•Au and Ag mix NPs are codeposited on indium-tin-oxide substrates by thermal evaporation method.•Cooperative plasmon enhanced small molecule organic solar cells are fabricated based on Au:Ag NPs.•A 22.5% enhancement in PCE is demonstrated.•The improvement is contributed to the increased Jsc and the increased conductivity of the device.•Factors are investigated to determine the PCE of cooperative plasmon enhance organic solar cells.Cooperative plasmon enhanced small molecule organic solar cells are demonstrated based on thermal coevaporated Au and Ag nanoparticles (NPs). The optimized device with an appropriate molar ratio of Au:Ag NPs shows a power conversion efficiency of 3.32%, which is 22.5% higher than that of the reference device without any NPs. The improvement is mainly contributed to the increased short-circuit current which resulted from the enhanced light harvesting due to localized surface plasmon resonance of Au:Ag NPs and the increased conductivity of the device. Besides, factors that determining the performance of the Au:Ag NPs cooperative plasmon enhance organic solar cells are investigated, and it finds that the thickness of MoO3 buffer layer plays a crucial role. Owing to the different diameter of the thermal evaporated Au and Ag NPs, a suitable MoO3 buffer layer is required to afford a large electromagnetic enhancement and to avoid significant exciton quenching by the NPs.Download high-res image (144KB)Download full-size image

•Au NPs are deposited on indium-tin-oxide substrates by thermal evaporation method.•All thermal evaporated surface plasmon enhanced OSCs are fabricated by using these Au NPs.•A 14% enhancement in PCE is demonstrated.•The improvement is attributed to the increased absorption due to LSPR of Au NPs and the conductivity of the devices.Au nanoparticles (NPs) are fabricated on indium-tin-oxide substrates by a thermal evaporation method and incorporated to an efficient small molecule organic solar cell (OSC). This renders an all thermal evaporated surface plasmon enhanced OSC. The optimized device shows a power conversion efficiency of 3.40%, which is 14% higher than that of the reference device without Au NPs. The improvement is mainly contributed to the increased short-circuit current which resulted from the enhanced light harvesting due to localized surface plasmon resonance of Au NPs and the increased conductivity of the device.

A solution processed MoO3/PEDOT:PSS bilayer structure is used as the hole transporting layer to improve the efficiency and stability of planar heterojunction perovskite solar cells. Increased hole extraction efficiency and restrained erosion of ITO by PEDOT:PSS are demonstrated in the optimized device due to the incorporation of an MoO3 layer.

High-performance panchromatic organic photodetectors (OPDs) containing small molecules lead phthalocyanine (PbPc) and C70 fullerene as donor and acceptor, respectively, were demonstrated. The OPDs had either a PbPc/C70 planar heterojunction (PHJ) or a PbPc/PbPc:C70/C70 hybrid planar-mixed molecular heterojunction (PM-HJ) structure. Both the PHJ and the PM-HJ devices showed a broad-band response that covered wavelengths from 300 to 1100 nm. An external quantum efficiency (EQE) higher than 10% and detectivity on the order of 1012 Jones were obtained in the wavelength region from 400 to 900 nm for the PHJ device. The EQE in the near-infrared region was enhanced by using the PM-HJ device structure, and a maximum EQE of 30.2% at 890 nm was observed for the optimized device with a 5% PbPc-doped C70 layer. Such an EQE is the highest at this wavelength of reported OPDs. The detectivity of the PM-HJ devices was also higher than that of the PHJ one, which is attributed to the increased efficiency of exciton dissociation in bulk heterojunction structure, increased absorption efficiency caused by formation of triclinic PbPc in the PbPc:C70 mixed film when it was deposited on a pristine PbPc layer, and high hole mobility of the PbPc-doped C70 layer.Keywords: bulk heterojunction; organic photodetector; panchromatic photoresponse; planar heterojunction; small molecule

•Inverted HTM-free planar heterojunction perovskite solar cells are constructed.•Devices are prepared by an all thermal evaporation process without thermal annealing.•A high PCE of 8.37% is obtained.•Superior stability is found for the devices for storage in ambient conditions.High efficiency and stable hole transporting material-free (HTM-free) planar heterojunction (PHJ) perovskite solar cells are constructed by directly thermal evaporating perovskite materials onto indium tin oxide substrate. A condense and homogeneous morphology is found for this perovskite film even without any annealing process. The optimized HTM-free CH3NH3PbI3−XClX/C60 PHJ device with a 35 nm ultra-thin CH3NH3PbI3−XClX layer presents a high hole extraction efficiency and a low charge carrier recombination probability, which results in a high short circuit current and fill factor. The HTM-free device shows a high power conversion efficiency of 8.37%, which is one of the highest efficiency among reported inverted HTM-free perovskite solar cells even that a thinner perovskite film is used. More importantly, the device also exhibits a superior stability in ambient conditions.

High-efficiency surface plasmon enhanced 1,1-bis-(4-bis(4-methyl-phenyl)-amino-phenyl)-cyclohexane:C70 small molecular bulk heterojunction organic solar cells with a MoO3 anode buffer layer have been demonstrated. The optimized device based on thermal evaporated Ag nanoparticles (NPs) shows a power conversion efficiency of 5.42%, which is 17% higher than the reference device. The improvement is attributed to both the enhanced conductivity and increased absorption due to the near-field enhancement of the localized surface plasmon resonance of Ag NPs.Keywords: localized surface plasmon resonance; metal nanoparticle; molybdenum trioxide; organic solar cell; small molecule;