Highly conductive and optical transparent Al-doped ZnO (AZO) thin film composed of ZnO with a Zn-Al-O interface was fabricated by thermal atomic layer deposition (ALD) method. The as-prepared AZO thin film exhibits excellent electrical and optical properties with high stability and compatibility with temperature-sensitive flexible photoelectronic devices; film resistivity is as low as 5.7 × 10 Ω·cm, the carrier concentration is high up to 2.2 × 10 cm. optical transparency is greater than 80% in a visible range, and the growth temperature is below 150 °C on the PEN substrate. Compared with the conventional AZO film containing by a ZnO-AlO interface, we propose that the underlying mechanism of the enhanced electrical conductivity for the current AZO thin film is attributed to the oxygen vacancies deficiency derived from the free competitive growth mode of Zn-O and Al-O bonds in the Zn-Al-O interface. The flexible transparent transistor based on this AZO electrode exhibits a favorable threshold voltage and I/I ratio, showing promising for use in high-resolution, fully transparent, and flexible display applications.

Giant electrocaloric effect was observed in lead-free material for the first time. A demonstration of large electrocaloric effect in 200 nm sol-gel thin film SrBi2Ta2O9 is described here. The ferroelectric hysteresis loops and the film permittivity were measured. The extracted data characterized the electrocaloric temperature change, up to 4.93K in 12V (i.e., 0.41 K V−1) near the Curie point. It is concluded that the giant electrocaloric effect exists in lead-free materials, and a large family of layered perovskite oxides may exhibit analogical property. The absence of lead allows eco-friendly application and enhances compatibility with integrated circuit process in future applications.

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High-efficiency polymer solar cells were made with a hydrophilic graphene oxide (GO) doped in poly(ethylene dioxythiophene) (PEDOT)-polystyrene sulfonic acid (PSS) composites using a structure of indium tin oxide/PEDOT:PSS:GO (40 nm)/poly(3-hexylthiophene-1,3-diyl) (P3HT)-[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) (1:0.6, 100 nm)/LiF (1 nm)/Al (70 nm). The energy conversion efficiency eta was enhanced from 2.1 to 3.8% by doping GO into the PEDOT:PSS buffer layer under AM1.5G 100 mW cm(-2) illumination in air. The pre-annealing of GO makes energy conversion efficiency 1.8 times that of the device based on a pristine PEDOT:PSS buffer layer. Because of the low price and ease of preparation, soluble graphene will be a promising buffer layer used in photovoltaic applications. Furthermore, it can be used in other electronic applications.

A versatile and generally applicable synthetic method for making second-order nonlinear optical (NLO) side-chain aromatic polyquinolines has been developed. This approach emphasizes the ease of incorporating NLO chromophores onto the pendent phenyl moieties of parent polyquinolines at the final stage via a mild Mitsunobu reaction, which provides the synthesis of NLO polyquinolines with a broad variation of polymer backbones and great flexibility in the selection of chromophores. The synthesized NLO side-chain polyquinolines possess high glass transition temperature (T g > 200 °C), good processability, and excellent thermal stability. The promising results of electrooptic (EO) activity (up to 35 pm/V at 830 nm and 22 pm/V at 1300 nm), optical loss (1.5-2.5 dB/cm), and long-term stability of the poling-induced polar order (r 33 values retained >90% of their original values at 85 °C for more than 1000 h) have demonstrated the advantages of this design approach. The excellent combination of these properties in the resulting polymers have also provided a great promise in the development of EO devices.