Despite being the most commonly used hole transport layer for p-i-n perovskite solar cells, the conventional PEDOT:PSS layer is far from being optimal for the best photovoltaic performance. Herein, we demonstrate highly conductive thin DMSO-doped PEDOT:PSS layers which significantly enhance the light harvesting, charge extraction, and photocurrent production of organo-lead iodide devices. Both imaging and X-ray analysis reveal that the perovskite thin films grown on DMSO-doped PEDOT:PSS exhibit larger grains with increased crystallinity. Altogether, these improvements result in a 37% boost in the power conversion efficiency (PCE) compared to standard p-i-n photovoltaics with pristine PEDOT:PSS. Furthermore, we demonstrate that DMSO-doped PEDOT:PSS devices possess enhanced PCE durability over time which we attribute primarily to fill factor stability.

•Formic acid (FA) was used as a novel additive in PTB7:PC71BM based organic solar cells.•The best PCE of 9.04% with 24.6% improvement was obtained with 6 vol% FA doping.•Enhanced PCE was attributed to the increase of exciton generation and enhanced charge-carrier mobility of the devices.Formic acid (FA) was used as a novel additive in bulk heterojunction (BHJ) solar cells, which contains blends 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]thiophene-4,6-diyl]] (PTB7) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM). The effect of FA on the performance of PTB7:PC71BM based BHJ solar cells is investigated. By the incorporation of FA, the device with the ratio of 6 vol % shows the best power conversion efficiency (PCE) of 9.04%, along with the short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF) being 24.11 mA/cm2, 0.72 V, and 52.11%, respectively. Experimental results suggest that FA has a strong influence on charge carrier dynamics with a significant increase in Jsc by ∼65% and the dramatically enhanced PCE is mainly due to the increase of absorption and exciton generation of the active layers and the improved charge-carrier mobility of the devices.

Organic photovoltaics (OPVs) were fabricated with blended active layers 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]-phenylC71-butyric acid methyl ester (PTB7:PC71BM). The active layers were prepared in chlorobenzene (CB) with different additives of 1,8-diiodooctane (DIO) and 1,8-dibromooctane and different concentrations using a wet process with spin coating. The effects of different solvent additives were studied with respect to photovoltaic parameters such as fill factor, short circuit current density, and power conversion efficiency. The absorption and surface morphology of the active layers were investigated by UV-visible spectroscopy, atomic force microscopy (AFM) and time-of-flight secondary ion mass spectrometry (TOF-SIMS), respectively. The results indicated that structural and morphological changes were induced by the solvent additives. The polymer solar cells (PSCs) of PTB7/PC71BM prepared by a spin coating method using DIO and 1,8-dibromooctane showed more improved PCE of 6.76%. The enhancement of performance of PSCs could be mainly attributed to the absorption enhancement and the improved charge carrier transportation.

The effects of MoO3 thin buffer layer on charge carrier injection and extraction in inverted configuration ITO/ZnO/MEH-PPV (poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene))/MoO3 (0, 5 nm)/Ag hybrid solar cells are investigated by capacitance–voltage measurement under dark and light illumination conditions. The efficiency of charge carrier injection and extraction is enhanced by inserting 5 nm MoO3 thin layer, resulting in better device performances. Charge carrier transport of the whole device is improved and the interface energy barrier is reduced by inserting 5 nm MoO3 thin buffer layer. The device fill factor is increased from 54.1 % to 57.5 % after modifying 5 nm MoO3. Simulations and experimental results consistently show that in the forward voltage under dark, the device with the 5 nm MoO3 thin layer modification generates larger value of capacitance than the device without MoO3 layer. While under illumination, the device with the 5 nm MoO3 layer generates smaller value of capacitance than the device without the 5 nm MoO3 layer in the bias region of reverse and before the peak position of maximum capacitance (VCmax). The underlying mechanism of the MoO3 anode buffer layer on device current density–voltage characteristics is discussed.

Wide band gap semi-conductor zinc sulfide (ZnS) nanocolumn arrays were prepared on the glass side of indium tin oxide (ITO) substrates by glancing angle deposition (GLAD) technology. The scanning electron microscopy (SEM) images show the formation of ZnS nanocolumn arrays when the glancing angle was set to 85°; however, continuous ZnS films without any evident nanostructures were fabricated under normal deposition. The transmitting ability of ITO substrates coated with ZnS nanocolumn arrays is improved in comparison to bare ITO substrates and continuous ZnS films coated ITO substrates in the visible range. Organic light-emitting diodes (OLEDs) were simultaneously fabricated on these three kinds of substrates. The electroluminescence (EL) intensity of OLEDs based on the ITO substrate coated with ZnS nanocolumn arrays was about 1.2 times bigger than the devices based on the other substrates (bare ITO substrates and continuous ZnS films coated ITO substrates) under the same driving voltage. The improvement of EL intensity should be ascribed to the enhancement of the light extraction by the nanocolumn arrays effect.

Influences of electric fields on the emission from organic light-emitting diodes (OLEDs) based on poly(N-vinylcarbazole) (PVK) and 4′-bis(2-2diphenylvinyl)-1,1′-biphenyl (DPVBi) as the active emission layer are studied. Electroluminescence (EL) spectra of PVK:DPVBi (1:1 w/w) films show one new emission peak locating at 640 nm compared with its photoluminescence (PL) spectra. There may be exists an electroplex emission between the PVK and DPVBi under high electric field strength. The emission intensity of peaking at 640 nm strongly depends on the driving voltage, and the ratio of electroplex emission intensity to exciton emission intensity (Ielectroplex/Iexciton) increases with the increase of driving voltage.

The microstructural, optical, and magnetic properties and room-temperature photoluminescence (PL) of Mn-doped ZnO thin films were studied. The chemical compositions were examined by energy dispersive X-ray spectroscopy (EDS) and the charge state of Mn ions in the ZnO:Mn films was characterized by X-ray photoelectronic spectrometry (XPS). From the X-ray diffraction (XRD) data of the samples, it can be found that Mn doping does not change the orientation of ZnO thin films. All the films prepared have a wurtzite structure and grow mainly along the c-axis orientation. The grain size and the residual stress were calculated from the XRD results. The optical transmittance of the film decreases with the increase of manganese content in ZnO. The room-temperature photoluminescence of the films shows that the intensity of near band energy (NBE) emission depends strongly on the Mn content. The hysteresis behavior indicates that the films with the Mn content below 9at% are ferromagnetic at room temperature.

The authors report the fabrication of white organic light-emitting devices and discuss their electroluminescence (EL) properties. The device structure is ITO/TPD (50 nm)/BCP (8 nm)/Rubrene (0.5 nm)/BCP (10 nm)/Alq3 (20 nm)/LiF (1 nm)/Al. In the EL spectra of this device, two new emissions peaking at 590 and 630 nm have been observed. These two emissions should be attributed to triplet exciplex and electroplex occurring at TPD/BCP interface. White emission was obtained based on this device under 12 V driving voltage, the Commission Internationale de l’Eclairage (CIE) coordinates arrives to (0.31, 0.33).

Lead zirconate titanate (Pb(Zr0.52Ti0.48)O3, PZT) thin films fabricated by magnetron sputtering technique on the Pt/Ti/SiO2/Si substrates at room temperature, were annealed by means of CO2 laser with resulting average substrate temperature below 500 °C. The crystal structure, surface morphology and pyroelectric properties of the PZT films before and after annealing were investigated by X-ray diffraction, atomic force microscopy, and pyroelectric measurements. The results show that the annealed PZT thin film with a laser energy density of 490 W/cm2 for 25 s has a typical perovskite phase, uniform crystalline particles with a size of about 90 nm, and a high pyroelectric coefficient with 1.15 × 10− 8 Ccm− 2 K− 1.

Organic photovoltaics (OPVs) were fabricated with blended active layers 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]-phenylC71-butyric acid methyl ester (PTB7:PC71BM). The active layers were prepared in chlorobenzene (CB) with different additives of 1,8-diiodooctane (DIO) and 1,8-dibromooctane and different concentrations using a wet process with spin coating. The effects of different solvent additives were studied with respect to photovoltaic parameters such as fill factor, short circuit current density, and power conversion efficiency. The absorption and surface morphology of the active layers were investigated by UV-visible spectroscopy, atomic force microscopy (AFM) and time-of-flight secondary ion mass spectrometry (TOF-SIMS), respectively. The results indicated that structural and morphological changes were induced by the solvent additives. The polymer solar cells (PSCs) of PTB7/PC71BM prepared by a spin coating method using DIO and 1,8-dibromooctane showed more improved PCE of 6.76%. The enhancement of performance of PSCs could be mainly attributed to the absorption enhancement and the improved charge carrier transportation.