to be found in vertical OFETs (VOFETs). Moreover, the fabrication process of patterned sourced for VOFETs is quite complex. In this current work, a simple solution processed VOFET with directly deposited intermediate silver source electrode has been demonstrated. The VOFET exhibits a high leakage current that induces an inversion polarity of its transistor behavior. Interestingly, a well-defined saturation current was observed in the linear scale of transfer characteristic. The VOFET operated with high-current density >280 mA/cm2 at Vd = 5 V. Overview potential of the fabricated device in display application is also presented. This preliminary work does open-up a new direction in VOFET fabrication and their application.

We report a nonvolatile-memory device based on solution-processed Hf-doped ZnO (ZnO:Hf) thin-film transistors (TFTs) fabricated by inserting SiO2 microparticles (MPs) and nanoparticles (NPs) as a charge trapping medium. The transfer characteristics of ZnO:Hf TFT devices inserted with SiO2 particles showed a large clockwise hysteresis behavior owing to charge carrier trapping capability. Both memory devices exhibited a highly programmable memory window during the program/erase operation, which can be attributed to charge carrier trapping and de-trapping in SiO2 particles. Particularly, the memory device with SiO2 NPs revealed a larger memory window over 25 V than that with MPs. Furthermore, the fabricated memory devices showed remarkably long-term retention characteristics and the ON/OFF current ratio greater than 104.

We reported the low-temperature high performance IGZO TFTs by solution processing. The influence of IGZO composition over broad range on thin films and devices properties were investigated by a wide range of characterization techniques. The schematic of TFT solution-processed IGZO TFTs mobility with different compositions has been obtained. In order to achieve decent TFT performance, the In content should be much high for solution-processed IGZO TFTs. The optimal solution-processed IGZO TFTs with In:Ga:Zn = 5:1:1 composition exhibited a large mobility of 9.1 cm2 V−1 s−1, low subthreshold swing of 0.22 V/decade, and high on/off ratio of 106 at 300 °C processing temperature.

In this work, we demonstrate the chemical optimization of benzo[1,2-b:4,5-b′]dithiophene (BDT)-5,6-difluorobenzo-[2,1,3]thiadiazole (FBT) D-A alternating copolymer for obtaining the efficient polymeric donors for the environment-friendly solution processed polymer solar cells (PSCs). Three polymers PBTF, PBTTF-C6 and PBTTF-H, in which one or two alky thiophene units are inserted into the backbone of BDT-FBT alternating copolymer, present much different performances either in the PSCs processed from halogenated solvent and additive or in the PSCs processed from non-halogenated solvent and additive. With an alky thiophene and a bare thiophene as the spacer, PBTTF-H performs best among the three. Especially when the devices processed from 1,2,4-trimethylbenzene and diphenyl ether, in which the highest PCE of 6.80% is achieved with a VOC of 0.77 V, a JSC of 13.67 mA cm−2 and a FF of 64.2%. We think these results will cast light on developing new polymeric donors of the green-solvent-processed PSCs.

In perovskite solar cells , inorganic hole transport materials have attracted intense attention because of the properties of high chemical stability, hole mobility and low cost. However, most of the inorganic hole conductors exhibit low performance compared with organic hole transport materials. In this study, a facile solution method was developed to prepare a V 2O5 film combined with P3CT-K thus forming a bilayer structure as hole transport layers in inverted CH3NH3PbI3 solar cells. It was found that the hole transport bilayer not only increased the rate of extraction charge but also reduced charge recombination compared with the P3CT-K only based device. As a result, the power conversion efficiency of inverted CH3NH3PbI3 solar cells based on the bilayer was boosted up to the optimal value of 19.7% (average value: 19.0%). Furthermore, the device maintained an efficiency of more than 86% through one-month follow-up, in which the dense and hydrophobic V2O5 film accounted for the improved device stability.

In this study, solution-processed blue organic light-emitting diodes (OLEDs) were constructed by employing POBPCz as a bipolar host material with a high triplet of 3.01 eV and 2CzPN as the blue TADF emitter. A maximum EQE of 12.9% was realized in the blue TADF OLEDs, along with a satisfactory CIE coordinate of (0.19, 0.37). These results were among the best ones for the 2CzPN-based solution processed blue OLEDs. Moreover, solution-processed white OLEDs (WOLEDs) with a single-emitting layer were fabricated by Ir(MDQ)2 (acac) as the orange-red iridium complex. The optimized WOLEDs could achieve a maximum EQE of 12.4%, as well as the stable electroluminescence spectra. Notably, the white-light emission was achieved by the incomplete energy transfer from the blue TADF emitter of 2CzPN to the orange-red emitter of Ir (MDQ)2 (acac) via Forster energy transfer (FRET) process.

Na has been believed to improve the device parameters of open circuit voltage (VOC) and fill factor (FF) presumably by increasing the carrier concentration (NA) of vacuum-processed Cu(In,Ga)Se2 films. In solution-processed CI(G)Se devices as well, Na reportedly increases VOC and FF but this improvement is not correlated with the increase in NA, suggesting a different physical mechanism associated with Na in solution-based routes. In this contribution, experimental results on the role of Na addition in solution-processed CISe films and devices were reported, in which Na addition had no influence on NA nor on film composition in spite of the notable increase in the device efficiency. On the contrary, Na was found to mitigate the interfacial recombination by reducing the undesirable surface defects. Along with this understanding, Na addition in our air-processable route resulted in a CISe device with 12.83% efficiency, which is comparable to the current world record efficiency of solution-processed CISe devices.

In this work, we report Copper Sulfide (CuS) as a solution processed, inexpensive and effective hole transport layer (HTL) for efficient and low cost organic solar cells. These devices were fabricated using two most studied low band gap donor materials PTB7 and PCDTBT blended with PC71BM as an acceptor material. We have used a simplest device architect such as ITO/CuS/active layer/Al at ambient conditions. The power conversion efficiencies (PCEs) of these devices have been achieved to up to 4.32% and1.76 % for PTB7 and PCDTBT based devices respectively. Finally, we have provided a further example of solution processable CuS as an effective HTL for solution processable organic photovoltaic applications.

Interfacial buffer layer is a primary requirement for highly efficient and stable organic solar cells (OSCs) and has become a significant part of OSC research today. Here, highly dispersed functionalized reduced graphene oxide (FGr) was obtained as a stable electron buffer layer (EBL) for high-performance conventional solar cells. The power conversion efficiency of FGr-based devices (9.47% for PTB7-Th:PC71BM and 4.05% for P3HT:PC71BM) outperforms PFN-based devices (8.94% and 3.52%). Furthermore, the stability of the devices was greatly improved with FGr as EBL compared to PFN, and only dropped 7.4% of its original value after stored for 61 days. The results indicate that solution-processed functionalized reduced graphene oxide is a promising interfacial material and an excellent candidate as electron buffer layer.

Organic electronics is one of the most promising technologies for creating flexible electronic devices using low temperature plastic compatible processes. However, contact resistances of organic transistors remain one of the most significant hurdles to achieving high performance circuits in this technology. Short channel devices (

In this study, we employed microwave irradiation (MWI) at low temperature in the fabrication of solution-processed AlZnSnO (AZTO) resistive random access memory (ReRAM) devices with a structure of Ti/AZTO/Pt and compared the memory characteristics with the conventional thermal annealing (CTA) process. Typical bipolar resistance switching (BRS) behavior was observed in AZTO ReRAM devices treated with as-deposited (as-dep), CTA and MWI. In the low resistance state, the Ohmic conduction mechanism describes the dominant conduction of these devices. On the other hand, the trap-controlled space charge limited conduction (SCLC) mechanism predominates in the high resistance state. The AZTO ReRAM devices processed with MWI showed larger memory windows, uniform distribution of resistance state and operating voltage, stable DC durability (>10 3 cycles) and stable retention characteristics (>10 4 s). In addition, the AZTO ReRAM devices treated with MWI exhibited multistage storage characteristics by modulating the amplitude of the reset bias, and eight distinct resistance levels were obtained with stable retention capability.

Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) hole contact is widely used in organic solar cells (OSCs). In this work, we report the effort to develop a versatile solution-processed molybdenum trioxide (s-MoO3)/Au nanoparticles (NPs)/s-MoO3 (MAM) hole contact for application in PEDOT:PSS-free OSCs. The use of Au NPs is to improve the adhesion between the two s-MoO3 layers in the MAM hole contact. It shows that MAM hole contact enables to enhance the charge extraction through suppression of bimolecular recombination, and reduce the leakage current by improvement of contact property. Power conversion efficiency of 7.68% was obtained for MAM-based OSCs, with a blend system of poly[[4,8-bis[(2-ethylhexyl) oxy]benzo[1,2-b: 4,5-b’] dithiophene-2,6-diyl] [3-fluoro-2-[(2-ethylhexyl) carbonyl] thieno[3,4-b]-thiophenediyl]]: [6,6]- phenyl-C70-butyric-acid-methyl-ester, which is comparable to that of the PEDOT:PSS-based cells (7.48%). It demonstrates clearly that solution-processed MAM hole contact can be readily adopted to replace the widely used acidic PEDOT:PSS hole contact for application in PEDOT:PSS-free OSCs.

A double-layer organic photodetector with solution-processed interconnecting layers composed of a spin-coated ZnOx layer and a spray-coated poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidine (Poly-TPD) layer is fabricated. The result showed that the double-layer device effectively suppresses the dark current by 2 orders of magnitude, compared to its single layer counterpart. Interestingly, the photocurrent under reverse bias also significantly increased. As a result, the double-layer photodetector showed high on/off ratio of 2.6 × 104 and the detectivity is up to 6.5 × 1012 Jones at −1.5 V. The strategy of spin-coating combining with spray-coating sequentially to form solution-processed interconnecting layers can be an effective and facile way to produce high-detectivity solution-processible organic photodetectors.

The approach towards the increase of the terbium electroluminescence efficiency by the increase of the transport properties was further developed. Therefore, terbium-based emitters, containing anionic ligands, able to both increase the hole mobility and to sensitize terbium luminescence, were purposefully obtained within the composite films, containing the recently studied host material PO4, able to increase electron-transport properties and also to ensure terbium luminescence. As a result, the luminance of 332 cd/m2 was reached, which is one of the highest results for solution-processed OLEDs based on terbium complexes.

Flexible organic field-effect-transistor (OFET) memory is one of the promising candidates for next-generation wearable nonvolatile data storage due to its low price, solution-processability, light-weight, mechanically flexibility, and tunable energy level via molecular tailoring. In this paper, we report flexible nonvolatile OFET memory devices fabricated with solution-processed polystyrene-brush electret and organic semiconductor blends of p-channel 6, 13-bis-(triisopropylsilylethynyl)pentacene (TIPS-PEN) and n-channel poly-{[N,N′-bis(2- octyldodecyl)-naphthalene-1,4,5,8-bis-(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (P-(NDI2OD-2T); N2200). Fabricated flexible OFET memory devices exhibited high memory window (30 V) and ON/OFF current ratio (memory ratio) over 103. Furthermore, we obtained reliable memory ratio (~103) over retention time of 108 s, 100 times of repeated programming/erasing cycles, and 1000 times of bending tests at a radius of 3 mm.

Organic light-emitting diodes (OLEDs) fabricated with thermally activated delayed fluorescence materials usually suffer from serious efficiency roll-offs at high voltages, which restrain their practical applications. To address this issue, in this work, we design and synthesize two luminogens composed of electron-withdrawing benzoyl, electron-donating phenoxazine and 9,9-dimethyl-9,10-dihydroacridine, and dendritic tris(4-(9H-carbazol-9-yl)phenyl)amine. The thermal stabilities, energy levels, electronic structures, photophysical properties and electroluminescent performance of both luminogens are investigated and discussed. They display enhanced fluorescence with greatly increased delayed component under aggregated states, demonstrating the aggregation-induced delayed fluorescence property. Vacuum-deposited and solution-processed OLEDs were fabricated by using both luminognes as emitters, which provided high external quantum efficiencies of 16.9% and 10.7%, respectively, with the negligible efficiency roll-offs.

Multilayer organic light-emitting diodes (OLEDs) produced by the fully solution-processed method without the dissolution of subsequent layers are necessary to achieve cost-effective high performance devices. Although photo-cross-linkable organic molecules and orthogonal solvents are regarded as promising approaches to avoiding dissolution, fully solution-processed multilayer OLEDs do not demand their use, making it impossible to investigate them and limiting their progress. In this work, a simple technique by means of hot wind that requires only a spin coater and a heat gun and reduces the dissolution problem is developed to produce fully solution-processed multilayer OLEDs. Results show that the average current efficiency is about 18 cd/A and the external quantum efficiency is 6% for devices with areas of 0.4 × 0.4 and 1.4 × 1.4 cm2.

In this work, the impact of donor material on the optical and photodiode response is revealed by comparing the performance of self-powered photodiodes based on D:Alq3 (D=TPD or NPD) composite. The active layers were fabricated from solution-processed composites using the well-known spin coating technique, followed by their optical and electrical characterizations. The photodiodes were utilized for the UV light detection in a self-powered mode, in which no external power is required, but it is generated through the photovoltaic effect. Results showed that the NPD film has provided a broader and more intensive optical absorption towards the UV light compared to that of TPD. Also, photoluminescence quenching in the NPD:Alq3 composite was found to highly outperform that of the TPD:Alq3. These were ascribed to the effect of extra pi conjugated bonds present in the NPD, which are originated from the aromatic rings. Consequently, the NPD:Alq3 photodiodes presented a respective sensitivity, responsivity and detectivity of 1.3×105, 1.07 mA/W and 5.25×1011 Jones at 0 V. Moreover, the response (0.34 s) and recovery time (0.28 s) of these devices were found to be smaller compared to those reported in literature.

In this work, W-doped TiO2, was successfully fabricated, as electron transport layer (ETL) in perovskite solar cells (PSCs) via low-temperature solution-processed method, whose outstanding performances were verified. The experimental results reveal that, W6+ was doped into the TiO2 lattice successfully. The improved ETL exhibit significantly improved on conductivity, transport and extraction of photo-generated carriers and less trap-state density as compared with the pristine TiO2 films. Meanwhile, strengthening the velocity of carrier and collection of sufficient charge can efficiently increase short-circuit current (JSC) which favor an improved fill factor (FF) and a higher power conversion efficiency (PCE). Our optimized cation–anion-mixed PSC based on W-doped TiO2 has achieved an efficiency of 18.85%. This improved PCE is almost 28.1% higher than that of the pure TiO2. This study provides a promising approach to design metal-doped TiO2 for fabricating high-performance perovskite solar cells.

Chalcogenide Glasses (ChGs) are technologically promising materials widely used in different optical, electronic and optoelectronic applications. Solution processing of ChGs has provided a pathway for less complex thin film processing of these materials and their integration into flexible devices. This paper reviews the basic science behind the solution processing of ChGs, properties of solution processed ChG films and recent functional applications of solution processed ChGs. Solution processing of ChGs also provides the facile method of incorporation of nanostructures into ChG matrix which integrate the functional properties of nanostructures and ChGs in a single solution or thin film. This paper also reviews the research work undertaken on the incorporation of nanostructures in ChGs.

Two new acceptor-donor-acceptor small molecules DINDTS and DINCNDTS, with dithienosilole as a core unit and 1,3-indanedione (IN) or malononitrile derivative 1,3-indanedione (INCN) units as end-capped groups, respectively, have been designed and synthesized for solution-processable bulk-heterojunction (BHJ) solar cells. The impact of these two end-capped groups on their optical, electrochemical properties and photovoltaic performance was systematically studied. The optimal DINDTS:PC 71 BM based solar cells showed a short-circuit current density ( J sc ) of 13.50 mA cm −2 and power conversion efficiency (PCE) of 6.60%. However, DINCNDTS:PC 71 BM based devices exhibited a poor PCE of 0.58% with a very low J sc of 1.82 mA cm −2 , which are mainly due to its poor morphology of active layers.

Low dimensional nanomaterials have emerged as candidates for gas sensors owing to their unique size-dependent properties. In this paper, Bi2S3 nanobelts were synthesized via a facile solvothermal process and spin-coated onto alumina substrates at room temperature. The conductometric devices can even sensitively response to the relatively low concentrations of NO2 at room temperature, and their sensing performance can be effectively enhanced by the ligand exchange treatment with inorganic salts. The Pb(NO3)2-treated device exhibited superior sensing performance of 58.8 under 5ppm NO2 at room-temperature, with the response and recovery time of 28 and 106s. The competitive adsorption of NO2 against O2 on Bi2S3 nanobelts, with the enhancement both in gas adsorption and charge transfer caused by the porous network of the very thin Bi2S3 nanobelts, can be a reasonable explanation for the improved performance at room temperature. Their sensitive room-temperature response behaviors combined with the excellent solution processability, made Bi2S3 nanobelts very attractive for the construction of low-cost gas sensors with lower power consumption.

Under the synergistic effect of molecular design and devices engineering, small molecular organic solar cells have presented an unstoppable tendency for rapid development with putting forward donor-acceptor (D-A) structures. Up to now, the highest power conversion efficiency of small molecules has exceeded 11%, comparable to that of polymers. In this review, we summarize the high performance small molecule donors in various classes of typical donor-acceptor (D-A) structures and discuss their relationships briefly.

Interface engineering for the improved injection properties of all-solution-processed n-type organic field-effect transistors (OFETs) arising from the use of an inkjet-printed ZnO electron injection layer were demonstrated. The characteristics of ZnO in terms of electron injection and transport were investigated, and then we employed ZnO as the electron injection layer via inkjet-printing during the fabrication of all-solution-processed, n-type OFETs. With the inkjet-printed ZnO electron injection layer, the devices exhibited approximately five-fold increased mobility (0.0058 cm2/V s to 0.030 cm2/V s), more than two-fold increased charge concentration (2.76 × 1011 cm−2 to 6.86 × 1011 cm−2), and two orders of magnitude reduced device resistance (120 MΩ cm to 3 MΩ cm). Moreover, n-type polymer form smoother film with ZnO implying denser packing of polymer, which results in higher mobility.

The poor air-stability and reproducibility of perovskite solar cells (PSCs) have prevented the practical applications of the devices that can withstand sustained operation under ambient air conditions. Here, we report all-ambient-air-solution-processed PSCs based on CH3NH3PbI3−xClx-NiO composite film with inserting Al2O3/NiO at the TiO2/perovskite interface in a cell configuration of FTO/c-TiO2/mp-TiO2/Al2O3/NiO/MAPbI3−xClx-NiO/spiroOMeTAD/Au. The interface engineering with Al2O3/NiO not only improves crystalline quality of perovskite films and enhances charge transport, but also effectively suppresses carrier recombination. This composite-based interface engineering PSCs showed a high power conversion efficiency (PCE) of 18.14% and excellent reproducibility with average 16–18% PCE for 35 devices. More importantly, the devices without encapsulation showed a significant enhancement in long-term air-stability; the device photovoltaic parameters stabilized after 20 days and sustained its stability over 210 days with retaining ~100% of its original Voc, ~94% of Jsc, ~91% of FF and ~86% of PCE in an ambient environment.

We propose a flexible proximity sensor to detect sub-centimeter distance with an ultra-high displacement resolution. The proximity sensor is realized by integrating a semi-transparent organic photo detector with a transparent top electrode and a finger-type bottom electrode. By placing the semi-transparent finger-type photodetector on a light source, such as a light-emitting diode (LED), the photodetector can detect the light reflected from an object on top of the sensor. With the highly compact structure, the detecting range is from 1 mm to 30 mm. From 1 mm to 10 mm, the sensor is particularly sensitive and delivers a resolution of 1 mm. The air-stable photodetector can also be fabricated on a flexible substrate without encapsulation, enabling the integration with arbitrary light sources. After 1000 times bending, the flexible photodetector shows no obvious degradation.